Modeling And Optimization Of Mold Production Process Based On Petri

In recent years,competition between the enterprises is bigger and bigger due to the transformation of production mode and domestic and overseas market.The market has become globally,customer has higher expectations on both products' delivery and cost,so small and medium-sized enterprise stepped into a fast lane,such as mold factory,they have meet the increased request of shorter delivery,emergency orders,the competition between enterprises has changed from time-based competition to competition based on customer requirements.According to these challenge status,potential conflict began to emerge in the company,it becomes the obstacle for the development of the company.Therefore,the new subject of finding root cause of conflict,solving the problem,optimizing the process to meet the delivery date,especially finding the opportunity has become a hot topic which experts are facing in recent years.This article researched present situation after investigating and surveying EVT mould company,including existing technology and experience background,reference research status domestic & overseas market.Petri net has formal semantics,visualized graphical representation,strong ability of expression,especially it has a clear expression of the process,which the main reason is based on the Petri nets to analysis and optimization process,Firstly start with the basic theoretical knowledge introduction of Petri nets,elaborates theoretical knowledge Petri nets by linking together simple model of actual process and Petri net concepts,Key parsing Petri modeling process in the actual production process and analysis method,define the content and function of Petri net elements: Place and Transition,Set up Petri model according to the specific process of EVT mould company,establish incidence matrix and workout S – invariants,analysis the basic properties of the model according to the definition.After then,analysis the correlation matrix,it is concluded that the matrix have four lines contains two Numbers "1",that means there are conflicts here,two Transition need to trigger with same Place resources,the one which can get resources will have normal flow through a transition with a normal operation,the one which failed to get resources will wait or cannot finish tasks before move to next Place,in actual process,it will appear waiting and preempting the location due to lack resources of the next change,Finally optimize the conflict point in Petri net,set up new Petri net model.The optimizing principle is adding a new Place to conflict point,eliminate the conflict by change the conflict to synchronous structure.In actual process the method is to decompose the conflict by adding the task dispatching into process,avoid waiting and resource shortage problem.Set up Place and Transition invariant matrix of new Petri net,analysis the performance of Reachable,Liveness and Boundness.Parallel structure be intruded into model,on Transition will trigger two Place happened,so there is no conflict in process,and also the productivity be increased accordingly.