Reverse Engineering Of Key Technologies Of Rapid Prototyping And Manufacturing

Rapid prototype manufacturing (RPM) is the advancement of the modern technology, so it has very important meaning for quoting reversing engineering (RE) in PRM:completed the information integration between RPM and RE,and formed a fast feedback design system including designing,manufacturing and inspecting.So with the devolepment of modern compute technology and test technology, RE using CAD/CAM technology and modern manufacture technology to complete part's prototype, has becoming a study hotpoint in CAD\CAM field,and the main content of RE technical application.In this paper, some key technologies of RE based on the point cloud data obtained from laser scanner are deeply studied and discussed, including the preprocessing of data points, the intetation of RE and RPM and the methods of surface reconstruction.This paper chiefly has finished the tasks as follows:(1) Processing of data points: The study for processing of data points in this paper is mainly concentrated capturing, classifying and preprocessing of the data point .Mainly, through deeply analyzing and studying in removement of the noisy, caculating and analyzing of data point, reduction and smoothing of cloud point data, a kind of changeable minmum distance method and a kind of fixture filtering- median filtering and weighed-median filtering are imposed in this paper. And the algorithm principle and data processing of the whole data processing process has been described by a practical example, also verified its validity.(2) The integration of RE and RPM: To the shortage of the interface file of RE and RPM—STL style, in this paper a kind of adaptive slicing method is proposed,which not only avoids the error form grid melts approximate,but doesn't need the intermediary file to converse;So tthe precision and efficiency of RPM is improved.(3) Surface reconstruction: NURBS surface reconstruction may express twice regular curve and curved surface accurately, so it can express regular curved surface and freeform curved surface using unified mathematics form,and other non-rationed method can't do this. ISO has promulgated the STEP international standard about industrial product data exchange, and looked NURBS method as only mathematics description method defined industrial product geometry shape, which makes NURBS method the most important foundation in the modelling technical development tendency of curved surface. NURBS surface reconstruction is mainly studied in this paper.(4) Software completing and example testing: Firstly, system developed for the basic requirement of computer is explanated; Later, the whole designs of software and the function of every module are illustrated;Last, the effectivity of adaptive slicing is testified in RPM by an example .