Research On CAPP System Of Sheet Metal Based On Ontology

As a part of the manufacturing industry,sheet metal industry is widely used in real life.The processing technology of sheet metal parts as a key link connecting product design and processing has become particularly important,but the vast majority of enterprise process designers have the problems of low design efficiency and poor design quality,especially the storage,reuse and sharing of process data is difficult to meet the actual needs of enterprises.In the process of sheet metal part process planning,there are a large part of sheet metal parts with similar process flow,which can be directly modified and reused.Therefore,this paper proposes the research of sheet metal CAPP system based on ontology,constructs the ontology model of sheet metal part process knowledge,and realizes the representation of sheet metal part process knowledge.Based on this,the ontology database of sheet metal part process knowledge is formed,and the sheet metal CAPP system is developed to realize the sharing and reuse of sheet metal part process knowledge.The research process is divided into three parts:Firstly,the process knowledge of sheet metal parts is defined and classified by analyzing the characteristics of sheet metal parts.The process design knowledge of sheet metal parts is divided into three parts: type knowledge of sheet metal parts,feature information knowledge of sheet metal parts and processing technology knowledge of sheet metal parts by using knowledge classification method based on design process.Combining the advantages of seven step method and skeleton method,the process knowledge of sheet metal parts is modeled.According to the classification of process knowledge of sheet metal parts,ontology editing tool protégé is used to construct the ontology model of sheet metal part process knowledge,and the knowledge representation of a specific product example of an electrical equipment manufacturing enterprise is realized based on OWL.The ontology model of sheet metal part process knowledge is analyzed by using Jena,and the ontology is stored in owl document and imported into relational database to form the ontology database of sheet metal part process knowledge.Then,through the research and analysis of the constructed ontology database of sheet metal parts process knowledge,the research method of retrieving similar process documents in ontology database by using ontology mapping similarity algorithm is proposed,and the specific algorithm model is constructed.By selecting five sheet metal parts to form four groups for ontology instance similarity comparison,the analysis and comparison results verify the effectiveness and feasibility of the algorithm.It can effectively retrieve several sheet metal part process documents with high similarity index for selection,and reuse the existing process documents through simple modification.Finally,web technology is used to develop sheet metal CAPP system based on B/S architecture.The interactive interface is applied to HTML and Javascript technology,and My SQL is selected as the database.It realizes the query of sheet metal parts,process analogy and copy,storage and search and management of process files,which is convenient for other technologists and managers to share and reuse process knowledge.