Stability Analysis And Process Parameter Optimization Of Complex Surface Mould Milling

With the rapid development of modern industry and fiercer competition of market,new products with complex shapes are developed to meet the customers’ requirements in the mold field.Commonly,these products have complex curved surface.In the milling process,the variable curvature will make the actual milling parameters deviate from the nominal parameters.Aiming at the problems mentioned above in the milling process of ball-end milling cutter for complex curved surface,cutting thickness,cut-in and cut-out angle of milling process of cavity curve are corrected,the cutting thickness,tool-workpiece contact area,stability prediction and process parameters optimization of ball-end milling cutter are studied in this paper.The main contents include:In view of the milling process of cavity curve,the actual feed per tooth,undeformed cutting thickness,actual radial cutting depth and cut-in and cut-out angle are corrected through theoretical analysis,and the position of curvature mutation is analyzed;the dynamic model is established to obtain stable lobe for milling,and the influence of process parameters and geometric parameters of milling cutter on milling stability is analyzed.Aiming at the milling process of complex curved surface,by theoretical analysis method,considering the influence of surface characteristics on the undeformed cutting thickness,according to the geometrical shape of ball-end milling cutter and the three-dimensional hypocycloid model,the actual motion trajectory of the cutter teeth is obtained;according to the actual motion trajectory,considering the influence of surface characteristics on the undeformed cutting thickness,the undeformed cutting thickness is repaired.The influence of surface characteristics on the thickness of undeformed chips is also analyzed.In view of the complex surface machining process,this paper modifies the dynamic cutting thickness,establishes a milling dynamic model with variable time-delay parameters,solves the model by full discrete method,and analyses the influence of work piece curvature and forward tilt angle on the milling stability region,and verifies it by experiments.Taking material removal rate and surface roughness as objective functions,and then getting the comprehensive objective function of them.Based on stability and process parameters as constraints,the multi-objective optimization problem is established by using MATLAB,and the objective function is solved by genetic algorithm,experiments were carried out to verify the results.