Topography Simulation And Parameters Optimization For Fly-cutting

With the widespread application of free-form optics in optoelectronic products and communications products, such as digital camera lens, night vision device lens, optical printer lens, Optical Fiber Coupler, reflector and lamp shade of lighting lamp and light guide plate of displayer. People pay more and more attentions to manufacturing of free-form optics. Ultra-precision fly-cutting can directly get optical elements which have nanoscale surface roughness and micron-sized surface precision, especially for optical elements which cannot be manufactured by polishing, fly-cutting is the only way of processing. Prediction of three-dimensional surface topography can provide references for controlling process quality and parameter optimization. Because of the complexity of the curved surface machining, there is no ready-made manual can choose the appropriate processing parameters. According to the experience to select the processing parameters, may be cannot meet the processing requirements. So it is necessary to carry on the processing parameter optimization for fly-cutting.By analyzing the topography of plane, an approximate description for swept volume of cutters was established. According to the change in the curvature of work piece, dimensional gridding of the work piece was finished. Analyzed the height of one point was not only decided by an adjacent tool path, the criterion for getting the tool paths which influenced the height of cloud points is presented. Comparing the point height between the pieces and tool swept volume, choose the smaller one as the finally height of the current point. According to the space transformation, a local-coordinate system was built.By analyzing the factors of affect surface finish of work piece which is manufactured by ultra-precision fly-cutting, optimization parameters are determined, including spindle speed, federate depth of cut and step distances. Established the mathematical model of optimization parameters, which regard machine time as the goal. Binary encoding of optimization variables, using the method of random generating initial population, selection, crossover and mutation operation, get the optimized processing parameters.Comparing the topography between reality and simulation, the results demonstrate the effectiveness of this algorithm. Through varying the spindle speed, federate, depth of cut and step distances, topography of simulation are got. Based on topography, analyzing the influence of parameters to surface quality. Comparing the machine time and surface roughness between after parameters optimization and before parameters optimization, the results proved the effective of algorithm.