3-22 A small manufacturing department contains three serial workstations (that is, parts go through each of the three workstations in order, one workstation after the other). Parts arrive according to an exponential interarrival-time distribution with mean 8 (all times are given in minutes), with the first part's arriving at time 0. Before a new part can start processing, it must be mounted on a special fixture, and this mounting operation takes 2 minutes (there are four fixtures available, which can be reused, but each fixture can carry only one part at a time). The part remains on the fixture until it completes processing on all the workstations, at which time it is removed from the fixture (this re- moval operations takes 1 minute), after which the fixture becomes available for another part that might be waiting for it. Processing times at the first workstation follow a tri- angular operation time with minimum 4, mode 7, and maximum 9. Processing times at the second workstation have a uniform distribution between 5 and 10. Processing times at the third workstation have a triangular operation time with minimum 5, mode 6.5, and maximum 9. Run your simulation for a single replication of length 48 hours, and observe the time-average and maximum total work in process (WIP) in the whole sys- tem. At each workstation separately, observe the average and maximum queue lengths, and the resource utilization. Also observe the utilization of the four fixtures as a group, as well as the time-average and maximum number of parts that are waiting for a fixture (before they can even get going into the system for processing). Add a plot for the total WIP and by-workstation queue lengths, all on the same set of axes; add a second plot showing the number of fixtures that are in use. Animate the resources and queues for each of the workstations, and animate the parts waiting for a fixture, but do not animate the fixtures themselves. Put in a text box with the numerical results requested. What ap- pears to be the bottleneck in this system preventing better efficiency? HINT: Remember that an entity can have multiple different resources Seized at the same time, and that the Process module has "Action" options other than the usual Seize-Delay-Release.

3-22 A small manufacturing department contains three serial workstations (that is, parts go through each of the three workstations in order, one workstation after the other). Parts arrive according to an exponential interarrival-time distribution with mean 8 (all times are given in minutes), with the first part's arriving at time 0. Before a new part can start processing, it must be mounted on a special fixture, and this mounting operation takes 2 minutes (there are four fixtures available, which can be reused, but each fixture can carry only one part at a time). The part remains on the fixture until it completes processing on all the workstations, at which time it is removed from the fixture (this re- moval operations takes 1 minute), after which the fixture becomes available for another part that might be waiting for it. Processing times at the first workstation follow a tri- angular operation time with minimum 4, mode 7, and maximum 9. Processing times at the second workstation have a uniform distribution between 5 and 10. Processing times at the third workstation have a triangular operation time with minimum 5, mode 6.5, and maximum 9. Run your simulation for a single replication of length 48 hours, and observe the time-average and maximum total work in process (WIP) in the whole sys- tem. At each workstation separately, observe the average and maximum queue lengths, and the resource utilization. Also observe the utilization of the four fixtures as a group, as well as the time-average and maximum number of parts that are waiting for a fixture (before they can even get going into the system for processing). Add a plot for the total WIP and by-workstation queue lengths, all on the same set of axes; add a second plot showing the number of fixtures that are in use. Animate the resources and queues for each of the workstations, and animate the parts waiting for a fixture, but do not animate the fixtures themselves. Put in a text box with the numerical results requested. What ap- pears to be the bottleneck in this system preventing better efficiency? HINT: Remember that an entity can have multiple different resources Seized at the same time, and that the Process module has "Action" options other than the usual Seize-Delay-Release.