Question

The Yum and Yee food truck near the business school serves customers during lunch hour by taking orders and making fresh batches of stir fry. Customers have only one choice during the lunch hour, since the objective is to maximize the number of customers served. Assume that each customer places just one lunch order, and all lunch orders are the same size –one unit of stir-fry. The stir fry cooking works in this manner. First, a batch of orders is cooked in a wok by one person. The cooking depends upon the number of orders in the batch. The time to cook just one order is 3 minutes. For each additional order in the batch, it takes 0.5 minutes more to cook. Thus, cooking two orders in a batch takes 3.5 minutes, cooking three orders takes 4 minutes, and so on. The other activity is bagging and accepting payments (done by a separate person), which takes 0.80 minutes per order.

If Yum and Yee operates with batch sizes of 9 units, what is their process capacity (in orders per miute)?

Answer 1

To be calculated:

Process capacity

Given values:

Time to cook one order = 3 minutes

Time for every additional order = 0.5 minutes

Therefore, Set-up time for the process = Time to cook one order - Time for every additional order

Set-up time for the process = 3 minutes - 0.5 minutes = 2.5 minutes

Time for bagging and accepting payments = 0.80 minutes per order

Batch size = 9 units

Solution:

The process capacity for cooking is calculated as;

Setup time = 2.5 minutes

Processing time per order = 0.5 minutes

Number of units produced in one batch = 9 units

Process capacity = Total units produced / Total time taken

Process capacity = 9 / [2.5 + (0.5 x 9)]

Process capacity of cooking = 9 / 7 = 1.29 orders per minute

The process capacity for bagging and accepting payments is calculated as;

Process capacity = Total units produced / Total time taken

Process capacity of bagging and accepting payments = 1 / 0.80 = 1.25 orders per minute

The overall process capacity is the capacity of bagging and accepting payments (bottleneck) = 1.25 orders per minute

Process capacity = 1.25 orders per minute