自由曲面的 CNC 直接插补加工技术

Technology of CNC Direct Machining for Free Form Surfaces

在ＣＮＣ系统上直接根据曲面几何定义与加工工艺参数对多轴曲面加工的连续运动轨迹进行实时插补控制，在ＣＮＣ上直接使用类ＡＰＴ高级语言编程，极大地简化了零件程序，并可在线修改与补偿机床运动结构、刀具形状尺寸及加工余量等工艺参数，使曲面精加工经济而高效。在单ＣＰＵ硬件环境下实现了从一般二次曲线到复杂的参数组合曲面，从两轴加工到复杂的五轴联动加工功能，可采用多种加工刀具与加工方式，可实时检测与处理刀具干涉，并具有合理的走刀行距与有效的进给速度控制等方面的能力。

The idea that interpolating and controlling the continuous movement for machining free form surfaces directly according to the surfaces geometry and machining parameters in CNC system is presented in this paper. With this method, high level language similar to APT can be directly used in CNC systems, thus the part program for surface machining can be greatly simplified. The kinematic structures of machine tools and the machining conditions such as cutter parameters, machining allowance,etc., can also be modified and compensated on line. As a result, surface finishing can be completed economically and efficiently. On the developed prototype system with only single CPU, the following machining capabilities have been obtained: a.quadric curves machining to parametric compound surfaces machining. b. two to five axis machining. c.commonly adopted machining cutters and schemes. d. real time detection and avoidance of cutter interference. e. rational determination of path interval and efficient feedrate control. In this paper, the principles of surface direct interpolation, its key techniques and major results are introduced.