Problem 1

Albert’s is a company that manufactures brake discs. The final stage of production is to machine the brake discs to specification, which is completed on a lathe. There are 6 lathes, and the processing time of each break disc is 40 minutes. Assume that there are in total 340 working days per year. What is the annual process capacity with two eight-hour shifts each day?

Problem 2

In a bank there are two bank tellers behind the window. The demand rate is 43 customers per hour.

Answer the following questions. 1) What is the processing time per customer per bank teller (in minutes) if the utilization is 90%?

2) If the utilization is 90% and the processing time per customer per bank teller is 5 minutes, at least how many bank tellers are needed to handle the customers given the demand rate above?

Problem 3

The Wilcox Student Health Center has just implemented a new computer system and service process to “improve efficiency.” The process flowchart and analysis framework is also provided. As pharmacy manager, you are concerned about waiting time and its potential impact on college students who “get no respect.” All prescriptions (Rxs) go through the following process: Assume that students arrive to drop off Rxs at a steady rate of 3 Rxs per minute, with an average of one Rx per student. The average number of students in process (assume waiting and being serviced) at each station is: Drop-Off—7 students, Pickup—5 students, and Pay Cashier—8 students. The fill Rx station typically has 60 Rxs in process and waiting, on average. Because of this perceived long wait, 75 percent of the students decide to come back later for pickup. They come back an average of 5 hours later. If the students choose to stay, each name is called as soon as the Rx is filled, and the student then enters the pickup line. Assume that the system is operating at a steady state.

1) What is the average time a student spends in the pharmacy if he or she stays to pick up the Rx? 2) How many minutes does the student spend in the pharmacy if he or she picks up the Rx 5 hours later (i.e., the student goes home after dropping the Rx off)? 3) What is the average time in minutes that all students spend in the pharmacy? 4) What is the average time in minutes that the Rx spends in the process? Count time from entering the drop-off line to completing payment.

Problem 4

Consider a four-step serial process with processing times given in the following list. There is one machine at each step of the process, and this is a machine paces process.

Step 1: 25 min per unit

Step 2: 15 min per unit

Step 3: 30 min per unit

Step 4: 20 min per unit

Assuming that the process starts out empty, how long will it take (in hours) to complete a batch of 105 units?