eBook 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 71 units. The process time for each step is as follows: Process Step 1 Process Step 2 Process Step 3. Process Step 4 7 minutes 5 minutes 9 minutes 4 minutes 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 71 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 Non-value-added time Total lead time 25 min 25 mint mini min min min Value-added ratio (as a percent) % % Previous Next >