Development Of Smooth Motion Trajectory Planning And Simulation System For NC Machining

High-speed and high-precision processing requirements of complex surface CNC machining technology has become an important symbol to measure the processing capacity of modern CNC system in the 21st century, parts of the complex surface is also widely used in mold manufacturing, car, aerospace, shipbuilding, mold manufacturing and other industrial manufacturing fields. For a long time, complex surface NC machining tool path planning, trajectory optimization, interference and collision processing, dynamic simulation of the cutting process and the like, have been restricting the development of high-speed CNC machining technology.The paper based on analysis of the advantages and disadvantages of various CNC tooling track in recent years, proposing and defining a new spline curve called adjustable triangle-shaped cubic spline interpolation curve to realize the unified representation of straight line, common quadratic curbe and free curve, and using the interpolation spline for a unified description and smoothed processing of the tool path; the paper proposed a interpolation algorithm called "pulse incremental interpolation based on tangential direction and continuous interpolation between spline curve" which is based on pulse increments interpolation of this cubic spline curve, and realized a rapid direct interpolation and continuous interpolation of the spline effectively, so as to enable the tool path to achieve a microscopic smoothness and enhance the microscopic smoothness of surface machining.According to the complex surface NC machining tool path planning, the paper put forward a kind of "three-dimensional spiral" tool smooth motion path for high-speed high precision machining. Using Cubic Trigonometric Cardinal Spline to interpolate intensive discrete cutter location data points obtained by certain path planning algorithm, then obtaining a smooth continuous three-dimensional spiral tool path, which can effectively reduce acceleration and deceleration, pausing and direction changing during tool processing, in order to achieve a smooth and continuous tool motion, so as to reduce shock and vibration of machine tool system, improving the macro smoothness of the surface processing.Based on the above trajectory planning algorithms, the paper combined Visual Basic with Access database to create the corresponding automatic programming software about three-dimensional spiral tool path to achieve integration process from model data processing to the NC program, and achieved the three-dimensional simulation of rough cutting process which is on the basis of AutoCAD 3D cutting motion state simulation, and then used SolidWorks and VERICUT to create a virtual CNC milling machine, then imported the resulting NC program for simulation of CNC machining process, which verify the correctness of the NC program and detect interference situation in the process, and at last compared simulation results to Mstercam contour layered milling path results aim to verify the smoothness and rationality of three-dimensional spiral tool trajectory presented by the paper, then applied different tool path planning algorithms to the actual experiment processing with CNC milling machines, and compared experimental results to prove that the three-dimensional spiral tool path presented by the paper with good usability and superiority can meet NC machining requirements of the actual free-form surface.