Chapter 12 HW Calculate Lead Time Williams Optical Inc. is considering a new lean product cell. The present manufacturing approach produces a product in four separate steps. The production batch sizes are 67 units. The process time for each step is as follows: Process Step 1 7 minutes Process Step 2 Process Step 3 5 minutes 4 minutes 9 minutes Process Step 4 The time required to move each batch between steps is 11 minutes. In addition, the time to move raw materials to Process Step 1 is also 11 minutes, and the time to move completed units from Process Step 4 to finished goods inventory is 11 minutes. The new lean layout will allow the company to reduce the batch sizes from 67 units to 4 units. The time required to move each batch between steps and the inventory locations will be reduced to 2 minutes. The processing time in each step will stay the same. Determine the value-added, non-value-added, and total lead times, and the value-added ratio under the present and proposed production approaches. If required, round percentages to one decimal place. Present Approach Proposed Approach Value-added time min min Non-value-added time min min Total lead time. min min Value-added ratio (as a percent) % %