Research On Process Planning And Program Generation Technology For Key Parts Of Marine Diesel Engine

The structure of marine diesel engine parts is complex and the machining precision of parts is high.When measuring a component with a CMM(Coordinate Measuring Machine),because of there are many items to check,manual information collection,manual sampling in parts,the need for experienced staff to the overall measurement of parts of the path planning,these factors led to the marine diesel engine key components on the CMM for a long time and low efficiency.This situation has become a bottleneck restricting the development of CMM inspection technology for marine diesel engine parts.Aiming at the above problems,this paper made a careful study of marine diesel key components in CMM inspection process,the model definition based on(MBD,Model Based Definition)computer aided inspection planning technology of CMM is studied.The research contents are as follows:In order to get through the transmission chain of design and inspecting process,the extraction method of inspecting information in MBD model was studied.According to the characteristics of different types of information,different information extraction processes are proposed to extract the inspection information quickly and accurately.It provides the data base for the integration of CAD / CMM and the planning of the follow-up inspecting path.According to the method of establishing the coordinate system,the rules of determining the number of sampling points and the position of the element,and the principle and experience of the detection process planning,the sampling rules of the common inspection elements of the marine diesel engine key components were established,and the internal sampling points and distribution of the elements were standardizedAccording to the working characteristics of the three coordinate measuring machine,the factors that affect the path of the stylus when measuring the parts were concluded.Based on the constrained model and the inspecting path planning rules,the genetic algorithm was used to optimize the inspecting path by using the polychromatic sets theory to establish the constraint model of the CMM inspecting.Finally,the CMM automatic inspecting software system of marine diesel engine key components was developed in the NX/Open API secondary development environment by VC ++ programming language,and the function of the software was verified by the example of cylinder block inspection.With this system,the extraction of inspecting information of marine diesel engine key components can be realized,the planning of the inspecting path was detected and the DMIS program was automatically generated,and the generated DMIS program was virtualized in the NX / inspection module.The system can effectively improve the inspecting efficiency,with important engineering application value.