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					Cellular Manufacturing
   and Facilities Layout

       Dr. Richard A. Wysk
          rwysk@psu.edu
   http://www.engr.psu.edu/cim
           Outline of Activities
•   Fundamentals of layout
•   Advantages of various layouts
•   Creating part families
•   Economics of Cellular layout
    – scheduling
    – setup reduction
• Other issues
                    Readings
• Chapter 18 of Computer Aided Manufacturing, Wang,
  H.P., Chang, T.C. and Wysk, R. A., 3rd Edition (2004
  expected)
  http://www.engr.psu.edu/cim/active/chapter18.pdf
                   Exercise
    Readiness Assessment Test          A.K.A. RAT


 AS AN INDIVIDUAL,
Describe what you think a “part family” is.
Describe what you think a “process family” is.
Which is the best way to cluster products in a
 manufacturing facility: a) the way a part
 looks, b) the function of the part, 3) the way
 the part is made. Why?

              Open Book / Open Notes
                         Exercise
     Readiness Assessment Test                   A.K.A. RAT


  AS A TEAM, take 5 minutes

• Compare and discuss the efficiencies and the uses of the
  various ways to group “stuff” in a shop.
• Try to chalk out a „best practice‟.
• List the criterion you used.


                        Open Book / Open Notes
              Objectives
• To apply the principles of flow to a
  complex manufacturing system
• To design the layout of process, product
  and cellular manufacturing systems
• To form cells in a manufacturing
  environment
• To analyze efficiencies of reduced batch
  sizes
 Types of Manufacturing Layout
• Process Layout
• Product Layout
• Cellular Layout
FUNCTIONAL LAYOUTS ARE INEFFICIENT

     Lathe             Milling            Drilling
 L           L    M              M    D              D

                                      D              D
 L           L    M              M
                                      Grinding
 L           L    M              M    G              G

                       Assembly
 L           L                        G              G
                   A              A
Receiving and      A              A   G              G
  Shipping


             PROCESS-TYPE LAYOUT
  Process Layout Characteristics
• Advantages
  – Deep knowledge of the process
  – Common tooling and fixtures
  – Most Flexible -- can produce many different part types
• Disadvantages
  –   Spaghetti flow -- everything gets all tangled up
  –   Lots of in-process materials
  –   Hard to control inter-department activities
  –   Can be difficult to automate
                  PRODUCT LAYOUT
Part #1     L       L     M   D   G

                                      A         A
Receiving           L     M   G   G
                Part #2
            L       M     D               Shipping
Part #3
 Product Layout Characteristics
• Advantages
  – Easy to control -- input control
  – Minimum material handling -- frequently linked to the
    next process
  – Minimal in-process materials
  – Can be more easily automated
• Disadvantages
  – Inflexible -- can only produce one or two parts
  – Large setup
  – Duplicate tooling is required for all cells
                          CELLULAR LAYOUT
            Cell #2                         Cell #1

    D          D           M       I        D
                                                      I
                                             L
            Cell #3
                                                      M
                                             M
L       L             D        M       I
 Cellular Layout Characteristics
• Advantages
  – Control is simplified
  – Common tooling and fixtures
  – Flexible -- can produce many different part types - a
    part family??
• Disadvantages
  – Setup ??
  – Need to know about many different processes
  HIGH

         TRANSFER
           LINE

               SPECIAL
VOLUME




               SYSTEM
                           FLEXIBLE
                         MANUFACTURING
                            SYSTEM

                                 MANUFACTURING
                                      Cells

                                         STD. AND GEN.
                                          MACHINERY

 LOW                                                     HIGH
                         VARIETY
           How are Cells Formed
•   Good intuition
•   Careful study
•   Group Technology (GT)
•   Production Flow Analysis (PFA)
Typical Part Families
     Items that are made with the same equipment
     Items that look alike




        A FAMILY OF PARTS
PRODUCTION
  FAMILY
  Items that are made with the same
equipment - Production Flow Analysis
PFA is a technique that uses Operation
  Routing Summaries as input. It clusters the
  parts that require the same processes. These
  parts can then be assembled into a part
  family. The processes can be grouped into
  a cell to minimize material handling
  requirements.
       Items that look alike
Most products that look similar are
 manufactured using similar production
 techniques. If parts are grouped because
 they have similar geometry (about the same
 size and shape), then they should represent
 a part family.
Grouping based on geometry or
          function
THREE TECHNIQUES TO FORM PART FAMILIES

1. TACIT JUDGMENT OR VISUAL INSPECTION

      • MAY USE PHOTOS OR PART
         PRINTS
      • UTILIZES SUBJECTIVE
         JUDGMENT

2. CLASSIFICATION & CODING BY EXAMINTAION
      OF DESIGN & PRODUCTION DATA

        • MOST COMMON IN INDUSTRY
        • MOST TIME CONSUMING &
             COMPLICATED
                                 Cont‟d
THREE TECHNIQUES TO FORM PART FAMILIES



 3. PRODUCTION FLOW ANALYSIS
     • USES INFORMATION CONTAINED
         ON THE ROUTE SHEET
         (THEREFORE ONLY MFG. INFO)
     • PARTS GROUPED BY REQUIRED
         PROCESSING
Classification & Coding by Examination of
         Design & Production Data


  Many systems have been developed but
  none is universally applicable and most
  implementations require some
  customization
Identifying Manufacturing Cells
Using Production Flow Analysis
Production Flow Analysis
• A technique for forming part families based on Operation
  Routing Summaries
• Several methods available. We will discuss 2 algorithms for
  PFF (Part Family Formation)
Let‟s consider 5 parts (n) and 6 machines (m):


n = {101, 102, 103, 104, 105}
m = {Drill1, Drill2, Mill1, Mill2, Vbore1, Vbore2}
  = {D1, D2, M1, M2, V1, V2}
           Operation Routing Summary

Part No.     Routing       Times (min)    Ave. Dem.
  101       D1 -M1 - V1     9 - 12 - 14      100
  102       D2 -M2- V1      5 - 11 - 14      250
  103         D1 -M1           7-9           700
  104       M2 - V2 - D2    8 - 12 - 5       100
  105       V1 - M1 - D1    7 - 10 - 12      200
 Create a PFA matrix, M


                                         Parts
                             101   102      103   104   105
                    Drill1    1     0        1     0     1
         Machines


                    Drill2    0     1        0     1     0
                    Mill1     1     0        1     0     1
M =                 Mill2     0     1        0     1     0
                    VB1       1     1        0     0     1
                    VB2       0     0        0     1     0
     King’s Algorithm (Rank Order Clustering)
                  Step#1
                  Calculate the total column width for each column
                                                                   Generate 2i
                                         wj =    2 mi   i

                                                "i


Machine#    (i)   Part# (j)   101   102    103       104     105             i
                                                                         2
        1         D1          1     0      1         0       1           2
        2         D2          0     1      0         1       0           4
        3         M1          1     0      1         0       1           8
        4         M2          0     1      0         1       0           16
        5         V1          1     1      0         0       1           32
        6         V2          0     0      0         1       0           64
Sum: mi,j * 2i                42    52     10        84      42   (wj)
for each column (wj)
#2.   If Wj is in ascending order, go to step #3; otherwise,
      rearrange the columns to make Wj fall in an ascending order.

                           101    105


                     103   101   105     102   104
                                                     i
                D1    1     1     1       0     0    14
                D2    0     0     0       1     1    48
                M1    1     1     1       0     0    14
                M2    0     0     0       1     1    48
                V1    0     1     1       1     1    28
                V2    0     0     0       0     0    32
               wj    10    42    42      52    84

                                       102

                     103                       104
        #3. "i, calculate the total row weight, wi


                           wi =   2 m
                                   "j
                                         j
                                              ij
                                                         Sum: mi,j * 2j
                                                          for each row (wi)
                     103   101    105   102   104   wi
               D1     1     1      1     0      0   14
               D2     0     0      0     1      1   48
               M1     1     1      1     0      0   14
               M2     0     0      0     1      1   48
               V1     0     1      1     1      1   28
Generate 2j    V2     0     0      0     0      0   32
               2j    2     4      8     16     32
#4.    If wi is in ascending order, stop. Otherwise, arrange
rows to make Wi ascend.



             103     101     105     102     104
              1       1       1       0       0      D1
              1       1       1       0       0      M1        M1
              0       1       1       1       0      V1   V1
              0       0       0       0       1      V2
              0       0       0       1       1      D2             D2 V
              0       0       0       1       1      M2                 2
                                                          V2
#5 Stop and make Cells and Part families



    103    101     105    102     104
     1      1       1      0       0       D1
     1      1       1      0       0       M1
     0      1       1      1       0       V1
     0      0       0      0       1       V2
     0      0       0      1       1       D2
     0      0       0      1       1       M2
Discussion
•   Good rectangles mean that you have very distinctive part families
•   Do Parts no 103, 101, 105 have a distinct code so that a F can be
    made to distinguish them from #102, 104.
•   Cell formation
•   Volume / Floor space
•   Size of problems
•   How about King‟s algorithm? Will it always work?
•   Are there problems with it?
                 DIRECT CLUSTER
                   ALGORITHM
                  101      102   103          104   105   wi
           D1     1        0     1            0     1     3
           D2     0        1     0            1     0     2
           M1     1        0     1            0     1     3
           M2     0        0     0            1     0     1
           V1     1        1     1            0     1     4
           V2     0        0     0            1     0     1




Step #1.   For   I,   calculate the total no. of positive cells in row, i
                              wi =
                                      M ij
                                     a ll j
    Sort rows in descending order of the wi values



               101   102   103   104   105   wi
   D1    V1    1     1     1     0     1     4
         D1    1     0     1     0     1     3
D2    V1 M 1   1     0     1     0     1     3    No Change
         D2    0     1     0     1     0     2
   M2    M2    0     0     0     1     0     1
         V2    0     0     0     1     0     1    No Change
               3     2     3     3     3     1
Step #2.    j,calculate the total # of positive cell in each
           column, j



                          wj =   m
                                  alli
                                         ij
 Sort columns in ascending order.



      101   102   103   104   105
V1    1     1     1     0     1
D1    1     0     1     0     1
M1    1     0     1     0     1
D2    0     1     0     1     0
M2    0     0     0     1     0
V2    0     0     0     1     0
      3     2     3     3     3
Step #3.   For i = 1 to n, move all columns j where mij = 1 to the left
           maintaining the order of previous rows.


                    Observe Elements of Row 1

                      102   101   103    104    105
               V1     1     1     1      0      1
               D1     0     1     1      0      1
               M1     0     1     1      0      1
               D2     1     0     0      1      0
               M2     0     0     0      1      0
               V2     0     0     0      1      0


           Move Column 105 to the left and push column 104 back
For Rows 1,2 & 3: Move the 1’s to the left and push the columns with
the zeroes back



                  Observe Elements of Rows 2 & 3

                   102   101     103    105   104
             V1    1     1       1      1     0
             D1    0     1       1      1     0
             M1    0     1       1      1     0
             D2    1     0       0      0     1
             M2    0     0       0      0     1
             V2    0     0       0      0     1



    Move Columns 101, 103 & 105 to the left and push column 102 back
         Observe Elements of Row 4


           101    103   105   102   104
    V1     1      1     1     1     0
    D1     1      1     1     0     0
    M1     1      1     1     0     0
    D2     0      0     0     1     1
    M2     0      0     0     0     1
    V2     0      0     0     0     1


Move Column 102 to the left and push column 101 back
         Observe Elements of Rows 5 & 6


         102   101   103   105    104
    V1   1     1     1     1      0
    D1   0     1     1     1      0
    M1   0     1     1     1      0
    D2   1     0     0     0      1
    M2   0     0     0     0      1
    V2   0     0     0     0      1


Move Column 104 to the left and push column 102 back
     104   102   101   103   105
V1   0     1     1     1     1
D1   0     0     1     1     1
M1   0     0     1     1     1
D2   1     1     0     0     0
M2   1     0     0     0     0
V2   1     0     0     0     0
 Step #4.       For j = m to 1, move all rows I, where mij = 1 to
 the top maintaining the order of the previous columns, wij

Observe Elements of Columns 101, 103 & 105: No Change can be made!!
             Observe Elements of Column 102

                  104   102   101   103   105
            V1    0     1     1     1     1
            D1    0     0     1     1     1
            M1    0     0     1     1     1
            D2    1     1     0     0     0
            M2    1     0     0     0     0
            V2    1     0     0     0     0



         Move Row D2 upwards and push row D1 down
  Observe Elements of Column 104

          104   102   101   103   105
   V1     0     1     1     1     1
   D2     1     1     0     0     0
   M1     0     0     1     1     1
   D1     0     0     1     1     1
   M2     1     0     0     0     0
   V2     1     0     0     0     0


Move Row D2 to the top and push row V1 down
  Observe Elements of Column 104

         104   102   101   103   105
   D2    1     1     0     0     0
   V1    0     1     1     1     1
   M1    0     0     1     1     1
   D1    0     0     1     1     1
   M2    1     0     0     0     0
   V2    1     0     0     0     0


Move Rows M2 & V2 upwards and push row V1 down
     104   102   101   103   105
D2   1     1     0     0     0
M2   1     0     0     0     0
V2   1     0     0     0     0
V1   0     1     1     1     1
M1   0     0     1     1     1
D1   0     0     1     1     1
Step #5.   If current matrix is the same as the previous, stop; else
           to go 3.
Identify Cells or potential Cells



               104   102   101     103    105
       D2      1     1     0       0      0
       M2
                                                  Cell #1
               1     0     0       0      0
       V2      1     0     0       0      0
       V1      0     1     1       1      1
       M1      0     0     1       1      1       Cell #2
       D1      0     0     1       1      1



   Part Family #1                Part Family #2
       Production Flow Analysis
               -SCOPE-
We learned two (and probably the most
 common) methods/algorithms for
 performing a Production Flow Analysis.

There are a host of other algorithms and
 methods which are used in Academics and
 in the Industry.
                                       (contd..)
       Production Flow Analysis
        -Organizational View-
Production Flow Analysis consists of 5 different
    analyses:

1. Company Flow Analysis
2. Factory Flow Analysis
3. Group Analysis
4. Line Analysis
5. Tooling Analysis
        Company Flow Analysis
• A Planning technique used for the division of large
  companies into factory components. It aims to simplify the
  flow of materials between factories.

• Uses FROM-TO charts and frequency charts and a flow
  analysis (similar to the one discussed in slides 29 – 41).

• Is not a decision making model, but presents data in a way
  that decisions can be made based on a company‟s goal.
  CFA (Analysis)              Company’s
                              Goals




We get a SCHEME for the division of products and
components, machines and facilities into factory sets
       Factory Flow Analysis
An attempt is made at this stage to find major groups
  of departments, and major families of components
  which can be completely processed in these
  departments.
The Goal is to change factories from process
  organization to product organization and to
  minimize interdepartmental material flow


                        (Contd.. FFA Methodology )
           Factory Flow Analysis
              -Methodology-
• Study and map the existing flow system
• Identify the dominant material flows between shops
  (or buildings)
• Determine the Process Route Number (PRN) for each
  part
• Analyze the part by PRN.
• Combine closely associated processes at departments
  that complete most of the parts they make
• If parts are observed to backtrack then such flows are
  eliminated by minor redeployment of equipment
Factory Flow Analysis
    -An Example-
            Group Analysis
The flows in each of the individual shops
 (identified by FFA) are analyzed.
Operation sequences of the parts that are
 being produced in a particular shop are
 analyzed to identify manufacturing cells.
Loads are calculated for each part family to
 obtain the equipment requirements for each
 cell
            Group Analysis
Essentially, while forming and rearranging the
  PFA matrix (slides 29-41) we were
  performing Group Analysis.
Those same algorithms are also employed in
  PFA activities other than Group Analysis
  (namely CFA, FFA etc..)
Choice of algorithm or technique that is best
  suited is, for the most part, a problem
  specific issue
             Line Analysis
A linear or U-layout is designed for the
 machines assigned to each cell.
The routings for each part assigned to the cell
 and the frequency of use of each routing are
 used to develop a cell for:
  – Efficient transport, &
  – Minimum material handling and travel by
    operators.
Line Analysis Example
             Tooling Analysis
A Tooling Analysis helps to schedule the cell by
  identifying families of parts with similar operation
  sequences, tooling and setups.

It seeks to sequence parts on each machine to
   sequence all the machines in the cell to reduce
   setup times and batch sizes.

This increases available machine capacity on
  bottleneck work canters in the cell.
         PFA: Assumptions

• Each component is equally important in
  terms of cost
• Lot size & its associated cost are not
  directly related to grouping procedure
• Routing is assumed to be optimal
          PFA: Weakness

PFA is suitable mostly for small sized
 applications, but it has difficulties
 coping with some large cell formation
 problems when the Machine-Part
 Matrix becomes more complex
 because of problem size
          PFA: Advantages
• Reduces flow distances
• Better suited to JIT and “pull” manufacturing
  as the overall flow is much straighter
• Simple and Easy to implement
• Experience: Lots of Research and Background
  and support software
Questions?!?

Could you use this for a “real-world” problem?
What problems arise from using PFA?