Research On The Milling Stability Of Titanium-aluminum Alloy With Weak Stiffness Surface

This paper focuses on the stability of TiAl alloy thin-walled curved surface finishing,from five-axis ball-end milling tool milling stability,milling stability algorithm,TiAl alloy thin-walled parts milling experiment,TiAl alloy thin-walled surface finishing surface quality and parameter optimization,etc.The specific research content is as follows:(1)Establish a dynamic model of the ball-end mill,and obtain the dynamic cutting force on the cutting edge according to the micro-element geometric model of the cutting edge of the ball cutter.A semi-analytical model of the contact area of the ball-end mill workpiece is established,and the accurate solution of the curve projection of the contact area boundary is obtained.The semi-discretization method is used to predict the stability of five-axis ball cutter processing.(2)An improved third-order semi-discretization method for predicting milling stability is proposed.The improved third-order semi-discretization method is compared with the low-order semi-discretization method in terms of convergence and effectiveness.The results show that the convergence rate of the third-order semi-discretization method is higher.In terms of algorithm effectiveness,the improved third-order semi-discretization method has both computational accuracy and computational efficiency.(3)Establish a dual-flexibility dynamic model,use the mechanical model method to measure the cutting force coefficient,combine the hammering test and finite element simulation,obtain the modal parameters,and verify the construction model.Carry out stability simulation to provide theoretical guidance for actual processing.(4)Carrying out the orthogonal test of finishing,through the range analysis,it is found that the primary and secondary order of the influence of each factor on the roughness is:line spacing>feed per tooth>spindle speed>axial depth of cutting.It is found through variance analysis that the line spacing p has a certain influence on the surface roughness.The spindle speed,axial depth of cut and feed per tooth have no significant influence on the surface roughness.A multi-objective optimization model was established.The final optimization results obtained using genetic algorithm are:spindle speed n=4250(rpm),axial depth of cut a_p=0.852(mm),feed per tooth fz=0.274(mm/z)and Line spacing p=0.121(mm).