8/24/04 Paul A. Jensen Operations Research Models and Methods Copyright All rights reserved Material Movement The movement of material through the production facility is a waste because material movement does not add value to the product.

2 The amount of movement depends on: the set of products manufactured, the sequence of operations (process) identified for each product, the assignment of machines to the operations of the processes, and the layout of the machines in the manufacturing facility. Here we assume that the first two are fixed and we concentrate on the latter two.

3 The several generic types of layout

4 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.

5 Machine information Each operation requires a unique machine. All machines operate 40 hours per week. Assume operation times have an exponential probability distribution. Provide enough machines so that all workstations are to have no more than 80% utilization.

6 Space and Economic Information WIP requires 0.4 sq. m. floor space per unit. Provide sufficient space at each station to accommodate 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 square meter.

7 Design a plant that uses a job shop (or functional) layout

8 Step 1: Queuing Analysis Do a Queuing Analysis for each machine type

9 Queuing Analysis

10 Step 2: Space Analysis Find the space requirements of each machine type. Find the space required for WIP.

11 Space analysis

12 Step 3: Flow Analysis Construct the from-to chart for weekly flows

13 Step 4: Construct a Layout Use a plant dimension of 12x24 with area 288 sq. m.

14 Step 5: Economic Analysis Plant cost: Machine cost: Transportation Cost Cost of WIP Total Cost: How will these costs change with larger lot sizes?

15 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 the functional layout?

16 Queuing and space analyses Queuing analysis Space analysis

17 Flow Analysis Construct the from-to chart for weekly flows

18 Economic analysis Plant cost: Machine cost: Cost of WIP at machines: Cost of WIP in material movement: Total Cost:

19 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 of layout?

20 Queuing and space analyses for each product

21 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 of a functional layout?

22 Design a plant that uses group technology Let moulding and final inspection be separate departments

23 Grouped operations and families of products

24 Queuing and space analysis for each family

25 Flow Analysis

26 Economic Analysis Plant cost: Cost of WIP at machines: Cost of WIP in material movement: Total Cost: