Adaptation of feed rate for 3-axis CNC high-speed machining

ZHANG De-li, ZHOU Lai-shui

College of Mechanical and Electrical Engineering,Nanjing University of Aeronautic and Astronautic,Nanjing 210016,China



Abstract:

To improve the efficiency of CNC machining,assumptive transit circular arc is used to contour two adjacent moves together on the corner to make smooth paths. The radius of transit circular arc can be adjusted with contour accuracy,and the feed rate on the corner can be controlled through limiting the maximum feed rate of transit circular arc segment. A look-ahead algorithm for a series of moves is proposed for speed adjustment in advance,which avoids the occurrence of overload of cutting tool on the corner and reduces the servo track error of parts on the corner or of circular arc move. Equivalent trapezoidal velocity profile is used to analyze the speed of S-curve velocity profile and work out its accurate interpolation,which overcomes the disadvantage of looking up table to calculate feed rate approximately,hence high accuracy and fine surface quality can be obtained while the machining speed is high. The proposed methods can meet the requirements of real-time analysis of high-speed machining. The presented algorithm is effective and has been adopted by CNC system of newly developed high-speed milling machine.

Key words:  CNC  feedrate smoothing  S-curve velocity profile  high-speed machining

DOI：10.11916/j.issn.1005-9113.2009.03.018

Clc Number:TG659

Fund: