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					Facilities Layout:
Designing Process Layouts

LOVETTE JAM PRADA JACOSALEM

Designing process layouts
The main issue in design of process layouts concerns the relative positioning of the departments involved.

Locations A D B E C F

Work centers to be assigned 1 2 3 4 5 6

Figure 6-8. Work centers must be assigned to locations

PROBLEM: To develop a reasonably good layout, considering that some departments may benefit from adjacent locations whereas others should be separated.

External Factors That Influence Layouts:
• Location of entrance, loading dock, elevators, windows • Areas of reinforced flooring • Noise levels • Safety • Size and locations of restrooms

NOTE:
No algorithms exist to identify the best layout arrangement under all circumstances. Often, planners must rely on heuristic rules to guide trial-and-error efforts for a satisfactory solution to each problem.

Measures of Effectiveness
One advantage of process layouts is their ability to satisfy a variety of processing requirements. Customers or materials in these systems require different operations and different sequences of operations, which causes them to follow different paths in the system. Material-oriented systems – necessitate the use of variable-path material-handling equipment to move materials from work center to work center Customer-oriented systems – people travel must travel or be transported from work center to work center

Major Objective of Process Layout:
▫ To MINIMIZE transportation cost, distance, or time  Usually accomplished by locating departments with relatively high interdepartmental work flow as close as possible.

Other Concerns (in choosing layouts):
• • • • Initial costs in setting up the layout Expected operating costs Amount of effective capacity created Ease of modifying the system

For Improvement of an Existing Layout: • Cost of relocating any work center vs. potential benefits of the move.

Information requirements
 List of departments  Projection of work flows  Distance between locations and the cost per unit of distance to move loads between location  Amount of money to be invested  List of special considerations

Minimizing transportation costs or distances
The most common goals in designing process layouts are minimization of transportation costs or distances traveled.

From-To Charts
LOCATION DEPARTMENT

From A B C

To -

A

B 20 30

C 40 30 -

From 1 2 3

To -

A

B 10 70

C 80 30 -

20 40

20 90

Distance between locations (meters)

Interdepartmental work flow (loads per day)

Sample Problem:
• Using the data from the previous slide, assign the three departments to locations A, B, and C, in such a way that transportation cost is minimized. The cost per meter to move any load is $1.

Step 1:
• List the departments or work centers to be arranged.
Locations Work centers to be assigned

A

B

C

1 2 3

Step 2:
• Rank departments according to highest work flow and locations according to lowest interlocational distances Trip A-B Distance (meters) 20 Department Pair 3-1 Work Flow 90

B-A B-C C-B A-C C-A

20 30 30 40 40

1-3 3-2 2-3 2-1 1-2

80 70 30 20 10

170

100

30

Step 3: Analysis
• 1 and 3 have the highest interdepartmental work flow • Locations A and B are the closest
▫ 1 and 3 assigned to locations A and B
 Not yet certain which department should be assigned to which location

• 2 and 3 have the higher work flow than 1 and 2
▫ 2 and 3 should be located more closely than 1 and 2. ▫ 3 should be between 1 and 2

30

1

170

3

10 0

2

A

B

C

Step 4
• Compute the total daily transportation cost
Dept No. of Loads to: Location Distance to: Loads x Distance

1 2

2: 10 3: 80 1: 20 3: 30

A C

C: 40 B: 20 A: 40 B: 30

10 x 40 = 400 80 x 20 = 1600 20 x 40 = 800 30 x 30 = 900

3

1: 90 2: 70

B

A: 20 C: 30

90 x 20 = 1800 70 x 30 = 2100 7,600

Closeness ratings
Richard Muther developed a more general

approach, which allows for subjective input from analysts or managers to indicate the relative importance of each combination of department pairs.

Code

Department 1
Department 2 Department 3 Department 4 Department 5 Department 6

Degree of Importance Absolutely necessary Very important Important Ordinary importance Unimportant Undesirable

A E X

A U A A

X I

U A

O

O
A

X

A E I O U X

A Muther Grid

In practice, the letters on the grid are often accompanied by numbers that indicate the reason for each assignment:
1. 2. 3. 4. 5. 6. Use the same equipment or facilities. Share the same personnel or records. Sequence of work flow. Ease of communication. Unsafe or unpleasant conditions. Similar work performed.

Sample Problem:
• Assign the six departments from the figure below to a 2 x 3 set of locations using the heuristic rule. Assign the critical departments first.
Department 1 Department 2 Department 3 Department 4 Department 5 Department 6

A
E X

A U A A

X I

U A

O

O
A

X

Step 1:
• Determine critical pairs of departments (those with A or X ratings).
A’s 1-2 1-3 X’s 1-4 3-6

2-6 3-5 4-6 5-6

3-4

Step 2:
• Form a cluster of A links, beginning with the department that appears most frequently in the A list. A’s 1-2

2 6

4

5

1-3 2-6 3-5 4-6 5-6

Step 3:
• Take the remaining A’s in order, and add them to this main cluster where possible. Form separate clusters for departments that do not link with the main cluster. A’s 1-2 1-3

2 1 6

4

3

5

2-6 3-5 4-6 5-6

Step 4:
• Graphically portray the X’s.

1 4 3 6

X’s
1-4 3-6 3-4

Step 5:
• Verify that A’s satisfy the X’s.

1 2 1 6

4
4 5 3 6

3

Step 6:
• Fit the cluster into a 2 x 3 arrangement.
2 1 3 6 5 4

1

2

6

3

5

4

Computer analysis
The size and complexity of process layout problems have led to the development of a number of computerized packages. The obvious advantage of computerized analyses of layout problems is the ability to handle large problems and to consider many different layout alternatives.

Thank You! 


				
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