1) At Dorben Company, a worker is assigned to operate several machines. Each of these machines is down at random times during the day. A work sampling study indicates that, on average, the machines operate unattended 60 percent of the time. Operator attention time at irregular intervals averages 40 percent. If the machine rate is $20/h and the operator rate is $12/h, what would be the most favorable number of machines (from an economic standpoint) that should be operated by one operator?
2) The current operation consists of the following elements: Operator removes pressed unit (0.2 min).Operator walks to inspection area, checks for defects (0.1 min). Operator files rough edges (0.2 min).Operator places unit on conveyor for further processing and returns to press (0.1 min). Operator cleans press die element with compressed air (0.3 min). Operator sprays lubricant into die (0.1 min). Operator places sheet metal into press, pushes START (0.2 min). Press cycles automatically for 1.2 min. Given that the operator is paid $10/h and that presses cost $15/hr to run, find and draw the worker-machine chart for the lowest-cost operation. What is the produc- tion? What is the unit cost?