Facility Layout

Part b

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Computerized Layout Solutions

• Classification A–Construction Algorithm

• CORELAP, ALDEP, PLANET

–Improvement Algorithm• CRAFT

• Classification B–Relationship Diagramming Based

• CORELAP, ALDEP

–From-To Chart (Block Diagramming) Based• PLANET, CRAFT

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CRAFT ExampleConsider a facility with four departments A, B, C, and D. The initial layout and dimensions of each department area are given in the diagram (a). The distance and flow information for this initial layout are given in matrices (b) and (c). Develop an improved layout using the two-way exchange procedure.

Please Note in CRAFT:• Distances are measured from the centroid of the area.• Two-Way Interchanges imply that departments with common boundaries and/or same areas can be switched.

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CRAFT Example(a) Initial Layout with Centroids 50’ 30’ 20’ 20’ 40’

A

C

B

D

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CRAFT Example (cont.)(b) Flow Data To

From A B C D

A --- 2 4 4

B 1 --- 1 3

C 2 1 --- 2

D 4 1 0 ---

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CRAFT Example (cont.)

(c) Distance Matrix

To From

A B C D

A --- 40 25 55

B 40 --- 65 25

C 25 65 --- 40

D 55 25 40 ---

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CRAFT Example (cont.)

(d) Total Cost for CRAFT

To From

A B C D Total

A --- 80 100 220 400

B 40 --- 65 75 180

C 50 65 --- 80 195

D 220 25 0 --- 245

Total

310 170 165 375 $1,020

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CRAFT Example (cont.)

• Possible Two-Way Interchanges:–AB–AC–AD–BD–CD

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CRAFT Example (cont.)(e) If Departments A and B are interchanged, then the Layout would be: 30’ 50’ 20’ 20’ 40’

A

C

B

D

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CRAFT Example (cont.)

(f) If Departments A and B are interchanged in the initial Layout, then the Distance Chart becomes: To

From A B C D

A --- 40 65 25

B 40 --- 25 55

C 65 25 --- 40

D 25 55 40 ---

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CRAFT Example (cont.)(g) If Departments A and B are interchanged in the initial Layout, then the Total Cost Chart becomes:

To From

A B C D Total

A --- 80 260 100 440

B 40 --- 25 165 230

C 130 25 --- 80 235

D 100 55 0 --- 155

Total

270 160 285 345 $1,060

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CRAFT Example (cont.)(h) First Improved Layout when Departments B and D are interchanged.

This Layout gives a Total Cost = $985 40’

A

C

B

D

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CRAFT Example (cont.)

• Next, possible Two-Way Interchanges:–AB–AC–AD–BC–BD (Takes it to the initial layout; can be ignored)–CD

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CRAFT Example (cont.)(i) The next improved Layout Design can be obtained from CRAFT by interchanging departments A and B: This Layout gives a Total Cost = $969

B

C

A

D

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CRAFT Example (cont.)

• Next, possible Two-Way Interchanges:–AB (Takes it to the previous layout; can be ignored)–AC–AD–BC–CD

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CRAFT Example (cont.)(j) The Final Improved Layout is obtained by interchanging departments C and D.

This Layout gives a Total Cost = $927 40’

D

B

C

A

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CRAFT Example (cont.)(k) The CRAFT Disaster.

This Layout gives a Total Cost = $384

B

C

A

D

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Service Layouts

• Usually process layouts due to customers needs• Minimize flow of customers or paperwork• Retailing tries to maximize customer exposure to

products• Computer programs consider shelf space, demand,

profitability• Layouts must be aesthetically pleasing

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Designing Product Layouts

• Product layouts or assembly lines• Develop precedence diagram of tasks• Jobs divided into work elements• Assign work elements to workstations• Try to balance the amount work of each

workstation

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Hybrid Layouts

• Cellular layouts

• Flexible Manufacturing Systems

• Mixed Model Assembly Lines

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Cellular Layouts

1. Identify families of parts with similar flow paths2. Group machines into cells based on part families3. Arrange cells so parts movement is minimized4. Locate large shared machines at point of use

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Original Process Layout

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1

2

3

4

5

6 7

8

9

10

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A B C Raw materials

Assembly

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Part Routing Matrix

MACHINESPARTS 1 2 3 4 5 6 7 8 9 10 11 12 A x x x x x B x x x C x x x D x x x x x E x x x F x x x G x x x x H x x x

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Part Routing MatrixReordered To Highlight Cells

MACHINESPARTS 1 2 4 8 10 3 6 9 5 7 11 12 A x x x x x D x x x x x F x x x C x x x G x x x x B x x x H x x x E x x x

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Cellular Layout Solution

12

12 3

4

5

6

7

8 910

11

A BCRaw materials

Cell1 Cell 2 Cell 3

Assembly

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Advantages Of Cellular Layouts

• Reduced material handling and transit time• Reduced setup time• Reduced work-in-process inventory• Better use of human resources• Easier to control• Easier to automate

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Disadvantages Of Cellular Layouts

• Inadequate part families• Poorly balanced cells• Expanded training and scheduling of workers• Increased capital investment

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Flexible Manufacturing Systems

• Automated machining operations• Automated material handling• Automated tool changers• Computer controlled system• Designed around size of parts processed &

average processing time for parts• Can process wide variety of items quickly

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FMS Layouts

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Open Field FMS Layout

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Mixed Model Assembly Lines

• Produce multiple models in any order on one assembly line

• Issues in mixed model lines–line balancing–U-shaped line–flexible workforce–model sequencing