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 $75$ units. The process time for each step is as follows:

Process Step $17$ minutes

Process Step $25$ minutes

Process Step $34$ minutes

Process Step $49$ minutes

The time required to move each batch between steps is $14$ minutes. In addition, the time to move raw materials to Process Step $1$ is also $14$ minutes, and the time to move completed units from Process Step $4$ to finished goods inventory is $14$ minutes.

The new lean layout will allow the company to reduce the batch sizes from $75$ units to $5$ 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.