1. An average of 20 new orders are started through a certain factory each month. On average, an order consists of 50 parts to be processed through 10 machines in the factory. The operation time per machine for each part=15 min. The non operation time per order at each machine averages 8 hr, and the required setup time per order=4 hr.There are 25 machines the factory, 80% of which are operational at any time (the other 20% are in repair or maintenance). The plant operates 160 hr/mo. However, the plant manager complains that a total of 100 overtime machinehours must be authorized each month to keep up with the production schedule. (a) What is the manufacturing lead time for an average order? (b) What is the plant capacity (on a monthly basis) and why must the overtime be authorized? What is the utilization of the plant according to the definition given in the text? (d) Determine the average level of work-in-process (number of parts-in-process) in the plant.

2. The mean time between failure for a certain production machine is 250 hr, and the mean time to repair is 6 hr. Determine the availability of the machine.

3. One million units of a certain product are to be manufactured annually on dedicated production machines that run 24 hr/day, 5 day/wk, 50 wk/yr. (a) If the cycle time of a machine to produce one part is 1.0 min, how many of the dedicated machines will be required to keep up with demand? Assume that availability, utilization, and worker efficiency=100%, and that no setup time will be lost. (b) Solve part (a) except that availability=0.90.