• Process characteristics:
  • Average demand: 5,000 per day, 3,500 larger, 1,500 small
  • Batch size: 1,100
  • Number of shifts per day: 2
  • Shift: 8 hours with 30 minute lunch
• Shipments:
  • One shipment of 5,000 per day
• Information flow:
  • Electronic communication of forecasts to supplier
  • Electronic communication of daily orders from customer
  • Electronic communication of forecasts from customer
  • Electronic communication of daily shipping schedule to process step 4
  • Electronic communication of weekly schedule to process steps 13
  • All material is pushed

1. Using the data shown in the table, construct a value stream map for Yahoo Widgets, Inc.
   • See list of steps above. Important: For the purposes of this assignment, show the setup (changeover time) for each activity and note the batch sizes on your map, but they do not impact your calculations.
2. What is the takt time of the manufacturing cell?
   • Manufacturing cell refers to this entire process from end to end. Takt time is the available production time divided by customer demand. For example, if a widget factory operates 480 minutes per day and customers demand 240 widgets per day, takt time is two minutes. Make sure to clearly state any assumptions. Takt time is relevant because, in theory, this is the perfect rate at which to produce to exactly meet customer demand.
3. What is the production lead time for each process step?
   • Calculate the lead time for each of the steps. From Chapter 6, recall that lead time is the time needed to respond to a customer order. In terms of lean, this means that lead time includes buffer time and processing time. You can add up the time associated with each buffer and the step that follows it to get a lead time for each step. If you add up all of the times all buffers and all activities across the entire process you get the lead time for the entire process.
   • Important: Based on how this question is worded, please provide a time for each of the 3 steps, and an overall time for the entire process.
   • Note that filling out your timeline at the bottom of the map is important for answering this question. To see an example of how to calculate buffer time for each inventory point noted in the process data, see Exhibit 12.2 in Chapter 12. Notice that 504 pieces/day are shippedthis is the rate at which the process operates currently. The first inventory buffer on Exhibit 12.2 is 5,040 pieces, which equates to 10 days of supply (see the 10 days on the timeline) for this process.
4. What is the total processing time for the manufacturing cell?
   • Processing time is the same as value-adding time. You have three processes for which times are provided; since these are all averages you can add them up to produce a total.
5. What is the total capacity of the manufacturing cell?
   • For the purposes of this assignment, you can calculate capacity for a single operating day how many widgets can Yahoo make in a day. Keep in mind that what constitutes an operating day depends on the process. You have been given information about the length of an operating day for this process.
   • The capacity is constrained by the available operating time. Make sure to take into account how many shifts run, and for how long, as well as equipment downtime.
   • Capacity is also constrained by the pace of the slowest processing activity. This activity is also known as the bottleneck. The process as a whole cannot produce any faster than the bottleneck.

Process StepsStep NameStep DescriptionProcess Step 1Thermo-form

• Cycle time = 15 seconds
• Set-up time = 15 minutes
• Up time = 85%
• Operators = 2
• Every part every week
• WIP = 5 days of sheets in front of the Thermo-forming machine

Process Step 2Drill

• Cycle time = 32 seconds
• Set-up time = 25 minutes
• Up time = 80%
• Operators = 4
• Every part every week
• WIP = 1,250 larger, 1,500 small

Process Step 3Grind, Sand

• Cycle time = 22 seconds
• Set-up time = 27 minutes
• Up time = 75%
• Operators = 5
• Every part every week
• WIP = 1,750 large, 1,250 small

Process Step 4Pack and Ship

• WIP = 750 large, 125 small