Waiting times, manufacturing lead times. The SRG Corporation uses an injection moulding machine to make a plastic product, Z39. SRG makes products only after receiving firm orders from its customers. SRG estimates that it will receive 50 orders for Z39 (each order is for 1,000 units) during the coming year. Each order ofZ39 will take 96 hours ofmachine time

(4.8 hours to clean and prepare the machine, called setup, and 91.2 hours to process the order). The annual capacity of the machine is 6,000 hours.

Required 1. What percentage of the total available machine capacity does SRG expect to use during the coming year?

2. Calculate the average amount of time that an order for Z39 will wait in line before it is processed and the average manufacturing lead time per order for Z39.

3. SRG is considering introducing a new product, Y28. SRG estimates that, on average, it will receive 25 orders of Y28 (each older for 200 units) in the coming year. Each order of Y28 will take 24 hours of machine time (2.4 hours to clean and prepare the machine, and 21.6 hours to process the order). The average demand for Z39 will be unaffected by the introduction of Y28. Calculate the average waiting time for an order received and the average manufacturing lead time per order for each product, if SRG introduces Y28.

4. If SRG introduces Y28, on average what fraction of the total manufacturing lead time will each order of Y28 spend just waiting to be processed?

5. Briefly describe why delays occur in the processing ofZ39 and Y28.