Study On Tool Life And Parameters Optimization Of Milling Cr12MoV Hardened Steel

This thesis aims at studying the problems of the low tool life in milling Cr12 Mo V hardened Steel in K unshan Hongli Precision Hardware Co.,. The tool life model was established by the orthogonal test of tool life in milling Cr12 Mo V hardened steel with non-coated carbide end which diameter is 10 mm, and according to the tool life model to set up the multi-objective optimization model with processing time and processing costs, using genetic algorithm for optimization of milling parameters to provide theoretical guidance for enterprise end milling of hardened Cr12 Mo V steel surface. The main contents and conclusions of this thesis are as follows:1. The range of orthogonal tests show that the feed per tooth has the largest influence on tool life, and then is the milling depth, and then is the milling speed,and milling width has the smallest influence. The optimal milling parameters is v=70m/min, fz=0.002mm/z, ap=0.4mm, ae=6mm.2. The variance analysis of orthogonal tests show that the per tooth has the largest impact on tool life, and then is the milling depth, and then is the milling speed,and milling width has the smallest impact. The optimal milling parameters is v=70m/min,fz=0.002mm/z,ap=0.4mm,ae=6mm. The conclusion of The range analysis is reliable by analysis on variance.3. The tool life predictive model T=0.1254v-0.8696 fz-1.5707ap-1.8009ae-0.0819 is established by multiple linear regression analysis, and proved to believable by analysis on variance. The Comparisons of the tool life measured value and theoretical model predictive shows that the maximum error is 12.08%, the minimum error is 0.31%, the average error is 3.61%,so the established model is highly significant with high confidence.4. The tool dominant wear morphologies and breakage form were examined by image measuring instrument, the dominant wear morphologies is rank face wear and flank wear and the dominant breakage form is chipping.5. Taking step surface of Cr12 Mo V hardened steel as the research object,based on the targets of manufacturing time, manufacturing cost, tool life optimization model, according to research of the high, constraints of milling speed, feed per tooth, milling depth milling width, setting up multi-objective optimization model of weighted coefficient, system. Using genetic algorithm toolbox of MATLAB to optimize the milling parameters, the results shows that: take manufacturing time and manufacturing cost as optimization goal, the shortening of the time and the reduction of cost is at the cost of reduction of tool life, take tool life as the optimization goal has not economic significance to the enterprise; and optimize the multi-objectives, the tool life improved nearly doubled, processing time is reduced by 1.10% and the processing cost is reduced by 6.98%, which shows that milling parameters after optimization can solve the real problem,shorten the processing time, reduce the processing cost, the optimal milling parameter is v=99.910m/min, fz=0.002mm/z, ap=0.400 mm, ae=6.018 mm.