Research & Application On Decision-Making Of Machining Method Based On Fuzzy Reasoning

As the requirements of the agility and parallelization manufacturing are getting higher,3-D Computer Aided Process Planning System(CAPP) is paid much more attentions increasingly.While the transformation from 2-D to 3-D,new problem occurred in the process generation of CAPP sysytem,that is,the decision-making of manufacturing methods is difficult due to the innumerable information of the 3-D products.The decision-making of manufacturing methods is to determine the manufacturing method and the concrete manufacturing stage of the features on the part.The procedure of decision-making is complicated due to the comprehensive effects of the precision requirement,the experience and knowledge of process maker,and the equipments and all these subjective factors lead to the fuzziness of the decision-making.In this thesis,by using the fuzzy mathematics theory,the complicated part manufacturing decision-making problem is solved.First,the common used features of the complicated box part are analysed and the new concept of manufacturing feature which oriented to the CAPP application field is proposed according the link-lack between the geometric information and manufacturing information in CAM system of the product 3-D model.This concept brings more convenience to the integration between CAD ans CAM system.The fuzzy decision-making is devided into three steps and every step's modeling is discussed in this thesis and the forward-direction hybrid fuzzy reasoning method is applied on the manufacturing method decision-making module.Second,the fuzzy map between manufacturing feature and typical manufacturing method in knowledge base is built.According to the normal distribution,the membership functions of the factors which have influences on the manufacturing methods decision-making are constructed.The reasoning results are selected according to the maximum membership grade method.Because the reasoning procedure is multi-factor,multi-objective,so the layered comprehensive evaluation method is expounded and took the two layers as an example.Last,the system is testified by a box part and the reasoning results are compared and analysed.