Plant Layout
A Systematic Layout Planning
(SLP) Approach
Mohamed Iqbal Pallipurath
1
THE NEED FOR
GOOD FACILITIES PLANNING
1. Plant facilities influence operating costs and
profits.
2. Planning allows facilities and its operations
(OSHA, ISO 14001, etc.) to comply with laws
and/or regulations.
3. Facilities are fixed investments involving high
capital-cost expenditures.
4. Facilities are inflexible and long term
commitments.
5. The planning, design and construction of facilities
require long lead times.
6. Good planning helps to avoid disruptions in
production and shipping or delivery.
2
THE NEED FOR
GOOD FACILITIES PLANNING
7. The quality of facilities influences the attitudes of
and the ability to attract suitable employees.
8. Industrial facilities must be planned to meet
anticipated future requirements yet compete
profitably today.
9. Facilities need to be planned for an appropriate
degree of flexibility, expandability, versatility…
10. Good plans help management to take advantage
of business opportunities that arise.
11. Good planning is an aid to obtain approval and
financing monies.
12. Good planning reduces the high materials handling
3
$ resulting from “ad hoc” expansion of plant
Economic Investment/Consequence ($)
ECONOMIC IMPACT OF FACILITIES PLANNING
Resources invested to
provide the facilities
Plan
20:1
Consequence on operations
of facilities
Design
2:1
Time
Build & Install
1:10
DEFINING PERFORMANCE
OBJECTIVES
1.
2.
3.
5
DEFINING PERFORMANCE
OBJECTIVES
4.
5.
6.
6
TYPES OF MANUFACTURING
LAYOUT CONFIGURATIONS
I. Product Line Layout
Product
A
B
C
7
CHARACTERISTICS
High volume production
 Special purpose machines and
material handling equipment

Throughput rates--high
 Work-in-process--low
 Setup/Run time ratio--low

System is very inflexible
 Control is relatively simple

8
TYPES OF MANUFACTURING LAYOUT CONFIGURATIONS
II. Flow Line Workcell

T
T



T
M
M
T
M
D
D
M
D
SG
CG
CG
D
T = turning
D = drilling
M = milling
CG = center grinding
SG = surface grinding
SG
GOAL:
GAIN the advantages and efficiency of high volume production in a
LOW/MEDIUM VOLUME (FLEXIBLE) ENVIRONMENT.
GT-FLOW LINE WORKCELL
CHARACTERISTICS
Buffer
1
Workstation
1
Buffer
2
Workstation
1
Buffer
m
Workstation
m
10
GT-FLOW LINE WORKCELL
CHARACTERISTICS
1. Processes GT-based families of parts with frequent
job change-over and small to medium batch sizes
2. Piece by piece (continuous flow)
processing/movement
3. No backtracking in sequence flow, but machine
skipping does occur
4. Accommodates flexible-type automation: CNC
machines, robots for part handling
5. Finite buffers (resulting in machine blocking and
starvation
11
TYPES OF MANUFACTURING LAYOUT CONFIGURATIONS
III. Cellular Manufacturing
(GT Workcell)
CHARACTERISTICS
1. Dissimilar processes/machines
2. Similar parts (families) run in small to
medium batch sizes
3. Mini - job shops
13
Process(Functional) Layout
“Shaft”
Sawing
Turning
S S S
T T T
S S S
T T T
Grinding
T T T
G G G
G G G
Heat Treating
HT
Gear Cut
HT
H
T
Milling
M
M
M
Boring
GC
GC
B B
GC
GC
B B
Characteristics
of Process Layouts


Low Volume, High Variety Production with Random
Routing (Spaghetti-Like Flow)
General Purpose Machines-






Machine setups are frequent and long
Work-In-Process -- High
Throughput Rates tend to be Low
Material Handling -- High
Operator Utilization -- Low?
Throughput Times (Lead Time) -- High
System is Very Flexible, produces many different
types of parts: gears, shafts, pinions, housings,
clamps, etc.
15
THE P-Q CURVE
(High)
Product A
Product B
Product C
(Q) Volume or Quantity
Q
Etc.
P
(Low)
(Low)
(High)
(P) Variety
(High)
Product
Line
G.T.
Flowline
Workcell
Part
Volume
G.T.
Manufacturing
Workcell
Functional
(Job-Shop)
(Low)
(Low)
Part Variety
(High)
Part Volume/Variety Relationships with
Manufacturing Systems Configurations
MATERIAL FLOW
Importance of Material Flow
Properly Planned Material Flow
Effective Arrangement of Facilities
Efficient Operations
Profitability/Viability
18
Efficient Operations Involve:
1.
2.
3.
4.
5.
6.
7.
Good utilization of floor space
Reduced materials handling
Appropriate equipment utilization
Safety
Less congestion
Less wasted time/efforts
Flexibility
19
MATERIAL FLOW
KEY QUESTIONS
1. What is the most effective sequence of moving
materials?
Eliminate?
Combine?
Improve?
Change Order?
2. What is the intensity and direction?
Need to visualize the flow
20
FLOW OF MATERIAL vs P-Q MIX
LAYOUT TYPE
I
I
II
III
IV
II
Product Line
Flow Line Workcell
G.T. Workcell
Functional
III
IV
21
TYPE I
Casting
Sheet Steel
4 Tons
0-4
Turn
3.3 Tons
0-5
10 Tons
Drill
3 Tons
Storage
0-1
Blank
9 Tons
Turnings
0.7 Tons
0-2
Offal
1 Ton
Form
9 Tons
Turnings
0.3 Tons
0-3
Trim
7 Tons
Bolts
10.5 Tons
0-6
Scrap
2 Tons
Assemble/
Inspect
Operation Process Chart showing intensity of material flow and the out-flow of chips and
scrap. (Muther, SLP)
TYPE II
Operation
Part or Product A
B
C
Saw
1
1
1
Center
2
2
2
Turn
3
3
Heat Treat
4
Grind
5
Mill
D
1
4 *
2
3
4
5
3
5
4
Multi-Product Process Chart
*Shows problem flow to be resolved by design engineering and manufacturing
engineering
TYPE III
Parts
Machines
5
8
7
12 13
1
10
2
11
14
3
15
4
9
6
4
1
6
Exceptions
8
3
9
2
14
12
5
7
13
11
10
Part-Machine Matrix of
Production Flow Analysis
Turn
1
Hob
2
Slot
Broach
Heat Treat
Drill
Inspect
Wash
Mill
Store
FROM
Hob
TO
Turn
TYPE IV
1
2
3
4
5
6
7
8
9
10
=
3
26
-
=
3
6
1
5
1
160 232
2
631 684
7
5
262
576
Slot
3
-
-
=
Broach
4
-
-
-
Heat Treat
5
-
1
2
1
20
-
-
-
-
-
-
-
-
-
-
-
10
-
-
=
-
-
-
-
5
576
=
3
910
-
-
-
-
=-
9
752
-
-
Inspect
7
-
-
-
-
-
-
-
-
1
8
1
12
22
-
1
1
7
414
-
5
-
-
6
8
-
-
-
Drill
Wash
-
-
12
3
12
-
-
Mill
9
-
-
-
-
-
-
-
-
=
-
Store
10
-
-
-
-
-
-
-
-
-
=
TOTALS
FROM-TO CHART
Number of Parts
x
y
Number of Pieces
TOTALS
Activity
Pair
(Route)
8-13
1-3
3-4
8-15
3-12
11-15
10-13
3-7
7-15
1-14
4-12
4-9
4-15
1-7
2-3
11-15
3-5
1-4
1-12
2-8
11-9
Seq.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
500
1000
1500
2000
2500
3000
3500
4000 4500
FLOW - OF - MATERIAL INTENSITY
RANK THE FLOWS
A
E
A:
E:
I:
O:
U:
KEY
Absolutely Necessary
Especially Important
Important
Ordinary
Unimportant
I
O
U
NON-FLOW (CLOSENESS)
RELATIONSHIPS
Flow based on routings is not the sole
basis for layout arrangements.
Adapted from Muther
27
NON-FLOW (CLOSENESS)
RELATIONSHIPS
Other Factors
 Supporting Services
Tool Room (not routed)
 Rest Areas
 Central Coolant Tanks
 Shop Superintendent’s Office

Adapted from Muther
28
NON-FLOW (CLOSENESS)
RELATIONSHIPS
Other Factors
 Separation of Areas

Welding away from assembly
Dirty
Dangerous

Separate
Delicate
High Pop
Outside Doors / Separate / N/C
Adapted from Muther
29
NON-FLOW (CLOSENESS)
RELATIONSHIPS
In some cases, flow is simply not
important
No Significant Flow
 Service, Repair, Tool Room
 Jewelry (one load per week)
Adapted from Muther
30
1
2
3
4
5
6
Punch Press
Auxiliary
Punch Press
Drilling
Grinding
General
Fabrication
1
I
1
D
2
I
2
U
U
Wet Tumble
2
U
U
U
8
9
10
Special
Production
Raw Material
Storage
In-Process
Storage
I
2
E
2
Shop Toilet
12
Shop Office and
Tool Room
I
2
I
2
U
U
Assembly
11
U
U
U
U
I
2
U
I
2
O
2
U
E
2
U
6
U
7
8
I
2
A
2
O
O
2
A
2
I
3
2
O
2
O
3
U
U
U
U
U
O
3
O
4
5
U
U
E
2
U
4
U
U
7
RELATIONSHIP CHART
3
O
2
O
2
U
E
O
3
U
5
I
4
E
2
O
3
O
4
9
I 10
2 O 11
U 3
I 12
13
O 4
14
O 4
15
4
X
6
U
This block shows relation
between “1” and “3”
1
U
2
3
13
14
15
Importance of Relationship (top)
Adapted from Muther
Reasons in Code (bottom)
RELATIONSHIP CHART Codes
Code
“Closeness”
Rating
CLOSENESS
Value
A
Absolutely Necessary
4
E
Especially Important
3
I
Important
2
O
Ordinary Closeness OK
1
U
Unimportant
0
X
Undesirable
-1
32
RELATIONSHIP CHART
Value
Reasons behind
the “Closeness”
Value
1
Equip. used by same persons
2
Movement of material
3
Movement of personnel
4
Supervision and/or support
5
Require same utilities
6
Noise and dirt
7
8
9
Adapted from Muther
REASON
RELATIONSHIP DIAGRAMS
Conventions for diagramming activity relationships
Vowel Letter
No. Value
No. of Lines
Closeness Rating
Color Code
A
4
Absolutely Necessary
Red**
E
3
Especially Important
Orange Yellow**
I
2
Important
Green**
O
1
Ordinary
Blue**
U
0
Unimportant
Uncolored**
X
-1
Not Desirable
Brown**
XX
-2, -3, -4, ?
Extremely Undesirable
Black
PROCEDURE/EXERCISE
Dept. No.
Sq. Feet
Dept. Desc.
1
5,000
Parts Storage
2
10,000
Ship/Receiving
3
2,500
Welding
4
2,500
Testing
5
7,500
Machining
6
5,000
Assembly
7
2,500
Paint
E
U
O
U
U
X
I
I
I
U
E
I
X
A
O
U
U
X
I
U
A
Figure 1: Relationship Chart
35
PROCEDURE/EXERCISE
TO
FROM
1
2
3
4
5
1
2
50
170
40
80
4
50
6
7
7
170
3
5
6
50
20
20
120
20
120
120
Figure 2: From-To Chart (in Loads per Weeks)
36
1
Determine Total Flow
TO
FROM
1
1
2
3
4
5
2
3
4
5
50
6
7
170
170
90
80
120
50
20
140
120
20
6
7
37
2
Rank the Flows
200
180
140
120
100
80
60
3-7
3-6
1-2
3-5
2-5
4-7
2-7
4-6
2-3
20
5-7
40
1-6
Total Flow
160
0
0
1
2
3
4
5
6
7
8
9
10
11
38
3
Combine Flow & Non-Flow Relationships
Activity Pairs
1-2
1-3
1-4
1-5
1-6
1-7
2-3
2-4
2-5
2-6
2-7
3-4
3-5
3-6
3-7
4-5
4-6
4-7
5-6
5-7
6-7
Non Flow: Flow
1 to 1 Ratio
3
0
0
2
3
0
1
0
2
2
0
-2
0
-2
-2
0
4
2
1
0
4
1
0
0
0
4
0
4
0
1
0
3
0
2
1
0
0
3
3
0
0
0
Combined Total Points
4
0
0
2
7
0
5
0
4
2
3
-2
2
-1
-2
0
7
5
1
0
4
39
4
Rank the Combined Points
10
9
7
6
5
4
3
5-6
2-6
1-5
2-7
6-7
2-5
1-2
4-7
2-3
4-6
1
3-5
2
1-6
0
0
1
2
3
4
5
6
7
8
9
10
11
12
3-6
3-4
3-7
Total Points
8
Activity Pairs
40
5
Develop Combined Relationship Chart
(Flow and Non-Flow)
1
5,000
Parts Storage
2
10,000
Ship/Receiving
3
2,500
Welding
4
2,500
Testing
5
7,500
Machining
6
5,000
Assembly
7
2,500
Paint
I
E
O
XX
I
O
A
O
X
A
I
XX
E
I
41
6
Develop Relationship Diagram
i
Place “A” Relationship Values on Grid
ii
Add the “E” Relationship Values and Adjust
Diagram to Minimize Distance X Flow Value
iii
Place “A” Relationship Values on Grid
42
6. Relationship Diagram
A
E
I
O
U
X
XX
+
+
+
+
+
+
+
+
+
+
+
+4
+6
+1
+
+
+7
+2
+3
+
+
+
+5
+
+
7. Measures of Effectiveness
Min Z = S S L
ij
i j
Dij
L ij = Load between departments i & j, often measured
by the value of the Vowel Letter.
A = 4, E = 3, I = 2, O = 1, U = 0, X = -1
Dij = Distance between departments i & j (move only
at Right angles)
*Many Variations of this Concept
8.
Space Relationship Diagrams
9.
Layouts
7. Diagram Score:
Department Pair
Lij
Dij
Zij
1-2
1-3
1-4
1-5
1-6
1-7
2-3
2-4
2-5
2-6
2-7
3-4
3-5
3-6
3-7
4-5
4-6
4-7
5-6
5-7
6-7
2
0
0
1
4
0
3
0
2
1
2
-1
1
-1
-1
0
4
3
0
0
0
2
0
2
3
1
3
1
2
1
1
1
3
2
2
2
3
1
1
2
2
2
4
0
0
3
4
0
3
0
2
1
2
-3
2
-2
-2
0
4
3
0
0
0
21
45
Types of Layouts
(Q)
Number of
pieces/part#
Product
CM
Job-Shop
(process)
Number of Part Numbers
(P)
46
PRODUCT LAYOUT
Product Layout: Continuous Flow Production System
Definition: Layout is dictated by the product. (P)
Suited to manufacturing processes with single output
Equipment arrangement  operation sequence
High production (volume) items and stable demand,
similar products:
47
PRODUCT LAYOUT

Materials move by units in a product line, not by
lots.
*?
UNIT
1.
2.
3.
demand
Operations performed at various workstations
*The Output is determined by the slowest operation
*
\
TASK is to BALANCE the workstations in terms
of the work done (time) and satisfy the required
output.
48
PRODUCT LAYOUT
Two Types of
Problems:
Fabrication Lines
Required Information:
(R)
Sequence of operations or job
elements
(T)
Time required for each
operation or independent
element
Assembly Lines
Output required
(Q)
49
EXAMPLE
Design a fabrication line to manufacturing a
product with the following 7 operations.
Initially assume:
No scrap losses
100% eff. & 480 min/day
1000 units required per day
50
EXAMPLE
Specifically determine
A) The number of machines required at each
workstation, and
B) The % of idle time for the following operations:
Opn #
Operation
1
2
3
4
5
6
7
Saw
Center
Turn (RGH)
Heat Treat
Fin Turn
Grind
Mill
51
OUTPUT REQ’D: 1000 UNITS/DAY
Opn
A
Std Time
B
Cont. Output
C
D=A*B*C
Machines Theoretical
Req’d
Prod. Time
1
2
3
4
5
6
7
Totals
1.20 min
0.80 min
1.00 min
2.40 min
0.40 min
3.00 min
1.20 min
10.0 min
400 pcs
600 pcs
480 pcs
200 pcs
1200 pcs
160 pcs
400 pcs
per machine
3
2
3
5
1
7
3
Idle =
11520-10000
11520
1440 min
960 min
1440 min
2400 min
480 min
3360 min
1440 min
11,520 min
Std Time
(Output)
Actual Prod.
Time
1200 min
800 min
1000 min
2400 min
400 min
3000 min
1200 min
10,000 min
13.2%
52
OUTPUT REQ’D: 1200 UNITS/DAY
Opn
Number of
Stations
Theo. Time
1
2
3
4
5
6
7
3
2
3
6 (+1)
1
8 (+1)
3
1440
960
1440
2880
480
3840
1440
12,480
Idle =
12480-12000
12480
Act. Time
=
=
>
=
=
>
=
1440
960
1200
2880
480
3600
1440
12,000
3.8%
53
OUTPUT REQ’D: 800 UNITS/DAY
Opn
Number of
Stations
Theo. Time
1
2
3
4
5
6
7
2 (-1)
2
2 (-1)
4 (-1)
1
5 (-2)
2 (-1)
960
960
960
1920
480
2400
960
8640
Idle =
640
8640
Act. Time
=
=
=
=
>
=
=
960
640
800
1920
320
2400
960
8000
7.4%
54
SUMMARY
Output
Rate
Total Number
Of Machines
%
Idle
800
900
1000
1100
1200
1300
1400
1500
18
22
24
7.4
14.7
13.2
26
3.8
CONCLUSIONS:
55
INVENTORIES
Now how does one handle the idle time which occurs?
*i.e., complete balance not possible.
Ans.
Work in-process inventories are used to “decouple” operations.
Slack for machine breakdowns
Stat
1
Inven Stat
2
Inven Stat
3
56
SYSTEM UTILIZATION LEVELS
Production Level (pcs/hr)
Stat No.
Hourly Capacity
per “Machine”
40
55
60
2)
1
55
73%
100%
2)
2
3
4
40
85
105
100%
47%
38%
2)
55%
2)
69%
65%
52%
80
73%
2)
75%
71%
57%
1005
94%
76%
2)
5
60
Avg. Util.
Add’l Mach.
New Util.
67%
65%
2
54%
92%
75%
1
64%
100%
70%
5
61%
67%
81%
2
72%
57
How to Handle Scrap
Station 1
Station 2
Station 3
?
150 pcs/hr


Operation
Std. Time
(min/part)
Scrap%
Efficiency%
1
0.3
5
0.9
2
0.5
3
1.05
3
1.1
4
1.00
What inputs are required at each station?
How many machines are required at each station?
58
TERMS
Inputn =
Outputn
(1.00-Scrapn)
Efficiency =
Std. Time
Actual Time
X 100%
59
Station #3
Input
Input =
150
150
(1-.04)
= 156.25 = 157
Std Time = 1.1 min/pc.
54.5 pcs/std. hr.
x 1.00 Eff.
54.5
54 pc/hr./machine
2.91
157/54
3 machines
60
Station #2
2
Input =
157
=
Std Time = .5 min/pc.
120 pcs/std. hr.
x 1.05 Eff.
126 pcs/hr./machine
162/126 = 1.28
2
61
Station #1
Input =
=
Std Time = .3 min/pc.
200 pcs/std. hr.
x .90 Eff.
180 pcs/hr./machine
171/180 = .95
1
62
Operation
Production
time (min)
per Mc
Mc
Theoretical
time (min)
Idle time
(min)
1
Actual
production
rate
(part/hr) per
Mc
180
57
1
60
3
2
126
77.14
2
120
42.86
3
54
174.44
3
180
5.56
360
51.42
Total
308.58
Idle = (360 - 308.58)/360 = 0.143
Utilization = 1 - 0.143 = 0.857
63
Final Layout
3
2
1
162
157
171
150
64
Class
Problem
A circuit line consists of four processes:
A: chip production,
B: assembly,
C: test, and
D: package.
Three chips go into every assembly.
The production and scrap rates are as follows:
Process
Production Rate
(Pcs/hr)
A
B
C
D
200
60
55
70
Scrap (%)
15
10
5
0
What is the output rate of this line?
65