NOTE: This assignment provides a relevant example of a simulation in the context of manufacturing instead of a capital projects problem. Use your knowledge gained from Modules 6 and 7 in developing your simulation model in Arena. Consider a manufacturing system comprising two different machines and one shared operator. The single operator is shared between the two machines. Parts arrive with an exponentially distributed inter-arrival time with a mean of 3 minutes. The arriving parts are one of two types. Sixty percent of the arriving parts are Type 1 and are processed on Machine 1. These parts require the assigned operator for a one-minute setup operation. The remaining 40 percent of the parts are Type 2 parts and are processed on Machine 2. These parts require the assigned operator for a 1.5-minute prep and setup operation. The service times (excluding the prep and setup time) are lognormally distributed with a mean of 4.5 minutes and a standard deviation of 1 minute for Type 1 parts and a mean of 7.5 minutes and a standard deviation of 1.5 minutes for Type 2 parts. Run your model for 20000 minutes, with 20 replications. Report the utilization of the machines and operators, and report the total time spent in the system for each type of part. Complete two options for the model and report statistics on both. Then comment on the differences in the utilizations and system times. 1. Option 1 – Only the operator is needed for prepping and setting up the part. Parts are automatically fed onto the machine and do not require the operator for that task. And the operator can prep and setup many parts even if the machine is busy. 2. Option 2 – You need both the operator and machine to be available before the prep and setup can be performed. Then you only need to keep the machine busy for processing time on the machine. Other comments: • Operators and machines are considered resources in both options. While parts are automatically fed onto the machine in Option 1, it still requires the machine to be available in order to process the part. • Implement the traditional sense in how resources were modeled in Lecture 3, Module 6, Lecture 3 as opposed to and Module 7, Lecture 1. The excavator and dump truck example was a unique way to model the excavator resource as an entity itself.
