Research On The Numerical Simulation And Process Test Of Slow Tool Servo Turning For Complex Surface

Slow tool servo(STS)is one kind of new turning processing technology with high accuracy and high efficiency which used to manufacture complex surface.Nowadays,some precision complex surfaces fabricated with STS have been used industrially in many advanced countries.However,the research on STS turning of complex surface technology is at start in our country,especially in Chinese mainland.Based on the self-developed STS machine tool in the lab,research on the numerical simulation and process tests of STS were taken.Firstly,the basic theory and research statues of STS was introduced.According to the character of STS turning for complex surface machining,DEFORM-3D software was secondary developed.Based on Lagrange piecewise linear interpolation,motion control subroutine was written by Fortran language,and by the means of reading cutter location points of different complex surface,the process of STS turning was simulated successfully.Secondly,surface roughness prediction model was established with the secondary developed software.Johnson-Cook(JC)material model,Coulomb friction model and adaptive meshing method were used in the finite modeling.According to the micromechanism of roughness,the parameter of displacement was used to predict the value of surface roughness and the influence of different turning parameters to surface roughness was discussed.Certainly,the effectiveness of the model was proved by verification test.And,the predictions also provided a foundation for the experiment design in the next section.Then,for improving the surface quality and getting more reasonable parameters,a optimization model of process parameters was established.To construct the multiple quadratic regression math model,process tests were designed in terms of Response Surface Methodology(RSM)and the prediction results above.With the optimized model,interaction and perturbation of the factors to surface roughness were analyzed.Desirability function approach was used to solve the multiple regression model,and the optimum parameters(i.e.tool nose radius of 0.88mm,feed rate of 5μm/r,depth of cut of 5μm,spindle speed of 200r/min and discretization angle of 2°)were determined.Comparing withthe unoptimized results,machining quality was obviously improved which proved the practicability of the model.Finally,the mathematical models of spherical surface and progressive addition surface were established,and the process tests of these two kind of surface were carried out to further verify the theory and the model above.