Risk Assessment Of Product Quality Of Complex Manufacturing Systems Based On Fuzzy Petrinets

At present,our country is changing from a big manufacturing country to a strong manufacturing country.The so-called ‘strong’ is not only a strong production capacity,but also an excellent product quality.This is the key to determining the competitiveness of an enterprise.With the improvement of people’s living standards,th e demand for product diversity increases,and the manufacturing system becomes more and more complex,leading to an increase in factors affecting product quality.How to evaluate the product quality in a complex manufacturing system so as to prevent the oc currence of product quality problems and reduce the product unqualified rate has become an urgent problem for manufacturing companies.Based on this background,this thesis studied the method of product quality risk assessment in complex manufacturing syst ems,selected the evaluation indicators of complex manufacturing systems,established a fuzzy Petri net model for risk assessment,and conducted the research on the vehicle manufacturing system of Company Z.Instance verification.The specific research con tent was as follows:Firstly,this thesis analyzed the current situation of Z company’s vehicle manufacturing system and its quality management,and applied the idea of risk management to product quality management,and pointed out the necessity of quality risk management for complex manufacturing systems.Combining the large number and wide distribution of risk factors affecting product quality in complex manufacturing systems,this thesis used a combination of flowchart method and expert brainstorming method to analyze the risk factors affecting product quality in the system,and established a risk evaluation index system.Secondly,aiming at the human subjectivity of the subjective weighting method and the mechanical objectivity of the objective weightin g,by linearly weighting the weighting results of the analytic hierarchy process and the entropy weighting method,In this thesis,the indicator weights were allocated reasonably,and the evaluation indicators were assigned weights according to the status quo of the Z company.Thirdly,because fuzzy Petri nets can visually represent the hierarchical relationship between quality risk factors and the dynamic transmission process of risk factors,it can solve the problem that the spread of product quality risk s in complex manufacturing systems is dynamic,and its fuzzy reasoning algorithm can solve the ambiguity and uncertainty of factors affecting product quality.Therefore,this thesis used fuzzy Petri nets to establish a product quality risk evaluation model,and gave the calculation method of the risk evaluation value.Finally,this thesis taken the Z company vehicle manufacturing system as the evaluation object,combined its quality management status quo,used the established product quality risk evaluation model to calculate the risk value,and the results obtained were consistent with the actual situation of the company.It showed that the proposed product quality risk assessment model can accurately predict the system product quality risk to a certain ext ent,and had practical application significance.