Facility Layout
Part b
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
2
CRAFT Example
Consider 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.
3
CRAFT Example
(a) Initial Layout with Centroids
50’
A
C
30’
B


D


20’
20’
40’
4
CRAFT Example (cont.)
(b) Flow Data
To
From
A
A
B
C
D
---
2
4
4
B
1
---
1
3
C
2
1
---
2
D
4
1
0
--5
CRAFT Example (cont.)
(c) Distance Matrix
To
From
A
A
B
C
D
---
40
25
55
B
40
---
65
25
C
25
65
---
40
D
55
25
40
--6
CRAFT Example (cont.)
(d) Total Cost for CRAFT
To
From
A
A
B
C
D
Total
---
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
7
CRAFT Example (cont.)
• Possible Two-Way Interchanges:
–AB
–AC
–AD
–BD
–CD
8
CRAFT Example (cont.)
(e) If Departments A and B are
interchanged, then the Layout would be:
30’
B
C
50’
A


20’

D

20’
40’
9
CRAFT Example (cont.)
(f) If Departments A and B are
interchanged in the initial Layout, then
the Distance Chart becomes:
To
From
A
A
B
C
D
---
40
65
25
B
40
---
25
55
C
65
25
---
40
D
25
55
40
--10
CRAFT Example (cont.)
(g) If Departments A and B are
interchanged in the initial Layout, then
the Total Cost Chart becomes:
To
From
A
A
B
C
D
Total
---
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
11
CRAFT Example (cont.)
(h) First Improved Layout when
Departments B and D are interchanged.
This Layout gives a Total Cost = $985
A
D


C
B


40’
12
CRAFT Example (cont.)
• Next, possible Two-Way Interchanges:
–AB
–AC
–AD
–BC
–BD (Takes it to the initial layout; can be ignored)
–CD
13
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
A
D
C
14
CRAFT Example (cont.)
• Next, possible Two-Way Interchanges:
–AB (Takes it to the previous layout; can be ignored)
–AC
–AD
–BC
–CD
15
CRAFT Example (cont.)
(j) The Final Improved Layout is
obtained by interchanging departments C
and D.
This Layout gives a Total Cost = $927
B
C



D
A

40’
16
CRAFT Example (cont.)
(k) The CRAFT Disaster.
This Layout gives a Total Cost = $384
B
C
D
A
17
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
18
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
19
Hybrid Layouts
• Cellular layouts
• Flexible Manufacturing Systems
• Mixed Model Assembly Lines
20
Cellular Layouts
1. Identify families of parts with similar flow paths
2. Group machines into cells based on part families
3. Arrange cells so parts movement is minimized
4. Locate large shared machines at point of use
21
Original Process Layout
Assembly
4
6
7
5
8
2
1
A
10
3
B
9
C
12
11
Raw materials
22
Part Routing Matrix
PARTS
A
B
C
D
E
F
G
H
1
x
2
x
3
4
x
x
x
x
x
x x
x
x
x
MACHINES
5 6 7
8
x
x
x
x
x
x
x
x
x
9
10 11 12
x
x
x
x
x
x
x
x
23
Part Routing Matrix
Reordered To Highlight Cells
PARTS
A
D
F
C
G
B
H
E
1
x
x
x
2
x
x
4
x
x
x
8
x
x
x
MACHINES
10 3 6
x
x
x
x
x
x
9
5
11 12
x
x
x
x
7
x
x
x
x
x
x
x
x
24
Cellular Layout Solution
Assembly
8
10
9
12
11
4
Cell1
Cell 2
6
Cell 3
7
2
Raw materials
1
3
A
C
5
B
25
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
26
Disadvantages Of Cellular Layouts
•
•
•
•
Inadequate part families
Poorly balanced cells
Expanded training and scheduling of workers
Increased capital investment
27
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
28
FMS Layouts
29
Open Field FMS Layout
30
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
31