Research On Reverse Engineering And Numerical Control Machining Program Of Complex Part's Surface

The reverse engineering and its key technique of complex part抯 surface are researched and explored in this paper, which by the reverse engineering of electric fan vane and hear-accept mike and based on that the basic theory, research status, application field, technique of reverse engineering in the manufacture field at present are analyzed and summarized, including data measuring, and data processing, and surface reconstruction, and numerical control machining program. The mostly harvest as following: 1. Automation measuring mode and automation programming mode of three-CMM which is the common measure tool in reverse engineering are analyzed and compared. By scanning measure the surface of electric fan vane and hear-accept mike, The concreting step and method of the probe choice, and calibration of probe head length, and define probe and calibration of probe radius, and establish part measure reference frame are discussed. At the same time, the principle of choice probe radius is pointed out and a new method of establish abnormal shape part measure reference frame is put forward, using work table-board of CMM and three marked points of part boundaiy. So abnormal shape part抯 measure reference frame can be established by this method. The best measuring surface layout along creating line is explored. This layout can increase efficiency of scanning measure and decrease scanning data point. 2. The conception and theory of data processing in reverse engineering are discussed, including transforming data format and offsetting, and eliminating yawp points, and putting many data points view together, and simplifying data points , and densfying data points, and ordering data points, and clipping data points. By processing scanning data the surface of electric fan vane and hear-accept mike, a 3D boundary method that can eliminate yawp points speedily is explored. This method defines a polygon to surround the 揷loud?data that need to be eliminated; taking part 3D boundary measured as reference, so the 揷loud?data can be eliminated in the polygon. The method eliminates yawp points speedily outside 3D boundary as well as keeps the real points inside 3D boundary, and improves efficiency of eliminating yawp points. In addition, the principle of the same concave and protruding nature is put forward at the clipping loud?data. That to say, the surface has the same concave and protruding nature, and relatively flat where loud?data are clipped. At last, the author emphasizes that 揷loud? data must be ordered, this is indispensability step of surface reconstruction. ?III ? 3. The basic theory and method of surface reconstruction are discussed. The process of surface reconstruction of 揷loud?data by Cimatron software is explored. First, to create scanning lines; second to order scanning lines; third to trim surface by a plane; last to adjoin some surfaces, it is a short cut of surface reconstruction. The plane method is the best method of creating 3D scanning line by research. The method that high precision NURBS surface is reconstructed by 3D boundary is studied out. It makes surface reconstruction conveniently and quickly. The method of trimming surface by a plane first and then adjoining is put forward. Some surface can be adjoined smoothly by this method. 4.