Performance evaluation in Jsim
Assembly Process
Case Description
Stage | Technology | Input | Output | Duration |
1 | Adhesive joining | Component1, Component2 | WIP1 | Normal(10, 2) |
2 | Spot welding | WIP1, Component3 | WIP2 | Normal(5, 1) |
3 | Hemming | WIP2, Component4 | Final product | Normal(2, 1) |
The assembly process is a combination of three stages: Adhesive joining, Spot welding and hemming. And the Final product is a result of joining the four components: Component 1, Component 2, Component 3 and Component 4 where WIP1 and WIP2 are the intermediary outputs during the process. The table below defines the input, output and processing time of each stage.
But while modelling the system in JMT, we have eliminated the intermediary outputs WIP 1 and WIP 2. Instead we have assumed Final product to travel throughout the assembly process
Formal Model
Performance Evaluation
Modelling of the system
Open JSIM graph from the various tools in the home panel of JMT software
Select the source and sink icons in the toolbar and then place it in the workspace
Insert machines into the workspace by clicking the queue icon in the toolbar
Insert Fork and joins into the system by clicking on the above highlighted icons. All the 4 components gets divided at Fork 1 and they are routed accordingly
Customer Classes
Click on Add class button
All the components are selected as open type
Select fork as the reference station for the components
Select source as the reference station for the final product
Click on Edit button and select Exponential in order to record the interarrival time of final product
Enter the desired generation rate which is 1 part/second
Fork 1
Select Infinite capacity option under the queue section of Fork 1
Select Branch probabilities as the fork strategy for Component 1
Enter the probability as 1 for Join 1 and 0 for other two joins
Select Branch probabilities as the fork strategy for Component 2
Enter the probability as 1 for Join 1 and 0 for other two joins.
Select Branch probabilities as the fork strategy for Component 3
Enter the probability as 1 for Join 2 and 0 for other two joins
Select Branch probabilities as the fork strategy for Component 4
Enter the probability as 1 for Join 3 and 0 for other two joins
Select Multi Branch Class Switch as the fork strategy Final product. Here the final product is modelled throughout the process eliminating the intermediary outputs WIP 1 and WIP 2
Join 1
Select Standard join as the join strategy for all the components
Select Quorum as the join strategy for the Final product. Follow the same for all the joins
Select Disabled option as the routing strategy for the components 3 and 4
Select Probabilities as routing strategy for the Final product
Enter the probability as 1 for Adhesive joining
Adhesive joining
Select Infinite capacity option under the queue section of Adhesive joining
Select Disabled as the strategy for all the components under Service time distributions table
Select Load independent as the strategy for Final product and click Edit
Choose Normal distribution
Enter 10 as the mean and 2 as the standard deviation value
Select Random option as the routing strategy for the components
Select Probabilities as routing strategy for the Final product
Enter the probability as 1 for Join 2
Join 2
Select Disabled option as the routing strategy for the components 1,2 and 4
Select Probabilities as routing strategy for the Final product
Enter the probability as 1 for Spot welding
Spot welding
Select Disabled as the strategy for the components
Select Load Independent as the strategy for Final product. Enter normal(5,1) as the service time
Select Probabilities as routing strategy for the Final product and Random for the components
Enter the probability as 1 for Join 3
Join 3
Select Disabled option as the routing strategy for the components 1,2 and 3
Select Probabilities as routing strategy for the Final product
Enter the probability as 1 for Hemming
Hemming
Select Disabled as the strategy for the components
Select Load Independent as the strategy for Final product. Select normal distribution and enter 2 as mean and 1 as standard deviation
Select Probabilities as routing strategy for the Final product and Random for the components
Enter the probability as 1 for Sink
Performance Indices
Click on Select an index drop down box and choose Throughput per sink and Utilization as indices
Select Final product as the class and Sink as the station
Select all the three stations in order to find the utilization
Simulation results
Utilization of :
Adhesive joining = 1
Spot welding = 1
Hemming = 1
Throughput of the system = 0.4851
Last updated
