Research On New Method Of Detecting The Surface Flaw Of One Kind Of Workpiece And Realization Of The System

At present, the study of error separation theory and its application technique are at the stage of further research and consummation. Meanwhile, the NDC using eddy current is rising and developing. And both of them are studied in these two fields of roundness measurement and NDT respectively. In this subject, a new method and technique that applied the error separation theory to test of the surface flaw of axis-like parts using eddy current is proposed for the first time. Based on this method, a mathematical model of extracting the surface flaw of axis-like parts is established. Then "An automation system for the eddy current examination of the surface flaw of axletree" is designed. The system can test the information of work piece's Length-fault, Diameter-fault, Shape-fault and Surface-flaw fault simultaneously and use various appraising algorithms to test the results. Thus the problem of NDC of the work piece's Surface-flaw has been solved. The system and its appraising algorithms have been proved correct and feasible by experiments.The paper introduces the principle of testing, designs of hardware and software and corresponding appraising algorithms respectively. First, the research necessity and the practical value of the subject are discussed in the paper. Second, based on the theory of error separation, the mathematical model, which is used to extract the surface flaw of axis-like parts, is given briefly. Third, the designs of hardware and software in the system are explained respectively. Fourth, the models and algorithms for appraising the surface flaw of axis-like parts are established by the methods of pattern recognition and neural net. The comparison is made among the various methods. At last, the deficiencies and certain aspects to be improved in the system are given in the paper.