A production line operates 18 -hour shift(s) for 241 days per year and must annually produce 900,000 good quality parts of various designs in batch sizes of 9,000 parts to satisfy the plant's delivery schedule. Scrap rate is expected to be 3%. On average it takes 3min. to produce each part when the automated production machines are running. Before each batch, the machine must be set up, and that takes 2 hours per setup. Availability of the machines is 96.5% during production and 98.5% during setup. How many automated production machines will be required to accomplish the specified production