A food-processing system starts by processing a 25-pound batch of raw of product, which requires 1.05 + WEIB(0.982, 5.03) minutes. Assume an inf nite supply of raw product. As soon as a batch has completed processing, it is removed from the processor and placed in a separator where it is divided into 1-pound units. The separation process requires 0.051 minute per pound. Note that this is not a “batch process,” but rather in each 0.05 time unit a 1-pound unit is completed. These 1-pound units are sent to one of the three wrapping machines. Each wrapping machine has its own queue, with the unit being sent to the shortest queue. The wrappers are identical machines, except for the processing times. The wrapping times are constants of 0.20, 0.22, and 0.25 minute for wrappers 1, 2, and 3, respectively. The wrapped products are grouped, by wrapper, into batches of six for f nal packaging. Once a group of six items is available, that group is sent to a packer that packs the product, which takes 0.18 1 WEIB(0.24, 4.79) minutes. These packages exit the system. Assume all transfer times are negligible.

(a) Develop a simulation and animation of this system and run it for 1,000 minutes, observing statistics on resource utilizations, queues, and the total number of packages shipped.

(b) Modify your model to include wrapper failures with the following characteristics for all wrappers: EXPO(20) for uptimes and EXPO(1) for repair times.

(c) Add a quality check to your model from part (b). Every half hour, a scan is made, starting with the f rst wrapper queue, for products that are more than 4 minutes old; that is, that exited the processor more than 4 minutes ago. Any such items are removed from the queue and disposed. It takes 3 seconds to f nd and remove each item. Keep track of the number of units removed.