Research On Tool Path Planning Of Ultrasonic Assisted Magnetic Abrasive Finishing Of Titanium Alloy Blade

The working performance and service life of titanium alloy integral impeller is directly affected with its quality.It is difficult to meet high quality and efficient finishing requirements of the titanium alloy integral impeller by traditional machining methods,so ultrasonic assisted magnetic abrasive finishing which is one of multiple composite finishing technologies is considered as a critical technique for solving this problem.And it is important for integral impeller to generate tool path planning,which will directly affect the finishing quality and efficiency of it.Therefore,research on tool path planning of ultrasonic assisted magnetic abrasive finishing of titanium alloy integral impeller blade is carried out for the problem of titanium alloy integral impeller of finishing.The main work and conclusions as follow:(1)Curve equation of titanium alloy integral impeller blade is established by interpolating discrete points on the blade curve according to cubic B-spline interpolation theory.Smoothness of the blade curve is detected by analyzing parameters of discrete points on it.And the blade curve is smoothed based on the theory of local energy minimum value.Equation in the form of ruled surface of the blade is obtained by offsetting the discrete points on the blade curve.Solid model of the integral impeller blade is constructed.(2)Approximate equivalent discrete model of the ruled blade surface is established by analyzing the characteristics of the titanium alloy integral impeller blade.Material removal pits of ultrasonic assisted magnetic abrasive finishing are obtained by single point finishing experiments on titanium alloy workpieces under different finishing parameters using hybrid orthogonal design.Material removal curves of the material removal pit in different planes are fitted according to the maximum likelihood estimation method and the least squares method.Material removal function is established based on quadratic polynomial stepwise regression method.And the material removal function is tested by experiment.The results show that the fitting accuracy is relatively accurate.(3)Adaptive model of feed rate for curved ultrasonic assisted magnetic abrasive finishing is proposed by analyzing process of material removal.Based on adaptive model of feed rate,model of step length planning is established.And model of path interval planning is established by constructing superposition model of material removal depth curves of contact area between the corresponding tool contacts on adjacent tool paths.The path planning is tested by experiment.Maximum errors of experiments for the adaptive model of feed rate and the model of path interval planning are 1.3%and 4.4%,respectively.(4)Initial path is determined for the titanium alloy blade.Models of tool axis vector planning and tool point coordinate calculation are derived based on spatial contact model between tool and blade surface.According to tool path planning theory of ultrasonic assisted magnetic abrasive finishing of titanium alloy integral impeller blade,the finishing of blade is simulated under the condition that theoretical finishing error of step direction is 0.2?m and 0.1?m,and theoretical finishing error of path interval direction is 0.5?m and 0.2?m respectively.The results show that the maximum finishing error of the step direction is 0.195?m and 0.096?m,and the maximum finishing error of the path interval direction is 0.5?m and 0.2?m respectively.The results meet finishing requirements.And correctness of tool path planning theory is verified.