Design & Sim. of Mfg. Systems/Mfg Syst Design & Simulation-SP18-001

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Mfg Syst Design & Simulation – Lab 2

Student must complete this lab individually.

There are three problems in this lab.

Please submit the following files to D2L dropbox:

1) Arena simulation model files. 2) MS Word files (Memo Format).

Problem 1

When a vehicle is returned to an airport rental vehicle agency, the vehicle is processed through an automated vehicle wash. The automated vehicle cleans two types of vehicles – cars and minivans. A car arrives every 10 minutes (exponentially distributed) and requires between 3 and 5 minutes (uniform distribution) to go through the wash system. The first car arrives at time 0. The first minivan arrives at time 5 and continues to arrive at an average of every 7 minutes thereafter (exponentially distributed). Each minivan requires 5 minutes to go through the wash system (normally distributed with standard deviation of 0.5 minute). Only one vehicle can be in the wash system at any one time. If both a car and a minivan are waiting for the car wash, the minivan will always be given priority to be the next vehicle to be washed.

Create the simulation model with Arena. Run your simulation for 600 minutes and collect the following statistics:

1. The average time for a car in the car wash system (from arrival to departure). 2. The average time for a minivan in the car wash system. 3. The average number of vehicles waiting to be washed. 4. The average time a vehicle waits in the queue before beginning its wash. 5. The utilization of the automated car wash. 6. The average wash time of car and the average wash time of a minivan.

Please report your answer in the Memo format (refer to the “Example Memo” Document).

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Problem 2

Consider a manufacturing system comprised of two different machines and a single operator who is shared between them. The only function of the operator is to set-up the machines. Parts arrive following an exponential distributed interval time with a mean of 6 minutes. An arriving part is one of two types. Forty percent of the arriving parts are Type 1 and are processed on Machine 1. These parts require the operator for a 45 seconds set-up operation (constant). The remaining 60% are part Type 2 and processed on Machine 2. These parts require the operator for a one minute set-up operation. The service times (excluding the set-up time) for machines are,

1. Normally distributed with a mean of 10 minutes and a standard deviation of 1.5 minute for Type 1 parts, and,

2. Normally distributed with a mean of 7.5 minutes and a standard deviation of 2 minutes for Type 2 parts.

Assume the operator is only requested for setting up the machine when the machine is free. Also, suppose that the priority scheme for allocating the operator is to give priority to Type 2 jobs. Under this proposal, a job Type 1 set-up will only be performed if there are no job Type 2 set- ups waiting to be performed.

Using Arena, simulate this system for a 10 hour period and collect the following statistics,

1. The utilization of the single operator. 2. The utilization of Machine 1. 3. The utilization of Machine 2. 4. The average number of parts waiting in Machine 1 queue. 5. The average number of parts waiting in Machine 2 queue. 6. The average total time that a Type 1 part is in the production system. 7. The average total time that a Type 2 part is in the production system.

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Problem 3

During its final stages of production, assembled television set move through an inspection station where the control setting on the television is tested. If the setting is found to be functioning improperly, the offending television set is routed to an adjustment station where the setting is adjusted. After adjustment, the television set is sent back to the inspection station, where the setting is again inspected. Television sets that pass the inspection (whether for the first time or after one or more routing through the adjustment station) are routed to a packing area. The time between arrivals of televisions set to the inspection station is uniformly distributed between 3.5 and 7.5 minutes. It takes 30 seconds for the television to be routed to the inspection station. Two workers are available for inspecting televisions at the inspection station (however, only one is required to perform inspection job, hence, the two workers can inspect two different televisions at the same time). The time required for a worker to inspect a television set is normally distributed with a mean of 8 minute and a standard deviation of 3 minutes. On average, 80% of the television sets pass inspection and continue on to the packing area. The other 20% are routed to the adjustment station which is managed by a single worker (there are total three workers in this working area two work for inspection and one works for adjustment). Adjustment of the control setting (at the adjustment station) requires between 15-25 minutes, uniformly distributed.

Using Arena, simulate this system for an 8 hour period and collect the following statistics,

1. Utilization of the workers at the inspection station. 2. Utilization of the worker at the adjustment station. 3. The number of televisions that need to be adjusted. 4. The average inspection time for the televisions. 5. The average time a television waits in the adjustment station queue. 6. The average number of televisions in the entire system.