Block processing time-based programming for high-speed, high-precision 5-axis machining

• Published in: Precision engineering 2024-06, Vol.88, p.497-515
• Main Authors: Otsuki, Toshiaki, Sasahara, Hiroyuki
• Format: Article
• Language: English
• Subjects: 5-Axis machining; Block length; Block processing time; High-speed high-precision machining; Programming; Tool center point control
• ISSN: 0141-6359; 1873-2372
• DOI: 10.1016/j.precisioneng.2024.02.014

For high-speed and high-precision machining with orthogonal 3-axis minute line segment commands, a program should be generated by appropriately reducing the chord error (tolerance) or the block length (line segment length) based on the computer numerical control (CNC) block processing time Tb. The block processing time Tb is the duration from when the CNC decodes one block command in a program until when it controls the motors, depending on the processing power of the CNC. Accordingly, even in simultaneous 5-axis machining, it is necessary to research whether programs generated based on Tb can achieve high-speed and high-precision machining. Therefore, this study aims to realize simultaneous 5-axis machining at higher speed and precision using CNC programs with minute line segment commands based on Tb. In addition, we propose a more general identification method compared with that used in previous studies to identify Tb. Simultaneous 5-axis programs include two cases of control, namely, tool center point (TCP) control and Non-TCP control, and Tb was identified for both controls. For the machining method, using the block length based on Tb, we generated programs to machine the upper flat surface of a workpiece using simultaneous 5-axis machining while rotating the two rotary axes using a ball-end mill. We machined the workpiece and evaluated the machining speed and precision of the machined surface. We showed that simultaneous 5-axis machining with higher speed and precision can be achieved using programs based on Tb. In addition, we analyzed and considered the reasons for the higher-speed and higher-precision machining. Case (TA) is the result of simultaneous 5-axis machining performed using the program with a block length based on the block processing time (Tb), which is the method proposed in this study; conversely, case (TB) is the result of simultaneous 5-axis machining performed by the program using the conventional method (linearization). Higher-speed and higher-precision 5-axis machining is observed in case (TA) than in case (TB). [Display omitted] •A novel method for obtaining the block processing time Tb of CNC is proposed.•Programs generated based on Tb enable high-speed and precision 5-axis machining.•High-speed and precision 5-axis machining is possible in TCP and Non-TCP controls.•The reasons for high speed and precision of 5-axis machining are analyzed.•A new method for evaluating the precision of 5-axis machining is proposed.