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Similar to Discrete Event Simulation Analysis of a Gearbox Manufacturing Plant Using the Software ‘Witness’
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Discrete Event Simulation Analysis of a Gearbox Manufacturing Plant Using the Software ‘Witness’
- 1. ENGINEERING SIMULATION COURSEWORK 2; PDE 4905 May 1, 2015 9 Middlesex University, London School of Science and Technology PDE 4905 Engineering Simulation Coursework For the Academic Year 2014-2015 Rifat Abdul Rahiman M00514416
- 7. ENGINEERING SIMULATION COURSEWORK 2; PDE 4905 May 1, 2015 T Breakdown One of the common occurrences in the manufacturing sector is the breakdown of equipments and units. Multiple breakdowns of units can be set in Witness which has to be done through proper distribution. According to the description a 90 minutes breakdown has to be considered in the system, which indicates the time required to repair the specified unit. A Breakdown counter has been used and defined to indicate the number of breakdowns that occur. The time taken between each breakdown for the conveyor belt and the CNC machine is 8000 and 4000 respectively. Its function is defined as Breakdown_counter = Breakdown_counter+1 Results The required model was created and simulation was done to an optimum level manually to observe and analyse the performance. The Revenue for the plant was deduced by manually setting up the plant at different conditions within the given budget o £ 15000. This was done by using several variables, functions and variables along with the manufacturing unit like the inspection and assembly base. Operators were assigned uniform shifts with a maximum of 8 hours per day. The system was run for 14400 minutes to obtain the results, and out of 6 different calculations as given below, the combination that gave the maximum revenue for two weeks was £43964 for a budget of £13700. One of the tasks required was to identify the characteristics of the system after and before each of the machines or unit has broken down. Number of Shipments Operator Shift Quantity Assembly Quantity Bin Quantity Conveyor Belt Quantity Test Bench Quantity Test Buffer Quantity CNC Quantity Budget Revenue 585 1 2 1 1 2 1 2 9700 41324 620 1 3 1 1 2 1 3 11500 42132 585 2 2 1 1 2 1 3 11200 38096 620 1 3 1 1 3 1 2 13700 43964 605 1 3 1 1 3 1 3 13700 40844 555 1 1 1 1 1 1 1 5700 41004 Table1. Revenue and Budget Statistics One of the tasks required was to identify the characteristics of the system after and before each of the machines or unit has broken down. Understanding the breakdown characteristics and its aftereffects will assist in managing the system and reduce the risk associated with it. This is highly helpful in maintaining the income as well. It is to be noted that when any one part of the system breaks down, it affects the whole setup completely. The conditions for the breakdown as mentioned earlier are set in system and the performance for each unit was investigated before and after the breakdown. The data and statistics for each of the units are given below.
- 14. ENGINEERING SIMULATION COURSEWORK 2; PDE 4905 May 1, 2015 9P Discussion The simulated results obtained for the system modelled using Witness was analysed which give an idea about its characteristics. It was found that through manual calculations setting the budget within the required 15000 pounds limit, a maximum revenue of 43964 pounds was achieved when using 3 assemblies and test benches along with 2 CNC machines. In addition a conveyor belt was used. A budget of 13700 pounds was used in this case. Using Witness and through optimization excellent forecasts can be achieved for the revenue and budget which gives a good indication on what business model to use and proceed to improve and maximize the income. Nevertheless it is only a forecast and is liable to change when compared with the performance in the real world as the values can end up being higher or lower than the initial forecast. The breakdown statistics was also observed during the analysis to understand its impact on the system. The plant is affected hugely when any one of the units breakdown especially the conveyor belt and the CNC machine because they are the units from which the system starts to work. The plant tends to become idle when they breakdown as shown in the data given earlier. This in addition has an adverse impact on the revenue of the plant as well. Also the reduced number of shipped gearboxes can also be seen from the data after the different sections have undergone a breakdown, when compared with their data prior to breakdown. Even though the breakdown statistics for each machine is valuable and has to be considered, like the optimization of the software, it doesn’t incur the real time aspects and tends to be different in the real world compared to the system. Conclusion The model was designed using the simulation software Witness and the maximum revenue obtained for a period of two weeks was 43964 pounds for a budget of 13700 pounds. This indicates that the plant can incur a revenue of 402300 pounds per year based on the forecast, which actually is a respectable amount of income when considering the requirements for the plant. Moreover from the detailed analysis of breakdown, specifically the breakdown counter it can be seen that there is always one breakdown in the plant every week. This shows that the average number of breakdown the plant is expected to suffer in a year is 52. When the machines or units break down, especially the CNC and conveyor belt, the complete plant is affected and is subjected to idleness and blockage in different machines. Nonetheless these results are not precise as they don’t consider the human, external or supply and demand factors which also play a huge role on the working of the industries and focusing solely on the simulated forecast can also lead to poor performance.