3. The Impact of Set-ups on Capacity Production cycle Batch of 12 Production cycle Batch of 60 Batch of 120 Batch of 300 Time [minutes] 60 240 300 120 180 Produce steer supports (1 box holds 12 units = 12 scooters) Set-up from ribs to steer support Produce ribs (1 box holds 24 units = 12 scooters) Set-up from steer support to ribs
6. Creates an inherent mismatch between demand and supply0.5 Capacity 1/p 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Batch Size 10 50 90 130 170 210 250 290 330 370 410 450 490 530 570 610 650 Process Analysis with Batching
7. Batch Flow Operations Carry a Lot of Inventory Produce Sedan Produce Station wagon Production with large batches Production with large batches Production with large batches Production with large batches Production with small batches Production with small batches Production with small batches Production with small batches Cycle Cycle Cycle Cycle Cycle Cycle Cycle Cycle Inventory Inventory Inventory Inventory Inventory Inventory Inventory Inventory Produce Sedan Produce Sedan Produce Sedan ISedan IWagon Produce Station wagon Produce Station wagon Produce Station wagon ISedan IWagon End of Beginning of End of Beginning of End of Beginning of End of Beginning of End of Beginning of End of Beginning of End of Beginning of End of Beginning of Month Month Month Month Month Month Month Month Month Month Month Month Month Month Month Month Movie theater vs. a room full of DVD players SMED (Single minute exchange of die): reduce set-up times
8. 6.1 Metal window boxes are manufactured in two process steps: stamping and assembly. Each window box is made of 3 pieces: base A and two side Bs. These parts are fabricated by a stamping machine with a setup time of 2 hours whenever switching between the two part types. Once the machine is set up, the activity time for part A is one minute and for part B is 30 seconds. The current rotation is 360 As to 720 Bs. Completed parts move from stamping to assembly once a batch is complete. At assembly, one A, two Bs and some purchased parts are required per finished unit. Each product requires 27 minutes of labor to assemble; there are 12 workers in assembly; there is sufficient demand to sell every box produced. What’s the capacity at stamping? What should the batch size be?
9. Step 1 Step 2 Step 3 Activity Time 0.25 min/part Setup Time 30 min Activity Time 0.20 min/part Setup Time 20 min Activity Time 0.15 min/part Setup Time 45 min 6.3 Consider the following batch-flow process consisting of 3 process steps performed by 3 machines. Work is processed in batches at each step. Before a batch is processed at a step, the machine must be set up during which it is unable to produce. Each machine has a dedicated setup operator. What is the capacity of step 1 if the batch size is 35? For what batch sizes is step 1 (2,3) the bottleneck?
