Optimizing the Camshaft Incoming Inspection by Simulation Modeling

As is known, during fault inspection, up to 35% of camshafts are rejected as unrepairable, of which 50% are because of cam wear (2/3) and bearing journal wear (1/3). The remaining defects are distributed relatively uniformly. Since this statistics has been collected on the basis of a large data set and may not correspond to a particular enterprise, it is impossible to build a universal model. Notations can graphically represent the process and provide its simulation modelling to identify vulnerabilities. A typical example of the notations is the BPMN. To increase the productivity of the camshaft fault inspection, two models in the BPMN notation have been constructed: the uniform distribution of the defect detection probability over operations and the nonuniform probability distribution according to the statistics. The simulation modelling of the fault inspection of 100 camshafts of a YaMZ-236 engine built in the BPMN notation has been carried out using the Business Studio software. In the real process, the parameters of 100 shafts have been controlled with universal and specialized measuring instruments under the conditions of an AB-Engineering specialized repair enterprise. The comparison of the real process with its model has yielded closer results at the nonuniform distribution, which has been taken into account during the optimization. The input inspection has been optimized based on the percentage of rejected products and the operation time. The time of the fault inspection after the optimization has been reduced by a factor of 1.35 and the discrepancy between the model and the real process data has been no more than 5%, which is indicative of the correctness of an approach used to model the processes characterized by a high degree of uncertainty.