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8/11/2019 10 Movement
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8/24/04
Paul A. Jensen
Operations Research Models and MethodsCopyright 2004 - All rights reserved
Material Movement
The movement of material through theproduction facility is a waste because
material movement does not add valueto the product.
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The amount of movement
depends on: the set of products manufactured,
the sequence of operations (process) identified foreach product,
the assignment of machines to the operations of theprocesses,
and the layout of the machines in the manufacturingfacility.
Here we assume that the first two are fixedand we concentrate on the latter two.
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The several generic types of
layout
M1 M2
M3
M5
M4
M7
M6
Offices
The Job shop
M1
M2
M3
M5
M4
M7
M6
Offices
The assembly line or
flow shop
Offices
M3
M2
M1
M4
M7
M1
M5
M6M2
M7
M2
M3
M4
M6
Group technology
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Example Orders for products arrive as Poisson processes.
Processing begins when an order arrives.
Operations are performed in a numerical sequence. There are no losses in the operations.
Operation Times (hours/unit)
PRODUCTS
Operation A B C D E F G H I J K L
1 Mould 0.1 0.1 0.2 0.2 0.3 0.1 0.4 0.6 0.7 0.4 0.1 0.1
2 De-fraze 0.3 0.5 0.2 0.1 0.23 Barrel Polish 0.3 0.6 0.2 0.2
4 Test 0.4 0.1 0.3
5 Machine 0.4 0.2 0.2 0.3 0.4
6 Paint 0.2 0.2 0.2 0.2 0.2 0.2 0.6
7 Sub-assemble 0.1 0.3 0.2 0.3 0.1 0.1
8 Chemical Test 0.2
9 Dimensional insp. 0.1 0.3 0.1 0.2 0.5 0.4 0.2 0.2
10 Final insp. 0.4 0.4 0.2 0.3 0.3 0.2 0.2 0.4 0.1 0.2 0.3 0.3
Weekly Demand 100 200 50 300 80 40 120 200 250 100 120 180
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Machine information Each operation requires a unique machine.
All machines operate 40 hours per week.
Assume operation times have an exponentialprobability distribution.
Provide enough machines so that all
workstations are to have no more than 80%utilization.
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Space and Economic
Information
WIP requires 0.4 sq. m. floor space per unit.
Provide sufficient space at each station toaccommodate WIP 90% of the time.
Transportation cost is $0.10/unit-meter Use a plant with length twice as great as width.
The cost of the plant is $20 per week per squaremeter.
Operation 1 2 3 4 5 6 7 8 9 10
Machine Size (sq.m.) 2 3 4 5 4 3 2 3 4 1
Machine cost ($/w eek) 50 30 40 30 100 80 60 20 70 40
Value Added ($) 10 1 2 1 3 1 2 2 1 1
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Design a plant that uses a job
shop (or functional) layout
M1 M2
M3
M5
M4
M7
M6
Offices
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Step 1: Queuing Analysis Do a Queuing Analysis for each
machine type
Machine 1 2 3 4 5 6 7 8 9 10
Arrival Rate
Service Rate
Number of Mach.Spaces for WIP
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Queuing Analysis
Machine 1 2 3 4 5 6 7 8 9 10
Arrival Rate 1740 850 520 440 540 1270 760 200 1120 1740Service Rate 129 158 125 114 129 156 197 200 187 142
Number of Mach. 17 7 6 5 6 11 5 2 8 16
Spaces for WIP 4 5 3 6 3 3 6 1 4 3
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Step 2: Space Analysis Find the space requirements of each
machine type.
Find the space required for WIP.
Machine 1 2 3 4 5 6 7 8 9 10
Number
Space
Space for WIP
Total Space
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Space analysis
Machine 1 2 3 4 5 6 7 8 9 10
Number 17 7 6 5 6 11 5 2 8 16
Space for Mach. 34 21 24 25 24 33 10 6 32 16
Space for WIP 2 2 2 3 2 2 3 1 2 2
Total Space 36 23 26 28 26 35 13 7 34 18
Space for Plant 246 Sq. M.
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Step 3: Flow Analysis Construct the from-to chart for weekly
flowsMachine 1 2 3 4 5 6 7 8 9 10
1
2
3
4
56
7
8
9
10
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Step 4: Construct a Layout Use a plant dimension of 12x24 with
area 288 sq. m.1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
1
2
3
4
5
6
78
9
10
11
12
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Step 5: Economic Analysis Plant cost:
Machine cost:
Transportation Cost Cost of WIP
Total Cost:
How will these costs change with larger
lot sizes?
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Design a plant that uses a
flow shop layout We assume that each product visits each station but
receives no processing at some stations.
What do you think changes with respect to thefunctional layout?
M1
M2
M3
M5
M4
M7
M6
Offices
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Queuing and space analyses
Machine 1 2 3 4 5 6 7 8 9 10
Arrival Rate
Service Rate
Number of Mach.
Spaces for WIP
Machine 1 2 3 4 5 6 7 8 9 10
Number
Space
Space for WIP
Total Space
Queuing analysis
Space analysis
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Flow Analysis Construct the from-to chart for weekly
flowsMachine 1 2 3 4 5 6 7 8 9 10
1
2
3
4
5
6
7
8
9
10
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Economic analysis Plant cost:
Machine cost:
Cost of WIP at machines:
Cost of WIP in material movement:
Total Cost:
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Design a plant that uses a
separate line for each product Let moulding and final inspection be
separate departments
What will be different in this type oflayout?
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Queuing and space analyses
for each productProduct A
Machine 1 2 3 4 5 6 7 8 9 10
Arrival Rate
Service Rate
Number of Mach.
Spaces for WIP
Total Space
Product B
Machine 1 2 3 4 5 6 7 8 9 10Arrival Rate
Service Rate
Number of Mach.
Spaces for WIP
Total Space
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Economic Analysis Plant cost:
Cost of WIP at machines:
Cost of WIP in material movement:
Total Cost:
How does this cost relate to the cost ofa functional layout?
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Design a plant that uses group
technology Let moulding and final inspection be separate departments
Offices
M3M2
M1
M4
M7M1
M5
M6M2
M7
M2
M3
M4
M6
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Queuing
and spaceanalysis foreach family
Family 1
Machine 1-2 1-6 1-8 1-9
Arrival Rate
Service Rate
Number of Mach.
Spaces for WIPTotal Space
Family 2
Machine 2-5 2-6 2-7
Arrival Rate
Service RateNumber of Mach.
Spaces for WIP
Total Space
Family 3
Machine 3-3 3-4 3-5 3-6 3-7 3-9
Arrival Rate
Service Rate
Number of Mach.
Spaces for WIP
Total Space
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Flow AnalysisMachine 1 1-2 1-6 1-8 1-9 2-5 2-6 2-7 3-3 3-4 3-5 3-6 3-7 3-9 10
1
1-2
1-6
1-8
1-9
2-5
2-6
2-7
3-33-4
3-5
3-6
3-7
3-9
10
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Economic Analysis Plant cost:
Cost of WIP at machines:
Cost of WIP in material movement:
Total Cost: