Kristen and her roommate are in the business of baking custom cookies. As soon as she receives an order by phone, Kristen washes the bowl and mixes dough according to the customer's order activities that take a total of 6 minutes. She then spoons the dough onto a tray that holds one dozen cookies (2 minutes). Her roommate then takes 1 minute to set the oven and place the tray in it. Cookies are baked in the oven for 9 minutes and allowed to cool outside for 5 minutes. The roommate then boxes the cookies (2 minutes) and collects payment from the customer (1 minute).
a. Draw a flowchart for the process described here and determine theoretical flow time from the time of order until the time of payment collection. Assume no waiting over the course of the process.
b. Suppose that each order consists of two dozen cookies. Assume that although the mixing bowl can accommodate dough for two dozen cookies at a time, the oven can accommodate only one tray of one dozen cookies at a time. As before, spooning each tray takes 2 minutes, and both trays must be cooled prior to boxing the cookies for customer pickup. Draw a modified flowchart and determine theoretical flow time. Consider the effect on flow time of the following possible alternatives to the system:
1. Buying a second oven that can bake one tray of one dozen cookies
2. Buying a second oven that can hold two trays of one dozen cookies each
3. Buying a faster convection oven that can bake one dozen cookies in 6 minutes instead of 9 minutes.