Research On 5-axis NC Machining Theory And Technology Of Shoe Last

In this thesis, in the background of shoe last NC program, the shoe last surface modeling, CNC machining programs, and shoe last five-axis NC machining programming are studied.Mainly includs calculation of NC tool cutting contacts, cutter location data calculated, the post-processing and other key technologies.And last,demonstrate the proposed relevant methods and theories using CNC machine simulation. Major contents of study include:1.The shoe last surface modeling and shoe last NC program is given. Firstly, reconstruct shoe last surface throng ImageWare,extract the data from the resulting IGES file, preparate non-uniform B-spline surface method procedure, andthen build the shoe last surface model in MATLAB. Based on the surface model and five-axis NC machine work principle, determine the spiraling processing methods, and give Construction method of the spiral and the guide lines.2.Based on the NC machining program of shoe last, a calculation method of the cutting contact point is proposed. There are three main priorities:a) for the shortcomings of the existing intersection method, a simple and efficient algorithm of curve and line iterative projection algorithm is proposed, and then obtain the initial point of search method using the algorithm; b) under the spiral processing features, a new second-order search algorithm is given, and get all the cutting contact points.The algorithm greatly improves the efficiency and precision, stability and reliability, and reduces the sensitivity of the initial point; c)Because shoe last surface is formed by three surfaces, surface discrimination method is given by combining with surface junction.3. The calculation method for cutter location point and tool axis vector is given. Depending on the selection tool(end-ball tool), calculate the cutter location point, and fitting tool path curve through the B-spline curve method. Combined tool characteristics and processing methods, the method of calculating tool axis vector is given, using cutter location point and tangent vector of feed direction.4. Post-processing for dual table 5-axis NC machine is given. Carry on the shoe last NC machine simulation in VERICUT.The NC program and theories and methods which relevant to the thesis have been proved available.