Research And Application Of The Method Of Smoothing Transfer Of Inter-trajectory For High-speed And High-accuracy Machining

With the development of modern CNC technology, high-speed and high-accuracy machining has become a new trend. While the transfer speed of inter-trajectory influences the efficiency and accuracy of machine seriously, when the corner angle of inter-trajectory is bigger, larger changes in speed at the corner will cause greater impact on the machine. So realizing the smoothing transfer of speed of inter-trajectory and reducing the impact of machine caused by sudden change of speed at corner is a key factor to improve the efficiency and accuracy of machining.At present, the studies of speed smoothing of inter-trajectory for NC system are mostly limited to non-turning point of the adjacent trajectory segment and based on simple trapezoidal accelection and decelection, which have the shortcoming of frequent stops of motor, lower efficiency, not-smoothing surface and etc. For the drawbacks of above-mentioned method, in order to realize the speed smoothing of inter-trajectory and satisfy the need of high-speed and high-accuracy of CNC, and considering that the contour of a special part commonly consists of common surface (non-micro segments) as well as the complicated surfaces (micro segments), this paper has mainly studied the speed smoothing method for non-micro segments and micro segments respectively.Firstly, the architecture of Lantian NC Platform and design scheme of related motion plan were introduced.Secondly, the principle of vector transfer method for speed smoothing of non-micro segments was discussed. The method was based on the s-curve and had achieved the speed smoothing by planning the adjacent segments at the same time.Thirdly, the principle of dynamic transfer planning method for micro segments was discussed. The method had achieved the speed smoothing by forming multiple segments into machining chain, and then solving the transfer speed of the machining chains.Finally, the application on the Lantian NC Platform of the two methods was given. For different trajectories, a large number of tests were carried out and the results were analyzed.The methods designed are simple, reliable, and able to achieve smooth and high-speed transfer of inter-trajectory, so can meet the requirement of modern CNC system for high-efficiency and high-accuracy.