Docstoc

sampleof jit

Document Sample
sampleof jit Powered By Docstoc
					 JUST-IN-TIME
MANUFACTURING
                                  Just-In-Time Manufacturing


                            JUST-IN-TIME MANUFACTURING
                                TAblE oF CoNTENTS

I.    JUST-IN-TIME MANUFACTURING ......................................................................1
	     A.	   INTRODUCTION	........................................................................................1
	     B.	                        .
            JIT	PHILOSOPHY	 ......................................................................................1	
            1.	   History	of	Just-In-Time	.....................................................................2
	     	     	     From	Supermarket	to	Shop	Floor.....................................................2
	     	     2.	                       .
                  What	to	Expect	 ................................................................................3
	     C.	   VALUE-ADDED	ANALYSIS	........................................................................4
	     	     	                                                     .
                  Figure 1-1 Value-Added Analysis	 ....................................................5
	     	     	                                                     .
                  Figure 1-2 Value-Added Analysis	 ....................................................6
	     	     1.	   Don't	Forget	The	Office	....................................................................7
	     D.	   UNDERSTANDING	WASTE	.......................................................................7
	     	     1.	                          .
                  Evils	of	Inventory	 .............................................................................8
	     	     	     Figure 1-3 High and Low Levels of WIP...........................................9
	     E.	   JIT	AND	QUALITY	....................................................................................11
	     	     1.	   The	Chicken	or	the	Egg	.................................................................11
	     	     2.	              .
                  What	If	?	 ........................................................................................12
            3.	   What	is	Quality	?	............................................................................13
	     	     4.	   Preventing	Quality	Problems..........................................................13
                  Defining	the	Requirements.............................................................13
                  The	Root	Cause	of	The	Problem	...................................................14
                                                                           .
                  Figure 1-4 Getting to The Root Cause	 .........................................15
                  Keeping	Control	of	The	Process	....................................................16
                  Figure 1-5 Poka-Yoke - Speaker Box Assembly	............................17
                  Figure 1-6 Poka-Yoke - Drilling Holes in a Side Plate....................18
      F.	                                  .
            UNIFORM	PLANT	LOAD	 .........................................................................19
            1.	   Cycle	Time	.....................................................................................19
                               .
                  Workforce	 ......................................................................................20
            2.	                     .
                  Level	Loading	 ................................................................................21
                  Figure 1-7 Level Loading	..............................................................22
            3.	                                               .
                  Learning	Curve	Improvements	 ......................................................23
      G.	   SETUP	TIME	REDUCTION	......................................................................24
            1.	   Getting	Started	...............................................................................24
            2.	   Setup	Reduction	Teams	.................................................................25
            3.	   Videotaping	....................................................................................26
            4.	                             .
                  The	SMED	System	........................................................................27
                                                                           .
                  The	Four	Conceptual	Stages	of	SMED	 .........................................27
            5.	   Clamping	........................................................................................28
            6.	   Adjusting	........................................................................................28

AIDT - Just-In-Time Manufacturing - September 11, 2006                                                               i
                                Just-In-Time Manufacturing


     H.	   CELLULAR	MANUFACTURING	...............................................................29
                  Figure 1-8 Traditional Manufacturing System	...............................29
                  Figure 1-9 U-Shaped Work Cell	....................................................30
           1.	                                  .
                  U-Shaped	Work	Cells	....................................................................31
                  Figure 1-10 U-Shaped Work Cells	................................................32
                  U-Shaped	Cells	versus	Assembly	Line	Manufacturing	..................33
                  Comparison	of	Assembly	Line	and	U-Shaped	Work	Cell	 ..............33                .
                  Figure 1-11 Cellular Manufacturing System ..................................34
     I.	   PULL	SYSTEMS .......................................................................................35
           1.	                            .
                  The	Push	System	 ..........................................................................35
                  Figure 1-12 Push System..............................................................36
           2.	    From	Supermarket	to	Factory	Floor	-	The	Pull	System	.................37          .
                  Figure 1-13 Kanban Card..............................................................37
                  Figure 1-14 Production Control by Pull System ............................39
     J.	   JIT	PURCHASING ....................................................................................41
                  Figure 1-15 Typical Manufacturing Costs......................................41
           1.	    Partnerships	...................................................................................42
           2.	    Eliminating	Procurement	Wastes	...................................................43
           3.	    A	Day's	Worth	Every	Day	...............................................................44
     K.	   JIT	IN	CONJUNCTION	WITH	MANUFACTURING	RESOURCE	
     	                 .
           PLANNING	...............................................................................................45
           1.	    Which	System	?	.............................................................................45
     L.	   MANAGEMENT'S	RESPONSIBILITY.......................................................47
           1.	                .
                  Motivation	 ......................................................................................48
           2.	    Training	..........................................................................................48
           3.	    Leadership	.....................................................................................49
     M.	                            .
           IMPLEMENTING	JIT	................................................................................49
           1.	    Forming	Teams	..............................................................................50
           2.	                                         .
                  Developing	a	JIT	Startegy	 .............................................................50
     N.	   GLOSSARY	..............................................................................................52
     O.	   REFERENCES	AND	RECOMMENDED	READINGS	...............................56




ii                                        AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


I.    JUST-IN-TIME MANUFACTURING

      A.     INTRoDUCTIoN

             Why Just-In-Time manufacturing when there are dozens of other
             manufacturing philosophies from which a company may choose? Just-In-
             Time (JIT) manufacturing distances itself from the competition because no
             large capital outlays are required. Other methods promote complexity, large
             overheads, automation, and other "state-of-the-art" technologies, while JIT
             advocates simplifying and streamlining the existing manufacturing process.

             Since World War II, traditional American companies have developed a way
             of doing business that entails top management planning, re-planning, and
             more planning. Although some planning is good, it ultimately adds no value
             to the end product. Customers want quality products at competitive prices
             - they couldn't care less how much planning was required to get that product
             to them. By implementing JIT, much of the planning disappears and a large
             portion of the remaining planning is entrusted to the shop floor personnel.

             The purpose of this text is to introduce basic JIT concepts and assure you
             that JIT can work in your company. The transition to JIT often is not easy,
             but it is almost always rewarding. All employees in the company - from top
             management to direct labor - must have a clear understanding of the benefits
             that JIT offers to them and to their company. JIT is not a cure-all for every
             manufacturing problem. But, if implemented properly, JIT is a no-cost or
             low-cost method for improving your manufacturing process.

      b.     JIT PHIloSoPHY
             The basis of Just-In-Time (JIT) is the concept of ideal production. It centers on
             the elimination of waste in the whole manufacturing environment, from raw
             materials through shipping. Just-In-Time is defined as "the production of the
             minimum number of different units, in the smallest possible quantities, at the
             latest possible time, thereby eliminating the need for inventory. Remember,
             JIT does not mean to produce on time, but to produce just in time.



AIDT - Just-In-Time Manufacturing - September 11, 2006                                       1
                 Just-In-Time Manufacturing


    1.   History of Just-In-Time

         JIT is sometimes said to have been invented by Henry Ford because
         of his one-at-a-time assembly line, circa 1913. This is an incorrect
         conclusion since Ford's system could handle no variety and was
         designed for large volumes and large batch sizes of the same parts.

         JIT was invented by Taiichi Ohno of Toyota shortly after World War
         II. Ohno's system was designed to handle large or small volumes
         of a variety of parts. Many people are intimidated by JIT because
         of its association with Japan. If these people take a broader look at
         JIT, they will see that it is nothing more than good, common sense
         manufacturing.

         Ohno and his associates came to America to study our manufacturing
         processes. They determined that our system was much like the system
         that Japanese companies were using, but Japanese companies could not
         afford waste in their systems due to the devastation to their economy
         caused by World War II. While in America, Ohno learned much about
         America's culture. One of his discoveries has transformed the world's
         perspective on manufacturing.

         From Supermarket To Shop Floor

         Legend has it that Ohno got the idea for his manufacturing system
         from America's supermarket system. Ohno learned the kanban (pull)
         system from our supermarket system in which customers pulled items
         from the shelves to fill their shopping carts, thereby creating an empty
         space on the shelf. The empty space is a signal for the stocker to
         replace that item. If an item was not bought that day, there was no
         need to replace it. When item quantities become low, that is the signal
         for the stockers to order more goods from their suppliers. Customers
         are content to take just what they need, because they know that the
         goods will be there the next time they need them.

         To apply this concept to manufacturing, Ohno devised a system whereby
         the usage of parts is determined by production rates. Materials are
         pulled through the plant by usage or consumption of the parts in final

2                        AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    assembly. To obtain maximum results, Ohno decided to move the
                    machines closer together and form manufacturing cells.

                    The JIT system continued to evolve, with the central thrust being the
                    elimination of waste. Ohno's system has become a totally flexible
                    system in which production rates are determined by the end user rather
                    than the producer.

             2.     What To Expect

                    While the prevailing view of JIT is that of an inventory control system,
                    it is much more. JIT is an operational philosophy which incorporates
                    an improved inventory control system in conjunction with other
                    systems, such as:

                    •      A set-up time improvement system.
                    •      A maintenance improvement system.
                    •      A quality improvement system.
                    •      A productivity improvement system.

                    A properly implemented JIT system should:

                    •      Produce products customers want.
                    •      Produce products only at the rate that customers want them.
                    •      Produce with perfect quality.
                    •      Produce instantly with zero unnecessary lead time.
                    •      Produce with no waste of labor, material, or equipment. Every
                           move has a purpose and there is no idle inventory.

                    An overview of JIT literature suggests that the steps or elements of
                    the implementation process generally (though not always) include the
                    following:

                    •      Reductions in set-up time.
                    •      Utilization of a formal preventive maintenance program.
                    •      Utilization of quality circles.
                    •      Utilization of cellular manufacturing techniques.
                    •      Cross-training of employees.

AIDT - Just-In-Time Manufacturing - September 11, 2006                                     
                        Just-In-Time Manufacturing


                •      Quality certification of suppliers.
                •      Reductions in vendor lead time.
                •      Reductions in lot sizes.
                •      Sole sourcing.
                •      Presence of one who "championed the cause of JIT within the
                       firm.

                Benefits touted as results of JIT implementation include:

                •      Reductions in down time.
                •      Reductions in inventory.
                •      Reductions in scrap and re-work.
                •      Reductions in workspace.
                •      Increased inventory turns.
                •      Increased labor utilization.
                •      Increased equipment utilization.
                •      Improved service to customers.

    C.   VAlUE-ADDED ANAlYSIS

         Maybe you believe that your company is efficient enough and that the benefits
         of JIT are not worth the frustration and stress associated with change. At this
         point you have a decision to make—you can adopt a new company motto such
         as “We’re no worse than anybody else,” or you can take positive steps toward
         improving the process. To strengthen the incentive for change, companies
         should identify the inefficiencies (wastes) in their present manufacturing
         processes.

         To identify waste in your company, a value-added analysis should be
         performed. We must always be aware that any activity that does not add value
         to a product is waste. There are specific methods for performing a value-added
         analysis but we will use a simplified approach for our purposes. Take a pad
         and pencil and go out on the shop floor. Pick a product and follow it through
         the entire manufacturing process from raw materials to shipping. Note every
         activity performed on the product. Do not get a routing slip to see how the
         process is supposed to go, but accurately record the process including delays,
         transportation, inspection, storage, etc. Figure 1-1 on the following page is a
         value-added analysis for a machined part.

                               AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                                     FIGURE 1-1
                                Value-added Analysis
                                                         VAlUE    NoN-VAlUE
                   ACTIVITY                              ADDING    ADDING
    			1	   Receive	aluminum	from	vendor
    		2	    To	storage	rack	via	forktruck
    		3	    Store	aluminum
    		4	    To	shear	via	forktruck
    		5	    Wait	for	shear
    		6	    Set	up	shear
    		7	    Shear	aluminum
    		8	    Stack	part	on	pallet
    		9	    Wait	till	have	correct	batch	size
    10	     Wait	for	forktruck
    11	     To	storage	via	forktruck
    12	     Store	part
    13	     To	CNC	mill	via	forktruck
    14	     Set	up	CNC	mill
    15	     Clamp	part	in	vise
    16	     Mill	inside	recess
    17	     Change	tool
    18	     Drill	pilot	holes
    19	     Change	tool
    20	     Drill	finished	holes
    21	     Change	tool
    22	     Tap	holes
    23	     Remove	part	from	vise
    24	     De-burr	part
    25	     Stack	part	on	pallet
    26	     Wait	till	have	correct	batch	size
    27	     Wait	for	forktruck
    28	     To	storage	via	forktruck
    29	     Store	part
    30	     Sell	part
    31	     To	shipping	dock	via	forktruck
    32	     Ship	part

                                                TOTALS     8        24

AIDT - Just-In-Time Manufacturing - September 11, 2006                        
                            Just-In-Time Manufacturing


            Figure 1-1 showed us that 32 total activities take place before the customer
            receives the part. Only eight of these activities add value, therefore all other
            activities must be considered waste. Even though some of these wasteful
            activities are absolutely necessary, they are still waste and should be viewed
            as such.

            We will now streamline the manufacturing process, using JIT techniques
            that will be discussed in-depth later. Figure 1-2 shows that non-value-added
            activities have been reduced to nine instances.

                                    FIGURE 1-2
                               Value-added Analysis

                                                               VAlUE        NoN-VAlUE
                   ACTIVITY                                    ADDING        ADDING
    			1	   Receive	aluminum	from	vendor
    		2	    To	shear	via	forktruck
    		3	    Set	up	shear
    		4	    Shear	aluminum
    		5	    Set	up	CNC	mill
    		6	    Clamp	part	in	vise
    		7	    Mill	inside	recess
    		8	    Change	tool
    		9	    Drill	pilot	holes
    10	     Change	tool
    11	     Drill	finish	holes
    12	     Change	tool
    13	     Tap	holes
    14	     Remove	part	from	vise
    15	     De-burr	part
    16	     Sell	part
    17	     Ship	part
                                              TOTALS                8          9




6                                  AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             Perhaps nonvalue-added activities can be reduced further and perhaps they
             cannot. The concept is to keep an open mind as to how you can continuously
             improve the process. All remaining steps are now optimized to produce the
             part as efficiently as possible.

             1.	    Don't	Forget	The	Office

                    Evaluating a process using a value-added analysis should not be limited
                    to the shop floor. All processes in an organization can benefit from
                    eliminating waste. Everything from purchase orders to typing memos
                    should be streamlined. How long does a purchase order sit on someone’s
                    desk awaiting a signature, only to be changed, retyped, and submitted
                    again? It may then stall at a higher level in the organization and so
                    on up the ladder. Not only will the techniques of JIT manufacturing
                    help eliminate some of the nonvalue-added steps in your process, but
                    in doing so they will reduce lead time, improve throughput time and
                    increase quality.

      D.     UNDERSTANDING WASTE
             Ask almost any shop floor employee the definition of inventory and the likely
             answer will be “you know all this stuff stacked up around here and all that stuff
             in the warehouse”. Many employees (and some supervisors and managers) do
             not understand that Work-In-Process (WIP) is also inventory. Pure and simple
             inventory is waste. Another way to describe inventory is money loaned out
             of a company’s pocket that has yet to be repaid.

             JIT is much more than a plan for decreasing inventory, it is a manufacturing
             philosophy for eliminating waste. For our purposes, waste can be defined
             as something other than the essential resources of people, machines, and
             material needed to add value to the product. Anything else, such as inventory,
             scheduling, meetings, warehousing goods, management, and moving stock
             can be considered wasteful because these actions do not directly add value to
             the product. All waste cannot be purged from the system, however, we must
             strive toward that ideal goal. Above all it must be ever present in the attitudes
             of our manufacturing system that cost without value is waste.



AIDT - Just-In-Time Manufacturing - September 11, 2006                                       
                    Just-In-Time Manufacturing


    A typical company produces excess inventory with the idea that “we can use
    this stuff when the next order comes in." Routinely these parts are forgotten
    when the next order is placed. Other than initial costs of the products, they are
    also paying for moving the product, warehouse space, fork trucks, warehouse
    personnel, tracking the products, and moving the products again, etc. One
    company that we visited was constantly plagued with the problem of misplaced
    inventory. They had numerous storage bins, plus inventory was sometimes
    “temporarily” placed on the shop floor in different places. More often than
    not, new parts would be made when the internal customer needed the parts,
    because nobody knew the parts already existed. Another company we visited
    wastes money on rust preventatives and the time-consuming task of removing
    rust from parts in storage solely for the benefit of excess inventory.

    1.     Evils of Inventory

           Although inventory has long been accepted as a necessary evil we must
           remember that it is still an evil. Why is inventory evil? Traditional
           manufacturing processes build in safety stock at every station throughout
           the entire system, from extra raw materials to warehouses full of
           completed products. This superfluous WIP provides manufacturers with
           a means to endure the problems, rather than solving the problems at the
           root cause. Figure 1-3 shows how some problems can be disguised by
           excess inventory. The water shown in the graphic is inventory and the
           rocks depict manufacturing problems. As the water level drops, more
           and more rocks begin to surface.




                          AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                                     FIGURE 1-3
                            High and low levels of WIP




AIDT - Just-In-Time Manufacturing - September 11, 2006   
             Just-In-Time Manufacturing


     Let’s take a hypothetical look at a company that is reducing inventory.
     ACME manufacturing produces roller skates for a major toy company.
     In one process, bearings are pressed into the skate wheels. Frequently
     a wheel does not run true because the bearings are inserted at an angle.
     This problem can only be detected after the wheel has been assembled.
     When such a problem does occur the entire wheel assembly must
     be discarded. This problem was undetected for years because the
     manufacturing line never slowed down due to these defects. Extra
     wheels and bearings were always available to the assembler.

     After inventory was reduced, the wheel assembler had difficulty
     meeting demand. He no longer had the inventory cushion to hide the
     quality problems. There was not enough “extra” WIP to allow him to
     continually produce bad parts. Now that the quality problem is evident,
     a concentrated effort must be made to solve it.

     Do not make the mistake of raising WIP to allow the line to flow
     smoothly. We need the problems to surface so that we can solve them.
     Remember, the WIP is not the solution to the problems it is only a
     means to wade through them. Inventory must first be reduced, then
     you can solve the problems.

     Inventory must be decreased using a systematic approach. A methodical
     approach is to cut inventory by one half then solve the problems then
     cut half of that inventory and solve the problems. Continue this process.
     See Xeno’s paradox mentioned in Section E.




10                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


      E.     JIT AND QUAlITY
             The single most substantial ingredient of JIT is quality. It is impossible for JIT
             to be successful until the company has drastically improved its attitude toward
             quality. In the language of the Malcolm Baldrige National Quality Award,
             quality is a “race with no finish line." The ultimate aspiration is to satisfy
             all customers (internal and external) all the time. The Wallace Company, a
             past winner of the Baldrige Award, installed a buzzer on the shop floor that
             sounded anytime a customer called their customer service hot line. Instantly
             all workers knew they had a dissatisfied customer. Can you imagine installing
             such a device in a traditional manufacturing company?

             1.     The Chicken or The Egg

                    Analogous to the familiar chicken or the egg question, it is often asked,
                    “Which comes first, quality or JIT?” Quality is a two way street; JIT
                    is impossible without quality, but quality is directly enhanced by JIT.
                    Although quality is possible without JIT, it requires the use of wasteful
                    procedures such as inspection and rework. JIT proposes the idea of
                    “do it right the first time” rather than inspecting in quality. In a JIT
                    environment, each internal customer (the next operator down the line)
                    must be completely satisfied by the previous operation. Any problems
                    in quality are resolved immediately, rather than allowing them to
                    contaminate the system further.

                    To produce quality you must install quality. Quality must evolve from
                    both sides at the same time. To allow operators to satisfy their internal
                    customers, quality procedures, materials, machines, and mindset must
                    be present. JIT is not possible without quality, but JIT is a means by
                    which quality is achieved.

                    A mathematics riddle known as the Xeno’s paradox asks if a person
                    walks toward a wall, each step being one half as large as the previous
                    one, when will that person reach the wall? The answer is "never", but
                    that person is continuously getting closer and closer to his or her goal.
                    Continuous improvement in quality must be viewed in the same way.
                    If you set a standard at 95 percent, people figure that they are doing
                    fine as long as they are at or near that objective. Companies have to

AIDT - Just-In-Time Manufacturing - September 11, 2006                                       11
                   Just-In-Time Manufacturing


          be motivated to advance quality to increasingly higher and higher
          standards. Ultimately the goal should be perfection.

     2.   What If?

          The alternative to setting standards at the highest possible level becomes
          clearer when you look at the consequences of “almost, but not quite.”
          If 99.9 percent is good enough, then...

          •      Two million documents will be lost by the IRS this year.

          •      22,000 checks will be deducted from the wrong bank accounts
                 in the next 60 minutes.

          •      1,314 phone calls will be misplaced by telecommunication
                 services every minute.

          •      12 babies will be given to the wrong parents each day.

          •      291 pacemaker operations will be performed incorrectly this
                 year.

          •      315 entries in Webster’s Third New International Dictionary
                 of the English Language (unabridged) will turn out to be
                 misspelled.

          Incidentally, 99.9 percent accuracy would be a remarkable improvement
          in the context of current performance levels in most of today’s traditional
          manufacturing companies. Employees should be producing by the
          following code:

          •      Defect-free output is more important that output itself.

          •      Defects, errors, and breakdowns can be prevented.

          •      Prevention is cheaper than rework.



12                        AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             3.     What is Quality?

                    One of the great gurus of quality, Phil Crosby, says that companies
                    often have a misconception of quality. He says that the true definition
                    of quality is meeting requirements—not an intuition for aesthetics,
                    roundness, or perfection—but something that can be truly measured.
                    If a Yugo (economy car of the the early 1970s) meets its customer's
                    requirements as well as a Rolls Royce meets its customer's requirements,
                    then it can be argued that the Yugo is as much a quality car as a Rolls
                    Royce.

                    Now that we understand what quality is and what it can do for us, how do
                    we get quality? The key is to obtain quality at the source. The sources
                    for quality are the manufacturer’s and vendor’s processes, machines,
                    and operators. Contrary to traditional beliefs, the source of quality is
                    not the inspection bench.

             4.     Preventing Quality Problems

                    To dismantle the inspection bench mentality, we must take positive
                    steps in prevention of quality problems. Specific guidelines and
                    rigorous procedures must be established. The steps toward attaining
                    a quality product are to first define the requirements, get the process
                    under control, and then keep the process under control.

                    Defining	the	Requirements

                    Many manufacturing companies do an inadequate job of defining
                    quality requirements. If you are looking at a part or a process, and
                    say “that’s good enough” then you have not sufficiently defined your
                    requirements. The real definition of quality is meeting both internal
                    and external customer requirements. Employees and vendors should
                    have strict guidelines that distinguish good parts (quality) from rework
                    or rejected parts so 100 percent customer satisfaction can be reached.

                    Let us look back at our ACME manufacturing example. The assembler
                    had no specific requirements for pressing the bearings into the wheel.
                    He was told that the wheel must run true. What is true? How much

AIDT - Just-In-Time Manufacturing - September 11, 2006                                    1
             Just-In-Time Manufacturing


     leeway does he have? Can the bearings be somewhat angled or must
     they be exactly straight? The assembler should be supplied with strict
     criteria for quality such as “each bearing should be pressed into the
     wheel at a perpendicular angle plus or minus one degree”. He now
     knows what is expected and what is considered good enough.

     The Root Cause of the Problem

     To get the process under control, you must first find the root cause of
     the problem. This can be accomplished by running the gamut from
     simple methods such as pareto and matrix analysis to complicated
     design experiments. A common problem is to attack the symptom
     and not the problem. For example, if a breaker tripped at your house,
     you could reset the breaker and hope for the best, replace the breaker
     box, or you could check for an overloaded plug (too many appliances
     plugged into one outlet). In your manufacturing process, don’t make
     the mistake of rewiring the whole house before the actual problem is
     diagnosed.

     Everyone has worked on a problem that magically went away, although
     you were not exactly sure why. It could be any one of the solutions
     you tried or a combination of any two. In this case, you do not know
     if you have gotten to the root cause or not. You must be able to turn the
     problem on and off to ultimately conclude that the problem has been
     solved. If you can not turn the problem on and off it is likely that you
     have solved a symptom rather than a problem. At this point you should
     ask “why” and continue to ask “why” until you find the root cause.
     Figure 1-4, shown on the following page, illustrates the problem of
     bad service at a restaurant.




1                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing



                                     FIGURE 1-4
                            Getting To The Root Cause




AIDT - Just-In-Time Manufacturing - September 11, 2006   1
              Just-In-Time Manufacturing


     Obviously you cannot turn the problem of the owner’s offspring on and
     off, but asking “why” did get you to the root cause. Disciplining the
     waitress will not solve the real problem. The root cause of this problem
     is a bad promotion policy. The long-term solution is a change in that
     policy. If you ask “why” enough times you will get to the root cause.

     Keeping Control of the Process

     Once you have found the solution, keeping the process under control
     is an easier task. Statistical Process Control (SPC) is a method of
     managing a process by gathering information about it and using that
     information to adjust the process to prevent problems from occurring.
     Using SPC is one way to keep your process under control. Poka-yoke,
     a Japanese word for fail-safing, should also be applied. In the Poka-
     yoke theory, parts and processes are designed so that doing the job
     right is easier than doing it wrong. An example of this is to design a
     part that is asymmetrical so that it fits only one way, thus eliminating
     misinstallation. Machines can be fitted with limit switches that will not
     allow it to cycle if all processes are not completed in the correct order.
     These methods should not only be used by your company but by your
     vendors as well. The following are such examples (Hirano, 131):




16                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                                      FIGURE 1-5
                        Poka-Yoke - Speaker box Assembly

    Description of Process: Front	plates	were	attached	to	speaker	boxes.

Before Improvement:                            After Improvement:

It was difficult to determine the correct      The positions of the mounting holes were
orientation of the speaker boxes because       made asymmetrical on the top so that
the mounting holes were symmetrical at         incorrect mounting is impossible. Upside
the top and bottom. Correct mounting           down mounting is completely eliminated.
depended exclusively on the worker's
vigilance, with the result that the speaker
boxes were sometimes mounted to the
front plates upside down.




AIDT - Just-In-Time Manufacturing - September 11, 2006                               1
                              Just-In-Time Manufacturing


                                         FIGURE 1-6
                       Poka-Yoke - Drilling Holes in a Side Plate

Description of the Process: A workpiece, a side plate, is set into position on a drill press
and dowel holes are drilled. The workpiece is essentially symmetrical, and back and front
are difficult to distinguish at a glance, although two edges are grooved along their length.
Before Improvement:                             After Improvement:

The workers, when setting the workpiece         The grooved edges of two sides of the
into position, checked to see whether the top   workpieces are used as guides for setting
and bottom of the plate were in the correct     up the plates correctly. A limit switch is
position. They then drilled the dowel holes.    mounted on the jig and interlocked with
Inexperienced workers sometimes confused        the start switch so it is impossible to start
top for bottom and drilled the holes in         the drill press if the side plate is set in the
the wrong places. Even veteran workers          wrong position. Defects due to defective
sometimes mounted the part backwards.           holes are completely eliminated.
These defects were discovered only at
assembly.




1                                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


      F.     UNIFoRM PlANT loAD
             The diversion between traditional manufacturing philosophy and JIT becomes
             apparent when discussing the concept of Uniform Plant Load. Everyone will
             agree that we need to eliminate waste and strive for quality to receive the
             most benefit from our manufacturing systems, but there are two views on how
             to go about this. The traditional system calls for production at the “machine
             rate” while JIT advocates production at the “customer requirement rate.” The
             JIT concept of Uniform Plant Load states that balance between operations is
             more important than speed, and ideally we should never produce faster than
             the customer requirement rate.

             The concept of Uniform Plant Load incorporates two radically different
             facets of production. They are rate of production (cycle time) and frequency
             of production (level loading). It must be remembered that neither of these
             concepts will achieve maximum results until the process is under control and
             quality has been improved to world-class or near world-class standards.

             1.     Cycle Time

                    Traditional definitions of cycle time include the time it takes a machine
                    to cycle through its process or the time from start to completion of
                    a product (throughput time). Under JIT, cycle time is the total time
                    required for a worker to complete one cycle of operations, including
                    walking, load/unload, inspect, etc. Cycle time should equal the customer
                    requirement rate, or better stated the sales rate. We should view the last
                    step in the manufacturing process as when the product gets sold, not
                    when the product is completed. This rate is also expressed in terms of
                    takt time. Takt time is the total daily operating time divided by the
                    total daily requirement. Takt time tells you how many hours, minutes,
                    or seconds are required for each part.

                    Takt is a German word for baton. In comparing a manufacturing process
                    to an orchestra, the rate at which the orchestra leader moves the baton
                    is the rate at which the orchestra plays, just as the rate of customer
                    requirement is the rate of company production.



AIDT - Just-In-Time Manufacturing - September 11, 2006                                      1
              Just-In-Time Manufacturing


     Companies that have produced as fast as possible (machine rate) for
     many years often struggle with the concept of slowing down individual
     machines so as to achieve perfect balance between operations. If your
     customer requirement rate is 20 parts per month, then why would you
     want to produce 30 parts per month? This would lead to the evils of
     inventory—the consumption of space, waste in motion, and materials
     that hide problems. Conceptually, each machine should run as if a
     rheostat were attached. The rheostat could be dialed up or down as
     needed to produce at the exact rate required. If the requirement rate
     changed from month to month then the production rate could be altered
     to meet these requirements. If you set the last operation to the sales rate
     then each preceding operation should feed the last operation at that rate.
     This system can then be exploded backwards throughout the plant until
     the first operation (usually raw materials) is reached.

     Workforce

     If ten people are producing 20 parts per month in August, but only
     ten parts are needed in September, five people should then be capable
     of producing the needed ten parts so that labor costs remain constant.
     This reduction can only be accomplished with a good physical plant
     layout (to be discussed later) and a well-trained, flexible workforce.
     The logical questions at this point are: “Where do the five people go?”,
     and “Where do they come from when production goes back to 20?”
     It must be made abundantly clear that the purpose of implementing
     JIT is not to reduce the workforce. You can now use this idle time
     to cross-train employees for even more flexibility. When not on
     the production line employees can perform other tasks, attend team
     meetings, do preventative maintenance, make plans to further improve
     the process and so forth. Rather than producing extra parts and dealing
     with inventory, you are now optimizing employee time. That leads us
     to the golden rule of JIT: Machines can be idle but people cannot.

     We should not make the mistake of trying to find the perfect balance
     between parts produced and manpower required. There is no perfect
     balance. We must decide how many parts the line should produce that
     month, week, or day and balance to that number. Remember, the answer
     is not to run the line as fast as possible, but to produce to the customer

20                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    requirement rate by deciding how fast the line must run to meet the
                    particular deadline and how many people are needed for this rate.

             2.     level loading

                    The second facet of Uniform Plant Load is level loading. Level loading
                    suggests that if you sell a product every month, then make the product
                    every month. Ideally, if you sell a product every day, then make the
                    product every day. You must make your products as frequently as your
                    customers require them.

                    Let us assume that your company produces three products–alphas,
                    betas, and deltas–from the same line. Cycle time has been implemented,
                    therefore, your equipment is running at the right speed. For example,
                    we will say that in the month of March we will need 25 percent alphas,
                    50 percent betas, and 25 percent deltas. In a traditional manufacturing
                    environment alphas would be produced for 25 percent of the month.
                    We would then change over (setup) and run betas for 50 percent of the
                    month; change over again and run deltas for the remaining 25 percent
                    of the month. Do your customers buy alphas the first week, betas the
                    next two weeks, and deltas the last week?

                    The next logical step may be to produce a week’s worth every week.
                    You have instantly gone from setting up 3 times a month to 12 times a
                    month. Traditional manufacturing will be quick to note that valuable
                    time will be spent setting up with no time to produce. Increased number
                    of changeovers can be accomplished only after setup time has been
                    reduced to allow this. We will address the subject of setup time in the
                    next chapter. In a nutshell, if we are to change over four times more
                    often, then we must reduce setup time to 25 percent of its original time.
                    To meet these goals you must take a structured step-by-step approach.
                    A lofty goal may be to produce a day’s worth every day. It is true this
                    is a very high standard but Toyota is currently producing two hours
                    worth every two hours.




AIDT - Just-In-Time Manufacturing - September 11, 2006                                     21
             Just-In-Time Manufacturing


                     FIGURE 1-7
                    level loading




     Setup	reduction	has	a	direct	correlation	to	batch	size.		If	setups	are	
     reduced	by	50	percent	then	batch	sizes	can	be	reduced	by	50	percent.	   	
     Additional	direct	benefits	of	level	loading	are	learning	curve	improve-
     ments,	increased	mix	flexibility,	reduced	inventory,	shorter	lead	times,	
     and	quality	improvements.


22                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    Let us look at our original process of producing alphas for one week,
                    betas for two weeks and deltas for the remaining week. If a customer
                    calls in a change order for more alphas the third week of the month; a
                    three-week delay occurs before alphas are being produced again. If you
                    are on a daily or even weekly production schedule, reaction to changes
                    in mix can be almost immediate. Production of alphas can begin the
                    next day or you could change over the same day if requirement rate of
                    betas and deltas would allow.

                    As the system begins to produce at the customer requirement rate and
                    reduced setup times are translated into smaller batch sizes, lead times
                    are also reduced. When a product is being manufactured monthly, lead
                    times are expressed in months. Weekly manufactured parts require
                    lead time in terms of weeks and daily parts in terms of days. There is
                    now no need for extravagant scheduling and tracking systems. If the
                    requirement rate changes, parts can be put into the queue at the next
                    changeover period.

                    As stated earlier there is a direct correlation between setup reduction
                    and batch sizes. The same can be said for batch sizes and potential cost
                    of failure. If a batch size is cut in half, the potential cost of rework or
                    scrap is cut in half. A streamlined manufacturing process dictates that
                    quality problems will be less likely and if they occur will be much easier
                    to detect and correct. Smoother production runs need fewer adjustments,
                    therefore quality becomes more predictable.

             3.     learning Curve Improvements

                    Learning curve improvements are achieved when virtually every day
                    is the same. If you are producing all of your products at the customer
                    requirement rate each day then the days become more complex but each
                    day is the same as the day before. Setups occur every day, therefore
                    there is not time to forget the setup procedure as was the case with
                    infrequent setups. There is no time to fall into a pattern for weeks only
                    to have abrupt changes that require relearning the setup and production
                    process for the next product. Once the employee gets into the rhythm of
                    daily production, the day-to-day learning curve virtually disappears.


AIDT - Just-In-Time Manufacturing - September 11, 2006                                       2
                          Just-In-Time Manufacturing



                 Uniform Plant Load allows us to produce at the exact rate and frequency
                 that the customer requires. Other aspects of JIT—setup reduction,
                 machine cells, pull systems, JIT purchasing, and scheduling—are
                 methods used in achieving plant balance.

     G.   SETUP TIME REDUCTIoN
          Setup time is the interval between the production of one good part and
          the production of another good but dissimilar part. Setup reduction is a
          prerequisite to implementing many aspects of JIT by directly or indirectly
          influencing cycle time, level loading, work cells, pull systems, cost, WIP,
          purchasing, floor space, quality, operator numbers, and batch sizes. Everyone
          will agree that a two-hour setup reduced to two minutes is a great productivity
          improvement, but this saved time should not be applied to longer production
          runs that increase batch sizes. An hour saved that is transferred to the production
          of parts simply puts those parts in inventory, which is the exact opposite of
          what we are striving for. Our objective is to apply this hour to more frequent
          setups, thus giving us more flexibility to better implement JIT.

          1.     Getting Started

                 Our mission is to reduce setup time by 75 percent on a low-cost or
                 no-cost basis. Some machines will require a little more setup time and
                 some a little less, but 75 percent reduction is our initial goal. This may
                 not be accomplished in a week or a month, but can be achieved through
                 continuous improvement.

                 You must first decide which setup to work on. A good rule of thumb
                 is to select your most complex setup. Typically this is the setup that
                 causes the largest bottleneck (takes the most time), and therefore offers
                 the opportunity for the largest time savings. After a particular setup
                 has been chosen, a Setup Reduction Team must be formed. The next
                 problem that arises is who should be on the Setup Reduction Team.




2                                AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             2.     Setup Reduction Teams

                    Traditional management behavior seems to indicate a belief that the
                    managers and the engineering staff have all the solutions. In recent
                    years new management approaches, specifically TQM (Total Quality
                    Management), have disproved the myth that management best knows
                    how to solve all manufacturing problems. The new Setup Reduction
                    Team should consist of the real experts—the operators and setup
                    people. Contrary to traditional management’s beliefs, these people
                    have superior knowledge of their machines and the process. The typical
                    Setup Reduction Team should have three to five shop floor personnel—a
                    combination of operators and setup people, one to two engineers and
                    possibly a manager.

                    You will notice that the single largest component on the Setup Reduction
                    Team is the shop floor personnel. They probably have all the answers to
                    reduce setup time but until now had no avenue to impart their wisdom.
                    The reason more engineers are not involved with the group is that
                    most setup problems are not engineering problems. Engineers tend to
                    emphasize the mechanics of the setup, but the real reasons time is lost
                    are lack of preparation, lack of organization, and operator error. Such
                    problems may include not knowing what the next job is, setting up for
                    the wrong job, inability to find a forktruck driver or the forktruck is
                    in use, inability to find or not having the right tools, broken tools, not
                    remembering the exact setup procedure, not having the right bolts, or
                    having no nuts for those bolts. The mechanics of the setup may or may
                    not need to be modified or, if so, only after other improvements have
                    been enacted.

                    After the team has been selected, proper training in team concepts must
                    take place. The team should know its mission and act on its findings,
                    not just study and make recommendations. Team training is a separate
                    subject in itself and space does not allow us to pursue the topic here.
                    There are many good texts and seminars offered in this area that will
                    allow you to learn team training concepts.	




AIDT - Just-In-Time Manufacturing - September 11, 2006                                      2
                  Just-In-Time Manufacturing


     3.   Videotaping

          If a picture is worth a thousand words, a videotape is worth at least a
          million. The single best way to document and analyze a setup is with
          videotape. A verbal description or written account of a setup will not
          give you the detail of a video. Many nonvalue-added steps can be
          uncovered that would otherwise remain camouflaged by other means
          of documentation.

          Obtaining a credible videotape is often not easy. One major dilemma
          that occurs is a phenomenon known as the Heisenberg principle. Simply
          stated this idea is the belief that something that is being observed is
          changed merely by the fact that it is being observed (Hay, 63). If
          workers know that they are being taped they will perform the setup with
          a much greater sense of urgency. Outside preparations may occur that
          are not normally done. These actions lead to a misrepresentation of
          the true time and steps involved in a setup, thus defeating the purpose
          for videotaping.

          Another problem that may occur is apprehension about being videotaped.
          Operators may fear that management will use the tape to place blame
          for productivity problems, or to teach others how to do their job, or
          that other team members will ridicule their performance. The number
          of rumors that can surface when a video camera appears is infinite.
          The best deterrent to these problems is prevention. Operators should
          be briefed on the reasons for documentation prior to any videotaping
          with all questions being answered then. It should be abundantly clear
          that no additional actions should be taken in the documented setup
          and that safety will never be neglected to gain speed. At no time will
          any guards be removed, parts fastened less securely, work be done on
          moving equipment, etc.

          One method to obtain more “true” documentation is to do videotaping
          without announcement. Place the video camera in position just prior
          to the setup, thus allowing no time for special preparations. The
          documentation should include the last part from the previous job
          coming off the machine. The timer should then be set and everything
          should be taped from that point on. Tape continuously even if no work	

26                       AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    is being done on the machine. When the first good part from the new
                    job is finished, the documentation is complete.

                    Once the videotape is complete, the Setup Reduction Team begins
                    a detailed analysis of the setup procedure. The primary focus of the
                    analysis is to reduce machine downtime. Team members generate a list
                    of problems to solve and possible solutions for the problems.


             4.     The SMED System

                    One proven technique for optimizing setup time is the Single-Minute
                    Exchange of Die (SMED) system. The SMED system was founded
                    by Shigeo Shingo while consulting with Toyota in 1969. No man has
                    revolutionized setup reduction philosophy as much as Shingo. He has
                    won numerous productivity improvement awards in Japan, the United
                    States, and the world over. The basis of SMED is the performance
                    of setup operations in under ten minutes, i.e., in a number of minutes
                    expressed in a single digit.

                    The Four Conceptual Stages of SMED:

                    •      Internal setup and external setup are not distinguished.
                    •      Internal setup and external setup are distinguished.
                    •      Internal setup is converted to external setup.
                    •      Streamline all aspects of the setup.

                    The concept behind the SMED system is distinguishing internal setup
                    (performed while the machine is off) from external setup (performed
                    while the machine is producing) and converting internal to external
                    setup. This is accomplished by examining the true functions of setups.
                    Once this step has been successfully applied, only internal activities are
                    left. An example of this would be to locate and organize all the bolts
                    needed for the next setup while the previous job is running instead of
                    rushing around looking for bolts after the machine is off.

                    After the activities of the setup have been corrected, the mechanics of
                    the setup need to be addressed. Or as Shingo states, “all aspects must
                    be streamlined". Two major categories in this area are clamping and
AIDT - Just-In-Time Manufacturing - September 11, 2006                                      2
                  Just-In-Time Manufacturing


          adjusting. Numerous texts have been written concerning quick die
          change, Poka-yoke (fail-safing), fixtures, setup reduction, and similar
          topics. Although we will deal with setup mechanics in general terms,
          further study in this area is recommended.

     5.   Clamping

          Video documentation will often reveal that substantial time is spent
          loosening and tightening nuts and bolts. Threads are a very inefficient
          method for speed in a setup, because only the last half turn of a bolt
          or nut gets the job done. The first fifteen, twenty or twenty-five turns
          are a useless waste. Another problem with threads is the use of tools.
          Picking up a wrench —if you can find it—is also a waste; therefore
          we must look for alternative methods for clamping. Do not make the
          mistake of trying to buy the solution. While it is true that hydraulic
          or pneumatic clamps save much time and wasted motion, they violate
          our no-cost or low-cost policy. Look for methods that require only
          one or two motions such as cams, levers, or pins. You can explore
          purchasing “high-tech” clamping systems after all other avenues have
          been exhausted or continuous improvement has stagnated.

     6.   Adjusting

          The videotape may also show large amounts of time is being spent to
          get the job to run right. Traditional thoughts have been that adjustments
          are necessary, therefore no energy has been expended to eradicate the
          problem. Our aim is to have quality parts produced the first time, every
          time. Bad parts should never be produced due to setup. The problem
          with adjustments arises because most machines are infinitely adjustable.
          For example, something on a machine is measured, or tightened down,
          then a part is run. Then the machine is adjusted, tightened down, then
          another part is run. This continues until a good part is produced. After
          analyzing the videotape you may conclude that the machine needs to
          be adjusted to a few set positions. At this point the machine should
          be converted to positive stops for those positions rather than endlessly
          measured positions or better yet the machine can be designed to be
          self-positioning.


2                        AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    Reducing setup is a crucial step toward accomplishing JIT manufacturing
                    goals. Setup reduction is considered a high priority because it affects
                    so many facets of JIT. Setup reduction is much easier than most people
                    think after traditional methods have been purged. It is extremely
                    important to adopt new perspectives that are not bound by old habits.

      H.     CEllUlAR MANUFACTURING
             The traditional method of arranging a manufacturing facility is by departmental
             speciality—that is, each department houses specialized equipment or
             technology. All the lathes, milling, drilling, grinding and assembly would be
             done in completely separate departments. Production in large batch sizes is
             inevitable when factories are laid out in this manner. Figure 1-8 illustrates a
             traditional manufacturing system. (Black, 34)

                                     FIGURE 1-8
                        Traditional Manufacturing System




AIDT - Just-In-Time Manufacturing - September 11, 2006                                    2
                    Just-In-Time Manufacturing


     The JIT philosophy maintains that a manufacturing floor be laid out by product
     rather than by function. All equipment should be dedicated to a product or
     family of products and organized logically in the order in which the various
     processes are performed on that family of products. Two characteristics must
     be fulfilled before a group of machines can be deemed the optimal JIT work
     cell. The first is whether the product is flowing one at a time from machine
     to machine, and, secondly, whether the cell has the flexibility to produce at
     different rates with varying crew sizes (cycle time). See Figure 1-9.

                           FIGURE 1-9
                       U-shaped Work Cell




     Many JIT purists argue that one-at-a-time flow is a necessity in a JIT work
     cell. It is true that batches of one are the optimum size for waste reduction,
     but we are attempting to implement practical JIT. The end goal is to have
     operation two start as soon as the part clears operation one (batch size of
     one). But practical JIT champions the idea of continuous improvement. JIT	

0                         AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             advocates batch size reduction as dictated by the setup time. Your process may
             not allow for batch sizes of one. If some parts are forced to the next operation
             then so be it. Continue to practice the doctrine of JIT and the batch sizes will
             continue to decrease.

             To dedicate the machines and physically place them together but continue
             to produce in large batch sizes at the machine rate (maximum output) would
             make no sense. JIT work cells must be adjustable to be able to produce at
             the customer requirement rate. After the customer requirement rate has been
             determined, you must ascertain the number of operators needed in the work
             cell to produce the exact amount of products required.

             One common concern about placing machines in cells is whether they lose
             their flexibility by being dedicated to that cell. Can machines work on parts
             not dedicated to that particular cell? The answer is yes. Some companies have
             found that they can produce parts through the work cell part of the time while
             at other times the machines can be scheduled independently as if they were
             not in a work cell. Machines can also be placed on casters to form temporary
             work cells to get the ultimate in flexibility. Work cells can be formed, taken
             apart, or modified to satisfy customer requirements. If machines are too heavy
             to be mobile a pull system can be used so each machine can function as if it
             were in two or three cells.

             As discussed in the Uniform Plant Load section of this text, the only way to
             keep labor costs constant is to flex the crew size. Operators must be cross-
             trained to perform many tasks properly in a work cell thus allowing one
             operator to run many machines.	

             1.     U-shaped Work Cells

                    The most flexible work cell is the U-shaped layout. The U-shaped work
                    cell should be large enough to allow operators to work side by side,
                    back to back, but not so close as to inconvenience each other. Shown
                    on the following page is an example of a U-shaped work cell staffed
                    with six operators and another with three operators.




AIDT - Just-In-Time Manufacturing - September 11, 2006                                     1
              Just-In-Time Manufacturing


                    FIGURE 1-10
                U-shaped Work Cells




     All the work to be done in this cell can be accomplished from a central
     area inside the U-shaped cell. Every production period can have varying
     numbers of operators. Six operators may be needed to produce 100
     parts in March, but if 50 parts are required in April a staff of three can
     theoretically produce those parts. When the operator does not have a
     full work load, the traditionalists have the operator go up or down the
     assembly line to the adjacent operation. In a U-shaped work cell, the
     operator has a full 360 degrees of mobility, therefore, he or she can
     perform all or part of tasks within the cell.

      In our example with three workers we show steps 1 and 6 to have a
     single operator, steps 2 and 5 have a single operator as do steps 3 and
     4. Another advantage of a U-shaped work cell is instantaneous quality

2                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                             Just-In-Time Manufacturing


                     control. Since parts are exiting one operation and migrating directly to
                     the next operation (if batch sizes are one), any deficiencies in quality
                     show up immediately. If a quality problem does occur it can be resolved
                     promptly. There are no large quantities of bad parts to sort through and
                     the need for separate inspection is eliminated.

                     U-shaped Cells Versus Assembly line Manufacturing

                     Traditional manufacturing operations are laid out in long, straight
                     assembly lines. The operators are spread along the line, thus, spreading
                     out the work. Since it takes longer for the product to travel from one
                     operation to the next, more parts must be put in the queue to keep
                     everyone busy. Unlike the U-shaped work cell, people are separated
                     from each other by the assembly line, inventory, work benches,
                     etc. Studies have also shown that physiological and psychological
                     disadvantages can occur from separating people in the work place.
                     Crew size is not flexible on an assembly line because the line has
                     been divided into an established number of separate areas. If an area
                     is missing an operator, the line will not run. Operators do not have the
                     flexibility to perform more than one task.
                      	
                     Comparisons of Assembly line and U-shaped Work Cell

                     Shown	 in	 Figure	 1-11	 (Black,	 34)	 is	 the	 metalworking	 facility	 that	
                     we	 discussed	 earlier	 in	 this	 manual.	 The	 departmental	 specialities	
                     have	been	dropped	in	favor	of	cellular	manufacturing.	A	much	more	
                     logical,	 organized	 approach	 to	 manufacturing	 is	 the	 result	 of	 this	
                     transformation.

                     Assembly Line                              Work Cell

             	       Uses	Much	Floor	Space	        	            Optimizes	Use	of	Floor	Space
             	   	   Operators	Separated	 	        	            Operators	Together
             	   	   Large	Batch	Sizes	 	          	            Small	Batch	Sizes
             	   	   Work	Spread	Out	     	        										   Work	Condensed
             	   	   Non-flexible	Crew	Size	       	            Flexible	Crew	Size
             	   	   Delayed	Quality	Control	      	            Instantaneous	Quality	Control
    	

AIDT - Just-In-Time Manufacturing - September 11, 2006                                          
       Just-In-Time Manufacturing


             FIGURE 1-11
     Cellular Manufacturing System




          AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


      I.     PUll SYSTEMS
             We are now ready to address pull systems, sometimes known as kanban
             systems or supermarket systems. The United States is in the process of phasing
             out the use of the word kanban due to its association with Japan. Kanban is
             not even a universally accepted Japanese term since some plants in Japan that
             compete with Toyota view it as a Toyota-coined word. For our purposes, we
             will use the term pull system.

             As mentioned earlier, Toyota sent representatives to the United States shortly
             after World War II to analyze our production techniques. They concluded
             that Americans ran their factories much the same way the Japanese ran their
             factories. Every operation in the factory works independently, then forces
             its parts onto the next operation. The Japanese termed this process a push
             system.

             1.     The Push System

                    A push system originates with a forecast schedule. This forecast is
                    forced upon the previous step (assembly) in the manufacturing process,
                    all the while adjusting for lead times to predict which subassemblies
                    are needed and by when. The subassembly forecasts are then forced
                    upon the various component levels still maintaining lead time, thus
                    completing the cycle through the total manufacturing system down to
                    raw materials. Paperwork accompanies this system informing operators
                    what is needed and by when.

                    Each operation then begins to manufacture parts and push them on
                    to the next operator. That operator receives the parts, does his work
                    and pushes them along the line. Operator 1 continues to work even if
                    operator 2 stops or is producing slower than operator 1. This extra
                    inventory creates buffers that hide manufacturing problems. (See
                    Figure 1-12). The expectation is that all this inventory will be pushed
                    along and will reach the predetermined places at the right time so as to
                    be shipped on schedule. Schedules are then analyzed to see what was
                    not on time and future schedules are adjusted accordingly.



AIDT - Just-In-Time Manufacturing - September 11, 2006                                    
                    Just-In-Time Manufacturing


                           FIGURE 1-12
                           Push System




                                OPERATOR 1
                           (50 PARTS PER HOUR)




          OPERATOR 2
     (30 PARTS PER HOUR)

6                         AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             2.     From Supermarket To Factory Floor - The Pull
                    System

                    While in America assessing our manufacturing processes, the Japanese
                    visited some of our supermarkets in their spare time. What they
                    learned and took back to Japan has revolutionized manufacturing. A
                    supermarket is managed very differently from a factory. Shoppers come
                    to a supermarket knowing that there will always be a small stock of
                    needed inventory. Customers feel no pressure to buy large quantities
                    because they know that the goods will be available when they need
                    them. Every night a “stocker” replenishes the inventory that has been
                    removed. Empty spaces on the shelves are the stocker’s signal to
                    produce more goods (restock). Exactly what has been taken is what is
                    replaced. The customers have directly told the store what to replace
                    by what has been purchased.

                    The	 Japanese	 converted	 this	 supermarket	 system	 for	 use	 in	 their	
                    factories.	 No	 operation	 can	 produce	 goods	 until	 it	 has	 received	 a	
                    signal	from	its		customers.	When	the	operator	gets	a	signal	from	the	
                    customer,	 he	then	has	 authorization	to	produce	a	certain	number	of	
                    parts	in	a	specific	time	period.	The	most	effective	pull	(kanban)	signals	
                    are	visual	indicators	such	as	empty	containers	or	empty	floor	space.		If	
                    you	have	an	empty	container,	fill	it	up;	if	you	have	no	container	then	
                    do	not	produce	that	part.		Other	types	of	signals	are	limited	only	by	the	
                    imagination.		They	may	include	such	things	as	color-coded	golf	balls,	
                    washers,	different	shaped	cards,	flashing	lights,	or	kanban	cards.	A	red	
                    golf	ball	may	signal	an	operation	to	produce	10	alphas	while	2	blue	
                    golf	balls	may	indicate	20	betas	are	needed.		The	most	used	signal	is	
                    a	kanban	card:

                                     FIGURE 1-13
                                     Kanban Card

    	 	      	      	      Part number 29AJ 087 	
                           Container 3 x 2 x 6 Box
                            20 	Pieces per container
                           Location		 Cell 2 			
                           Card 	 3 				of 	 5
AIDT - Just-In-Time Manufacturing - September 11, 2006                                       
             Just-In-Time Manufacturing


     The card tells what type of part to build, what to put the parts in, how
     many parts to build, where to send the parts and how many cards of
     these parts are required to maintain a smooth flow. Paper work is limited
     in a pull system.

     Imagine a company that makes a product line of alphas, betas, and
     gammas. Every day this company ships 20 percent alphas, 60 percent
     betas, and 20 percent gammas. Suppose the market (customer) demands
     more alphas and fewer betas on any given day. The only paperwork that
     needs to be changed is the shipping schedule. Shipping sends a signal
     to assembly to produce more alphas, while assembly sends a signal to
     subassembly for more alpha components, and on through the system to
     more alpha raw materials. No paperwork needs to be revised—it did
     not exist in the first place. Each previous operation is waiting to find
     out what parts to produce depending on customer needs.




                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    In an ideal JIT system, a pull signal is a compromise. If a true, one-at-
                    a-time flow has been implemented, no signal is needed. Figure 1-14
                    is what a model JIT pull system could look like.

                                    FIGURE 1-14
                        Production Control by Pull System




AIDT - Just-In-Time Manufacturing - September 11, 2006                                     
              Just-In-Time Manufacturing


     In the illustration, parts are flowing one at a time from the outside
     supplier (vendor) to the work cells. In these work cells there is no need
     for pull signals since the parts move one at a time from machine to
     machine. In an ideal JIT system the machines would be producing at
     the exact customer requirement rate (cycle time) and could change over
     as often as needed (level loading) for this rate. Parts would be pulled
     from cell to cell and then pulled to the subassembly cell. Subassembly
     would then have its parts pulled to assembly then to shipping and on
     to the final customer. This is a completely integrated manufacturing
     system where all parts are moving one at a time. Theoretically, this
     should be your end goal. But, while implementing JIT you will have a
     definite need for pull signals.

     When pull signals are needed, the key to making them work is making
     sure that the inventory is replenished frequently and quickly. This can
     only be accomplished after smaller batch sizes have been implemented
     through the use of Uniform Plant Loading. We must also remember
     that the smaller the batch sizes, the faster the setup must be. Just as in
     a supermarket, customers will be satisfied with taking small amounts
     if they know that there will be ample quantities available on the next
     shopping trip.

     Up to this point we have been talking about pull systems for repetitive
     manufacturing systems. Invariably the question comes up, “What about
     job shops?” To run a pull system in a job shop, where a completely
     different product is produced daily, monthly or yearly, the system must
     be managed differently. If a pull system is broken down to its purest
     form, the signal is an authorization to produce whatever is next in the
     queue. In a job shop the signal may stand for an hour’s worth of work.
     In effect, cell workers are saying, “An hour’s worth of work has been
     used up—so I am authorizing you to give me another hour’s worth of
     work.” Regardless of how you express it, the customer is telling the
     supplier what to do next.




0                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


      J.     JIT PURCHASING
             Probably no single group will conflict with the principles of JIT as much as
             the purchasing department. JIT purchasing is as different from traditional
             purchasing as JIT manufacturing is from traditional manufacturing. The goal
             of a purchasing department is the same as that for the manufacturing floor—the
             elimination of waste. Typical expenditures for a United States manufacturer
             are 70 percent purchased material and components, 10 percent labor, and 20
             percent overhead (Hay, 117).

                                     FIGURE 1-15
                            Typical Manufacturing Costs




             The fact that 70 percent of cost is purchased material reinforces the importance
             of total commitment to JIT by the purchasing department. This commitment
             will not be obtained unless the purchasing employees fully understand JIT
             principles because only then will they apply these principles to their purchasing
             processes.

AIDT - Just-In-Time Manufacturing - September 11, 2006                                      1
                     Just-In-Time Manufacturing


     Purchasing cost is a critical factor for a JIT manufacturing system, but it lags
     behind quality and delivery lead time in importance. Vendors must deliver
     quality products on time (just in time) before a JIT system can work, regardless
     of cost. JIT purchasing offers a framework for a true partnership between
     vendors and companies that helps to solve the problems of cost, quality and
     lead time.


     1.     Partnerships

            Traditional relationships between companies and vendors do not allow
            for partnerships to be formed. Companies send out bids for purchased
            materials with the contract going to the lowest bidder. Six months down
            the road another bid is let with the lowest bidder getting that contract.
            If the current vendor is not the lowest bidder that vendor may lose six
            months of business. Companies want vendors to cut their profits, but
            vendors need to be assured of a good profit now because they may not
            be here six months from now.

            The new JIT partnership that we are striving for is a long-term, mutually
            beneficial relationship with fewer but better vendors. Mutual trust
            must be developed between companies and vendors. This cannot be
            accomplished if vendors change every time new bids are sent out. For
            this reason a company should have few suppliers (preferably one) for
            each purchased material or component. This idea of single sourcing is
            as troublesome to traditional purchasing people as slower run speeds
            and smaller batch sizes are to traditional manufacturing people.

            Traditional purchasing people question whether the company is getting
            the best price possible by using only one supplier. As a company is
            reducing its vendors, it is obtaining the best price due to traditional
            competition. Vendors embrace the idea of a long-term relationship
            because it allows their sales to remain more constant. Strict criteria
            concerning dependability (quality and lead time) should be placed
            upon vendors by companies. When this criteria is satisfactorily met,
            the vendor will become “certified”. Ideally certified vendors deliver
            products just in time, every time, with 100 percent quality. A partnership
            is then formed between the company and the vendor so that they can
            actively work together to continually lower the cost of purchased
2                          AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    material. It would be impossible to form such relationships with several,
                    ever changing vendors.	

             2.     Eliminating Procurement Wastes

                    Three areas of waste need to be recognized before a company can
                    successfully implement JIT. First is the waste in a company’s own
                    manufacturing process: the moving, counting, rework, storing,
                    scheduling, setup times, and inspection. Secondly, waste within the
                    purchasing process itself should be eliminated. A third area that is
                    often overlooked is the manufacturing philosophy of a company’s
                    vendors. Since an average of 70 percent of a company’s costs come
                    from purchased materials, every company should aid its vendors in
                    eliminating waste in the vendor’s manufacturing process. However, it
                    should be stressed that a company must first get its own house in order
                    (eliminate waste) before the company can help its vendors to improve
                    their processes.

                     Let’s look at a few nonvalue-added steps (waste) in a typical component
                    before a value-adding process happens. A purchase order does not add
                    value, an amendment to a purchase order does not add value, reports
                    and invoices do not add value, taking something off a truck and putting
                    it in a holding area does not add value, inspecting it does not add value,
                    moving it to a stockroom does not add value, taking it from a large
                    container and placing it in a small container does not add value, and
                    moving it to where it is going to be used does not add value. The way
                    to eliminate waste is to eliminate all steps that do not add value to the
                    product.

                    The initial phase should be to delete inspection of all incoming raw
                    materials, parts, and components. This can be accomplished by
                    working with vendors to make sure they understand the process and
                    how to solve problems in the process. They should have a thorough
                    understanding of the standards that you require and have competent
                    inspection procedures so they can deliver 100 percent quality materials
                    and components. The eventual goal is for vendors to monitor rather
                    than inspect, with all operations done right the first time.	


AIDT - Just-In-Time Manufacturing - September 11, 2006                                      
                   Just-In-Time Manufacturing


     3.   A Day’s Worth Every Day

          In a repetitive manufacturing environment, the same amounts of
          inventory should be used up every day. Ideally materials and components
          will be delivered in the afternoon, used the next production day, and
          shipped the day after in the form of finished products. Packaging in this
          process does not add value, therefore reusable containers should be used
          to ship goods if possible. The vendor delivers goods to the production
          line and picks up empty containers for the next day’s shipment. These
          containers are the pull signal that tells the vendor to produce more, thus
          eliminating the need for purchase orders. Eliminating packaging cuts
          cost for the vendor and the company, causing the partnership between
          the two to be strengthened.

          Since these vendors are certified, there is no need for incoming
          inspection. A central holding dock or receiving area is not needed.
          There is no need for a stockroom or an inventory tracking system.
          There is no need for picking up and transporting. Purchase orders
          have been deleted. There are no corrugated boxes or excess paper to
          be ripped open and thrown away. And finally, no incoming invoices
          to be processed.

          Traditional purchasing personnel are probably yelling “What! No
          incoming invoice? How do we know what to pay and how do we know
          that we received everything?” Although a partnership must be built on
          trust, there is often no trust pertaining to money matters. The main proof
          of goods received is the shipping records. If two vendor components
          are needed for each product manufactured, you must deduce that if you
          shipped 100 products, you owe the vendor for 200 components. If the
          product was shipped, the components must have been in it.

          Of course, eliminating incoming invoices only works for a repetitive
          manufacturing facility, but all companies should question the way
          business is being conducted now. Every process in the purchasing
          department should be optimized through the use of JIT/TQM principles
          (teams, value-adding analysis, cross-training, etc.). Companies must
          strive to form a long-term, mutually beneficial partnership with vendors
          that is built on trust. Traditional methods of purchasing will no longer
          apply in the new JIT environment.
                        AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


      K.     JIT IN CoNJUNCTIoN WITH MANUFACTURING
             RESoURCE PlANNING
             JIT and MRP—friends or foes? Many have debated the comparative benefits
             of JIT and MRP. To put this controversy to rest, we must have a better
             understanding of what MRP is and how it can be used with JIT to achieve
             greater results than if either technique were used alone. MRP I (Material
             Requirement Planning) and MRP II (Manufacturing Resource Planning)
             evolved in the United States in the early 1960s. MRP II is the combination of
             various manufacturing tools collected to form the most sophisticated planning
             and scheduling strategy developed to date. These tools are Reorder Point
             (ROP), Economical Order Quantity (EOQ), Material Requirement Planning
             (MRP I), Distribution Requirement Planning (DRP), Capacity Requirement
             Planning (CRP), Shop Floor Control (SFC), and others. For the purpose of
             this manual, MRP will refer to Manufacturing Resource Planning (MRP II).

             Many MRP software companies fail to comprehend the overall picture,
             resulting in the misconception that JIT will cut into their market share. The
             MRP gurus tend to view only parts of the whole so that they fail to address
             the manufacturing process and master the usefulness of both systems. JIT and
             MRP can and do work well together, but we must be conscious of the fact that
             MRP wants to work with the scheduling system while JIT wants to radically
             alter the manufacturing process.

             1.     Which System?

                    Many companies question whether to use JIT or MRP or both and if they
                    use both, which strategy should they implement first. If your company
                    has deteriorated greatly, it may be easier to implement a MRP system.
                    The MRP system will allow you to get your process under control
                    without radically changing your manufacturing process. If the company
                    is fundamentally sound, a JIT system should be implemented first. If
                    after JIT is in place it is decided to have a more formal scheduling
                    system, less time and money are required to implement a simplified
                    MRP system. This hybrid system can then be used to form an enhanced
                    manufacturing system.



AIDT - Just-In-Time Manufacturing - September 11, 2006                                  
             Just-In-Time Manufacturing


     Under a traditional MRP system there are three levels of scheduling
     (Hay, 155):
     •     Master Schedule – quantity and date for completion of end
           items.

     •      Material Requirements Planning – scheduling the completion
            and start dates of the components and raw materials dependent
            on the master schedule.
     •      Shop Floor Control – scheduling the operations performed on
            a component between MRP start and finish dates; often called
            “priority sequencing”.

     The hybrid system where JIT and MRP are working together eliminates
     the need for Shop Floor Control since parts flow from start to finish
     without being warehoused. MRP I becomes more basic since parts go
     directly to the next user without traveling in and out of stock. Also,
     remember that batch sizes are smaller or nonexistent, safety stock has
     been eliminated, throughput has been speeded up and production rate
     equals the customer requirement rate via the JIT segment of this hybrid
     system.

     No matter how complex the manufacturing process, as lead time
     diminishes, the need for MRP reduces. MRP becomes increasingly
     simplified and acts as the transition tool until its scheduling function
     disappears as linking operations become feasible. In some job shop
     situations implementing JIT fully may be impossible, thus opening the
     door for this hybrid system. Even in an ideal JIT system, the benefits
     of MRP cannot be ignored.




6                   AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


      l.     MANAGEMENT'S RESPoNSIbIlITY
             The predominant reason for JIT failure is lack of commitment by top
             management. JIT must be launched where there is absolutely no skepticism
             about management’s long-term commitment to JIT success. Employees recall
             management’s past track record on “flavor of the month plans” that died quietly
             with little or no fanfare. The first time management compromises quality in
             favor of quantity it will devastate the morale of the shop floor personnel. They
             sense that management’s main emphasis is money for products shipped, not
             customer satisfaction, thus relegating JIT to a quiet death.

             JIT must have a champion for its cause within every organization. Ideally, this
             advocate would be the highest ranking person who applies to your situation,
             i.e., the CEO at the corporate level, the division manager at the division level
             or the plant manager at the plant level. Typically, the consciousness of JIT
             penetrates the organization somewhere below this top level of management.
             For the greatest chance of success, JIT should be presented to the top manager
             as soon as possible. By initially teaming up with the top manager, he or she
             will perceive ownership of the JIT concept, thus he or she will have a stronger
             commitment to JIT. If the top management does not embrace the concept of
             JIT, but rather it develops at the middle management level, the chance for
             failure increases.

             There are two key elements that are management's responsibility: motivation
             and education. Management must use these elements to overcome the
             reluctance to change by the employees and the natural fear that accompanies
             change. Each level of the organization has different fears about JIT so each
             level requires a different motivational approach. Management must understand
             the apprehensions of people at every level and what actions can be taken to
             gain their trust and commitment to join the JIT venture.




AIDT - Just-In-Time Manufacturing - September 11, 2006                                     
                  Just-In-Time Manufacturing


     1.   Motivation

          Top	managers	should	already	be	motivated	by	what	they	see	as	JIT’s	
          ability	to	produce	more	efficiently.	

          Upper	 and	 middle	 managers	 often	 feel	 they	 are	 caught	 between	 a	
          rock and a hard place. Top management is angry because JIT is not
          progressing fast enough and the shop floor employees are mad because
          they cannot perform the JIT miracles that middle management expects
          of them. Middle managers have worked hard to gain the status that
          they now have and feel threatened by the new JIT style. The means
          to conquer these fears is trust. Middle management can be motivated
          by knowing that top management is 100 percent dedicated to JIT, and
          that top management is aware of the problems and will help solve
          these problems. Finding these solutions often is not easy, but can be
          accomplished by a motivated management staff working closely with
          top management.

          Why is motivating the shop floor personnel so difficult? Isn’t JIT
          involving them more in the decision making process and making
          their jobs much easier? Until now shop floor personnel have made no
          decisions, therefore have taken no risk of making the wrong decision.
          Management must motivate these people by assuring them that
          making a wrong decision is permissible as long as they learn from it.
          Shop floor personnel also have major concerns about job security. If
          operators are doing their own setups, where do the setup people go?
          If top management says that everyone is responsible for quality, do the
          quality control people lose their jobs? Top management should calm
          these fears through a no-layoff guarantee. Management should also
          form a partnership with all employees to earn their trust and motivate
          them by communicating to them that the whole organization must
          change, not just the shop floor personnel.

     2.   Training

          Management must convey to all employees why the organization is
          being restructured. If the company is in trouble, management should
          be honest with the employees. All employees should be trained in

                        AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    the reasons for and methods of JIT. Employees are more receptive
                    to JIT if they understand how pull systems, setup reduction, reduced
                    inventory, plant loading, shorter lead times, better quality, etc., can
                    lead to a larger market share, higher sales, and increased customer
                    satisfaction. Management should devise a structured approach for
                    training all employees in the principles of JIT. An employee in
                    purchasing may not need to know how to reduce setup time on a
                    particular machine but must know why this time must be reduced.

                    Management must also participate in training. Other than a complete
                    understanding of JIT principles, managers will need training in
                    “modern” management techniques, such as Total Quality Management
                    (TQM). Managers must develop the total quality mindset that will
                    allow them to lead the organization into JIT.

             3.     leadership

                    Management must realize that actions speak louder than words. Any
                    conflict between management’s words and management’s actions
                    will be noticed by employees. If management feels that training is
                    important but misses a training session in favor of a “higher priority,”
                    it has sent a negative message to the employees. Top management
                    must demonstrate its commitment to JIT through long hours and hard
                    work. Management’s actions should build employee trust, and trust is
                    the most important element of any plan.

      M.     IMPlEMENTING JIT
             JIT implementation must start by creating a suitable environment for JIT to
             flourish. A structure must be established whereby responsibility for problem
             solving is appropriated to all levels of the organization. Shop floor personnel
             will be asked to find solutions for shop floor problems and so on throughout
             the organization. This reversal from traditional management style to a Total
             Quality Management (TQM) style can only be accomplished through Total
             Employee Involvement (TEI) and employee teams. TQM is a prerequisite to
             JIT.



AIDT - Just-In-Time Manufacturing - September 11, 2006                                    
                   Just-In-Time Manufacturing


     1.   Forming Teams

          The first team that should be established is the quality team sometimes
          called the Executive Council or Quality Steering Committee. No matter
          what you call it, the objectives of the top team will be the same. The
          Steering Committee will address the issues with TQM implementation
          (you are not ready for JIT yet) while attending to everyday organizational
          issues as well. If possible, Steering Committee members should be
          removed from the interruptions of everyday organizational decisions.
          It is a proven fact that companies that allow their Steering Committees
          to dedicate all their time to solving TQM/JIT implementation problems
          have higher success rates and shorter implementation times.

          The Steering Committee will be made up of high ranking officials
          within the organization. They will assign teams from the workforce to
          solve various implementation problems. The employees that constitute
          these teams now have the power to make decisions that directly affect
          productivity at their level. Team logistics will not be discussed in this
          manual.

     2.   Developing A JIT Strategy

          Now that you understand the basics of JIT, a specific implementation
          strategy must be developed. There are no cookbook solutions for JIT
          implementation. Each Steering Committee has a different vision
          and each company goes about implementation differently. Below are
          examples of how JIT has been successfully applied in various types
          of organizations.

          •      Company 1 concentrated on finding the bottleneck in its
                 manufacturing process and worked to eliminate it through
                 reducing setup times, forming machine cells, removing
                 nonvalue-added steps, or whatever means required. After each
                 bottleneck had been eliminated, the company found the next
                 largest bottleneck and eliminated it, and so on, throughout the
                 entire organization. Employees are still finding bottlenecks
                 (albeit much smaller ones), and will continue to do so through
                 the process of continuous improvement.


0                        AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


                    •      Company 2 implemented JIT at its final operation and progressed
                           in reverse order throughout the plant until reaching incoming
                           raw materials. The idea behind this strategy is that as you
                           implement JIT, you eliminate the need for excess inventory for
                           the succeeding process or processes down the line. Suppose a
                           plant has nine operations to perform before a part is shipped. If
                           you optimize step nine first, parts can be pulled from step eight
                           to step nine after eight has been optimized. When you reach step
                           five, parts will flow from five to nine in a true JIT fashion.

                    •      Company 3 started by removing as many nonvalue-adding steps
                           from the manufacturing process as possible without moving any
                           machines. Employee teams solved as many problems as they
                           could while leaving machines in the traditional configuration.
                           Machines were then relocated into cells and the teams went
                           back to work to eliminate waste in the new configuration. The
                           teams will now continually move machines and optimize the
                           process.

                    •      Opposite to company 3, company 4’s Steering Committee
                           moved machines into cells to improve product flow. Employee
                           teams were then tasked with removing as much waste from the
                           process in the current configuration. When teams recommended,
                           machines were moved again. Company 4 moved machines
                           frequently while company 3 rarely moved machines.

                    •      Company 5 used what we will call the shotgun approach.
                           Teams were tasked with implementing JIT as fast as possible
                           with no visible structured approach. Machines were moved and
                           inventory reduced and then it was up to the teams to implement
                           JIT. Problems were solved on a priority basis as determined
                           by the Steering Committee. A word of warning: this approach
                           cannot happen if quality will not allow smaller inventories.
                           On the positive side, employees were assured of management’s
                           commitment because the conversion to JIT happened fast.




AIDT - Just-In-Time Manufacturing - September 11, 2006                                    1
                         Just-In-Time Manufacturing


                •      Similar to company 2, company 6 initiated JIT one cell at a
                       time, but not at the last operation. Pilot projects were selected
                       by the Steering Committee on the basis of success probability.
                       Since the pilot project set the tone for the entire JIT effort, a
                       project was chosen that would get the best results. Company
                       6 continued to add projects until the entire organization was
                       converted to JIT.

                These six companies used six comparable but different approaches
                to achieve the same results. You may choose a method similar to one
                of these, a combination of these, or a completely different method to
                implement JIT. How you accomplish JIT is not as important as when
                you do it.

     N.   GloSSARY
          Batch Size – The number of duplicate parts, components or finished goods
          produced before a process is changed to produce different parts. Also known
          as Lot Size.

          Changeover Time – The time it takes to go from production of one product to
          production of a different product with acceptable quality, i.e., Setup Time.

          Cross-training – Educating employees to perform more than one job,
          therefore, increasing flexibility in the workforce.

          CRP – Capacity Requirement Planning

          Cycle Time – The total time for a worker to complete one cycle of operations,
          including walking, loading/unloading, inspecting, etc.

          EOQ – Economical Order Quantity

          External Customer – A person who has purchased a product from a company;
          usually the end user of a product.

          External Setup – Setup steps done while the machine or system is
          producing.

2                              AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             Flexible Changeover – The capability to manufacture what you want, when
             you want, in whatever batch size you require.

             Heisenberg Principle – The idea that a phenomenon that is observed is
             changed merely by the fact that it is being observed.

             Internal Setup – Setup steps done only when the machine or system is
             idle.

             Internal Customer – The next person or process that receives product from
             a preceding process within an organization, i.e., the next person down the
             line.

             JIT (Just-In-Time) – Producing the minimum number of units in the smallest
             possible quantities at the latest possible time, which in turn eliminates the need
             for inventory. Such production reduces waste and improves quality.

             Job Shop – An organization that produces short runs of similar parts and
             specialized one-of-a-kind parts.

             Kanban – Any visual device that strictly limits length of a waiting line
             (inventory) and authorizes work. An example of this is a kanban card.

             Level Loading – The production of products at the proper frequency. Products
             are made at the customer requirement rate. In theory, if a product is sold every
             day, it should be made every day.

             Machine Cell – Machines grouped together for the purpose of producing a
             product one at a time from machine to machine while having the flexibility
             to produce different products and operate at different output rates and with
             different crew sizes (cycle time). Also known as work cells.

             Malcolm Baldrige National Quality Award – Annual award recognizing U.S.
             companies that excel in quality achievement/management. Founded in 1987 and
             administered by Department of Commerce’s Technology Administration.




AIDT - Just-In-Time Manufacturing - September 11, 2006                                       
                    Just-In-Time Manufacturing


     MRP I (Material Requirement Planning) – Scheduling the completion and
     start dates of components and raw materials.

     MRP II (Manufacturing Resource Planning) – Arranging material
     requirements while maintaining the due date for each component supply order
     so that each order will arrive just in time for the next process.

     Nonvalue-adding Operation – A function that adds cost to a product, not
     value; such as inspecting or moving.

     Pareto Chart – A bar chart that arranges data in order of importance. The bar
     representing the item that occurs or costs most is placed on the left-hand side
     the horizontal axis. The remaining items are placed on the axis in descending
     order. Typically a few causes account for most of the output; hence the phrase
     “vital few and trivial many”.

     Poka-yoke – Devices used to prevent defects from occurring in the
     manufacturing process. Also known as fail-safing or fool-proofing.

     Process – Any set of conditions or causes working toward an outcome.

     Pull System – The manufacturing process whereby each operation uses parts as
     needed, therefore releasing a production authorization signal to the preceding
     operation. No parts are produced until needed and no extra parts are produced.
     Also called the supermarket system or kanban system.

     Push System – The manufacturing process by which each operation works
     independently and “pushes” its parts on to the next operation by a certain
     date.

     Quality – Fitness for use. Product performance resulting in customer
     satisfaction. Freedom from product deficiencies which avoids customer
     dissatisfaction.

     Repetitive manufacturing – The process in which large numbers of the same
     parts or family of parts are made.

     ROP – Reorder Point

                          AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             Setup Time – The interval between the production of one good part and the
             production of another good but dissimilar part.

             SFC (Shop Floor Control) – Scheduling the operations performed on
             a component between MRP II and finish dates; often called priority
             sequencing.

             SMED – Single-Minute Exchange of Die – A procedure for performing setup
             operations in less than 10 minutes, i.e., in a single-digit number of minutes.
             Not all setups can be completed in single-digit minutes, but this is the goal.

             SPC (Statistical Process Control) – A method of managing a process by
             gathering information about it and using that information to correct the process
             to prevent the same problem from happening again.

             System – Any organizational method, procedure or function for accomplishing
             work.

             Takt Time – The total daily operating time divided by the total daily
             requirement, usually expressed in hours, minutes or seconds per part.

             TEI (Total Employee Involvement) – 100% of workforce is placed on teams
             formed to continuously improve quality in all aspects of an organization.

             TQM – Organized, continuous process improvement activities involving
             an entire organization, managers and workers, in a totally integrated effort
             to improve performance at every level focusing on customer satisfaction
             (quality).

             Value-adding Operation – A function that adds value to a product, such as
             milling and assembling.

             Value Analysis – A process for evaluating the interrelationships among the
             functions performed by the product features and the associated costs.

             Vendor Certification – The procedure by which a partnership is formed
             between the buyer and seller of a product. Strict criteria are established for
             the seller and when these criteria are met the seller becomes certified.

AIDT - Just-In-Time Manufacturing - September 11, 2006                                     
                         Just-In-Time Manufacturing


          Waste – Anything other than the minimum amount of equipment, materials,
          parts, space and worker time, which are absolutely essential to production.

          WIP – Work-In-Process

          Xeno’s Paradox – A mathematical paradox which states that if a person walks
          toward a wall, each step being half as large as the previous one, that person
          will never reach the wall.

          Zero Defects (Zero Quality Control) – The objective of defect-free production
          where zero defects is defined as meeting product specifications.

     o.   REFERENCES AND RECoMMENDED READINGS
          The Design of a Factory with a Future
          by J.T. Black
          Director of Advanced Manufacturing/Technology Center Auburn University

          Copies are available from the publisher (or by calling 1-800-334-7344):
          McGraw Hill Book Company
          P.O. Box 18122
          Newark, N.J. 07191
          Library of Congress Catalog Number: 90-19991
          ISBN: 0-07-005551-3 (hard cover)
                 0-07-005550-5 (soft cover)

          Introduction to TPM: Total Productive Maintenance
          by Seiichi Nakajima

          Copies are available from the publisher (or by calling 1-800-274-9911):
          Productivity Press, Inc.
          P.O. Box 3007
          Cambridge, MA 02140        (617) 497-5146
          Library of Congress Catalog Card Number: 88-61394
          ISBN: 0-915299-23-2




6                              AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             Juran’s Quality Control Handbook
             by J.M. Juran

             Copies are available from the publisher (or by calling 1-800-952-6587):
             American Society for Quality Control (ASQC)
             Customer Service Department
             P.O. Box 3066
             Milwaukee, WI 53201
             Library of Congress Catalog Card Number: 86-18762
             ISBN: 0-13-1983441-1

             The Just-In-Time Breakthrough
             Implementing the New Manufacturing Basics
             by Edward J. Hay

             Copies are available from the publisher (or by calling (212)850-6354):
             John Wiley and Sons
             Business/Law/General Books Division
             605 Third Avenue
             New York, N.Y. 10158-0012
             Library of Congress Catalog Card Number: 87-25315
             ISBN: 0-471-85413-1

             Just-In-Time: Alive and Well in the South
             by Dr. Anthony Inman
             Article published in Southern Business and Economic Journal, April 1991,
             Vol. 14, No, 3, 155-167.

             Out of the Crisis
             by Edward Deming

             Copies are available from the publisher (or by calling 1-800-952-6587):
             American Society for Quality Control (ASQC)
             Customer Service Department
             P.O. Box 3066
             Milwaulkee, WI 53201
             Library of Congress Catalog Card Number: 86-18762
             ISBN: 0-13-198441-1

AIDT - Just-In-Time Manufacturing - September 11, 2006                                 
                    Just-In-Time Manufacturing


     Poka-yoke: Improving Product Quality By Preventing Defects
     by Hiroyuki Hirano

     Copies are available from the publisher (or by calling 1-800-274-9911):
     Productivity Press, Inc.
     P.O. Box 3007
     Cambridge, MA 02140        (617) 497-5146
     Library of Congress Catalog Card Number: 88-62593
     ISBN: 0-915299-31-3

     Quality Without Tears
     by Phillip Crosby

     Copies are available from the publisher (or by calling 1-800-952-6587):
     American Society for Quality Control (ASQC)
     Customer Service Department
     P.O. Box 3066
     Milwaulkee, WI 53201
     Library of Congress Catalog Card Number: 86-18762
     ISBN: 0-13-198441-1

     Reinventing the Factory:
     Productivity Breakthroughs in Manufacturing
     by Roy L. Harmon and Leroy D. Peterson

     Copies are available from the publisher (or by calling 1-800-274-9911):
     Productivity Press, Inc.
     P.O. Box 3007
     Cambridge, MA 02140,       (617) 497-5146
     Library of Congress Catalog Card Number: 88-62593
     ISBN: 0-915299-31-3




                         AIDT - Just-In-Time Manufacturing - September 11, 2006
                            Just-In-Time Manufacturing


             A Revolution In Manufacturing: The SMED System
             by Shigeo Shingo

             Copies are available from the publisher (or by calling 1-800-274-9911):
             Productivity Press, Inc.
             P.O. Box 3007
             Cambridge, MA 02140,       (617) 497-5146
             Library of Congress Catalog Card Number: 84-61450
             ISBN: 0-915299-03-8

             Statistical Process Control Methods
             by Gary K. Griffith

             Copies are available from the publisher (or by calling 1-800-952-6587):
             American Society for Quality Control (ASQC)
             Customer Service Department
             P.O. Box 3066
             Milwaukee, WI 53201
             Library of Congress Catalog Card Number: 86-18762
             ISBN: 0-13-198441-1

             The Team Handbook
             by Peter Scholtes

             Copies are available from the publisher (or by calling 1-80-952-6587):
             American Society for Quality Control (ASQC)
             Customer Service Department
             P.O. Box 3066
             Milwaukee, WI 53201
             Library of Congress Catalog Card Number: 86:18762
             ISBN: 0-13-198441-1

             Training: Quality Supplement. "Is 99.9% Good Enough"
             by Natalie Gabel
             March, 1991. 40-41.




AIDT - Just-In-Time Manufacturing - September 11, 2006                                 
                    Just-In-Time Manufacturing


     World Class Manufacturing: The Lessons Of Simplicity Applied
     by Richard J. Schonberger

     Copies available from the publisher (or by calling 1-800-274-9911):
     Productivity Press, Inc.
     P.O. Box 3007
     Cambridge, MA 02140,       (617) 49705146
     Library of Congress Catalog Card Number: 85-24719
     ISBN: 0-02-929270-0

     World-Class Manufacturing Casebook: Implementing JIT and TQC
     by Richard J. Schonberger

     Copies available from the publisher (or by calling 1-800-274-9911):
     Productivity Press, Inc.
     P.O. Box 3007
     Cambridge, MA 02140         (617) 49705146
     Library of Congress Catalogue Card Number: 86-25822
     ISBN: 0-02-920340-5

     JIT Factory Revolution:
     A Pictorial Guide to Factory Design of the Future
     by Hiroyuki Hirano

     Copies available from the publisher (or by calling 1-800-274-9911):
     Productivity Press, Inc.
     P.O. Box 3007
     Cambridge, MA 02140,       (617) 49705146
     Library of Congress 88-29007
     ISBN: 0-915299-44-5




60                         AIDT - Just-In-Time Manufacturing - September 11, 2006

				
DOCUMENT INFO
Shared By:
Tags:
Stats:
views:16
posted:11/28/2012
language:Unknown
pages:63