ENM 307 SIMULATION
In a manufacturing system, there are two parts arriving in:
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Part A: inter-arrival times are exponentially distributed with a mean of 5 minutes,
Part B: inter-arrival times are exponentially distributed with a mean of 30 minutes and in
batches of 4.
Both parts enter to a pressing process, but before that they have to be prepared:
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Part A requires a preparation server called Prep A. Service time of server Prep A is
Triang(1,4,8).
Part B requires a server called Prep B. Service time of server Prep B is Triang(3,5,10).
After preparation, both parts enter to the pressing process. There is only one server in the
pressing process and the two parts requires different service times:
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Part A requires a service time with Triang (1,3,4)
Part B requires a service time with Weibull (2.5,5.3)
After the pressing process, both parts enter to an inspection process. Past data reveal that 91%
of the parts pass the inspection and are shipped whereas 9% of parts fail and enter to a rework
process.
There is only one server for the rework process. Rework time is exponential with a mean of 45
minutes for both of the parts. If the rework process takes less than or equal to 50 minutes, rework
is considered as successful and the part is called as “Salvaged Part”
On the other hand, if the rework process takes longer than 50 minutes, it stops at the 50th minute
and the part is called as “Scrapped Part”.
Simulate the system for 100 hours to estimate the following performance measures:
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average amount of time spent in the system by shipped parts, salvaged parts and
scrapped parts, as well as by Part A and Part B,
average waiting time of Part A and Part B,
average utilizations of Prep A, Prep B, Press Machine and Rework Machine.