Research On Reverse Engineering Of Complex Surface Facing To Numerical Control

Reverse Engineering (RE) refers to the process of acquiring the original technical information of the product without any technical data. In this thesis, basic theory, key technique, present research and applying status of RE in manufacture field are comprehensively summarized and analyzed, on the basis of which the whole process and key technique of complex surface's RE are researched, including data measuring, data processing, surface reconstruction and numerical control machining, taking the telephone hand-receiver as example. Main work is as following:The digitized measuring methods and devices that are generally used at present are analyzed and compared. Among them, the mechanical structure, the configuration of hardware and software, the specification parameter and the environmental request of LK G90CS15.10.8 thiee-CMM mat are used in this thesis are introduced specially. By using LK G90CS15.10.8 three-CMM, the measuring data of the telephone hand-receiver are acquired.The types and the processing methods of measured data are discussed. Aiming at the error points in points data, a method using Coons surface is put forward. Filtration is commonly used in data smoothing, and median method is adopted in this article. Moreover, the chord method and the curvature method are used here to compress the data and extract the feature points of the telephone hand-receiver measured data.The developing process of surface molding is introduced and the formation algorithm of free-form surfaces is compared By using NURBS algorithm in mis article, the telephone hand-receiver surface is reconstructed. In addition, the surface of the telephone hand-receiver is cut according to the feature curve created by the feature points.The craft of numerical control machining program of complex surface is analyzed and compared. These craft are machining method, cutting dosage, machining remainder, cuter walking mode, the cuter advance, the retreat mode, programming zero, and machiningcoordinate so on. The conclusion that the layer cutting is fitter for rough machining is made. The formula of scallop-height method controlling machining step is deduced. Finally, the cutting and cutter parameter for rough machining and finish machining of complex surface is put forward in the MasterCAM software, according to which the cutter route for rough machining and finish machining are produced respectively.