| In five-axis CNC machining,high quality tool path can make the processing process smooth and stable,which is conducive to improve the processing quality and accuracy,and reasonable speed planning of tool path can make the NUMERICAL control system has higher flexibility,can ensure the smooth increase and deceleration in the processing process,improve the processing quality and efficiency.Precision impeller machining is a typical representative of the development of five-axis CNC machining technology,which embodies the characteristics of high-speed and high-precision five-axis CNC machining technology.This paper takes runoff integral impeller parts with chassis as the research object and aims to improve the machining quality and efficiency of the impeller parts.The interpolation algorithm of tool path,feed velocity planning and nonlinear error compensation in five-axis machining are studied in this paper.The specific research contents are as follows:(1)For five axis NC machine tools in the impeller blade machining initial tool path data points more problem,put forward an improved Wright criterion based on the curvature estimation method and data compression method,first by the traditional B spline fitting method to get the initial fitting curve,and then according to the proposed method logarithmic stronghold for the first and the second filter,and then to simulate global fairing logarithmic stronghold,finally,the tool path simulation is carried out and the fitting accuracy is compared with the local smoothing,which proves the correctness of the global smoothing and the effectiveness of the proposed algorithm.(2)On the characteristics of traditional speed of rotation and translation can’t coordinated movement of the shaft,trapezoidal deceleration control method is presented in this paper,on the basis of targeted solutions are put forward: with the axis of rotation angular velocity and angular acceleration to limit the largest translational axis feed speed and acceleration,and get a more reasonable rotation of the maximum angular velocity and angular acceleration.To achieve this: Firstly,the cycle number of each stage of the trapezoidal acceleration and deceleration model is planned,and then the speed in each cycle is calculated.The residual speed is evenly distributed in the deceleration period,and finally the tool is driven to the end point of the machining section accurately.The five-axis coordinated and smooth motion can be realized,which can reduce the vibration of the machine tool and improve the machining quality.(3)In this paper,the A-C five-axis CNC machine tool with double turntable is taken as the research object,and the nonlinear error caused by the control of two rotating axes by linear interpolation method is analyzed and the mathematical model is established.By analyzing the movement transformation of the machine tool,the mathematical expression of the actual position of the tool point and its inverse formula are deduced.This paper proposes a compensation method for inverse interpolation position of rotating center based on known theoretical tool point,which makes the maximum limit of actual tool point coincide with theoretical interpolation path.MATLAB simulation results show that nonlinear error is significantly reduced after compensation,which can meet the machining requirements.(4)Based on MATLAB/GUI platform,developed a processing code results visualization software,users can intuitively and truly observe the simulation results through the software,has the characteristics of simple operation,convenient to use. |
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