Consider a CONWIP flow line with 3 stations in series (1à 2 à 3); each station consists of one machine and every unit has to flow through all three stations before it is completed. [FYI, this problem is motivated by a simplified non-reentrant-flow version of the Littlefield game environment with station 1 as “board stuffing”, station 2 “testing”, station 3 “tuning”.] The unit processing times at the three stations are 2.8 hours, 4.2 hours, and 2.9 hours, respectively. (Aside: how would you determine the correct average processing time at station 1 for your Littlefield game?) There are 24 working hours in a day, and 5 working days per week. Currently there is a single machine at each station and the current demand is 3 units per day. Demand is expected to grow in the future and then stabilize; peak demand is estimated to be 15 units per day. Answer the following questions using the data specified.
a. Calculate the bottleneck rate, rb, the raw process time, T0, and the critical WIP, W0, for the current line
b. How much work-in-process inventory, w, is needed to make the practical worst case throughput for this line equal to 90% of the maximum possible throughput, i.e., to make THPWC = 0.9 rb?