Facility Layout
Dr. Everette S. Gardner, Jr.
Machine shop process layout
Receiving
Grinders
Mills
Raw
Large number
of
low volume
products
matl.
storage
Assembly
Drills
Planers
Lathes
Automatics
Part A
Part B
Inspection
Finished
goods
storage
Facility Layout
2
Product layout
Receiving
Raw matl.
storage
Fabrication
line-part A
Finished
goods
storage
Fabrication
line-part B
Planer
Lathe
Drill
Mill
Mill
Drill
Small number
of
high volume
products
Grinder
Mill
Assembly line
Automatic
Facility Layout
3
Possible solutions to the process
layout problem
6 Department problem has 6! or 720 possible solutions:
A
B
C
D
E
F
I.E., there are 720 different arrangements of the 6 departments
on the 6 locations on the grid.
Facility Layout
4
Possible solutions to the process
layout problem (cont.)
Problem complexity grows exponentially:
Nbr. depts.
10
15
20
50
Solutions
3,628,800
1.31 x 10^12
2.43 x 10^18
3.04 x 10^64
Facility Layout
5
Solutions considered by Craft
• N! solutions to problem with N depts.
• Craft considers only
N(N-1)
2
pairs of exchanges,
starting with each
dept.
Facility Layout
6
Craft initial layout of furniture plant
A
B
C
D
E
F
G
I
H
J
TOTAL COST = $2524.68
Facility Layout
7
Craft final layout
A E
C
I
G F B H J D
TOTAL COST = $766.68
Facility Layout
8
Synopsis of assembly line balancing
1. Set up a precedence table.
2. Compute required cycle time:
C = (production time) / (required output in units)
3. Compute minimum cycle time:
CMIN = time for longest task
4. Compute minimum number of stations:
SMIN = (sum of all times) / C
Facility Layout
9
Synopsis of assembly line balancing
(cont.)
5.
Select rule by which tasks are assigned to work
stations.
Examples:
(1) select tasks with longest operation times first or
(2) select tasks with largest number of following tasks first
6.
Assign tasks to the first work station until the sum of
the task times are equal to the cycle time, or no other
tasks are feasible. Repeat for stations 2, 3, … until
tasks are assigned.
7.
Evaluate the efficiency of the balance:
E = (sum of all times) / (actual nbr. of stations x C)
Facility Layout
10
Line balancing quiz
0.4
B
1.1
A
0.5
0.3
1.1
E
G
C
1.2
0.4
0.8
D
F
H
0.7
0.3
I
J
Balance this production line to achieve an output of 367 units per
day. Available production time is 8 hrs. less a 40 min. lunch break.
Use the largest number of following tasks rule to select tasks for
work stations. Break ties with the longest operation time.
Facility Layout
11
Multiple solutions in line balancing
6
B
7
3
A
4
F
5
C
H
5
5
D
G
2
E
Facility Layout
12
Multiple solutions in line balancing
(cont.)
Number of solutions
84
25
3
1
2
3
4
5
6
7
Stations
Facility Layout
13
Volvo layouts
Rotating
round table
with definite
cycle time -facilitates teamwork
Facility Layout
14
Volvo layouts (cont.)
Horseshoe
conveyor
sections to
enable worker
communications
Facility Layout
15
Volvo layouts (cont.)
Interim storage
areas to separate
line into definite
supervisory groups
Storage
Supervisor
B
Supervisor
A
Facility Layout
16
Volvo layouts (cont.)
Machines grouped
in banks of 3
so workers can
exchange jobs and
assist each other
in set-up
Facility Layout
17
Volvo continued
E
S
S
E
S
S
E
S
S
Connections of subassembly islands feed parts/components to
end-assembly islands—each island functions as a separate team
Facility Layout
18