A six-station dial indexing machine is designed to perform four assembly operations at stations 2 through 5 after a base part has been manually loaded at station 1. Station 6 is the unload station. Each assembly operation involves the attachment of a component to the existing base. At each of the four assembly stations, a hopper-feeder is used to deliver components to a selector device that separates components that are improperly oriented and drops them back into the hopper. The system was designed with the operating parameters for stations 2 through 5 as given in the table below. It takes 2 sec to index the dial from one station position to the next. When a component jam occurs, it takes an average of 2 min to release the jam and restart the system. Line stops due to mechanical and electrical failures of the assembly machine are not significant and can be neglected. The foreman says the system was designed to produce at a certain hourly rate, which takes into account the jams resulting from defective components. However, the actual delivery of finished assemblies is far below that designed production rate. Analyze the problem and determine the following:
(a) The designed average production rate that the foreman alluded to.
(b) What is the proportion of assemblies coming off the system that contain one or more defective components?
(c) What seems to be the problem that limits the assembly system from achieving the expected production rate?
(d) What is the production rate that the system is actually achieving? State any assumptions that you make in determining your answer.

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Feed rate f 32/min 20/min 20/min Station Assembly time 4 sec sec sec sec Selector θ 0.25 0.50 0.20 1.0 0.01 0.005 0.02 0.01 72 1.0 0.6 1.0 0.7 5 min