自由曲面数控加工刀位轨迹与加工精度的研究

Research Into Cutter Tracks of the NC Machine on Free Curved Surfaces and Machine Precision

自由曲面数控加工刀位轨迹规划与加工精度的控制,是计算机辅助制造(CAM)必须要解决的问题。由于自由曲面加工的数控程序是由序列线性插值的刀位构成的,在确定走刀步长和切削行距时必须考虑线性逼近误差和残留高度(或过切量)。论述了立铣刀用于较小曲率曲面加工时刀位轨迹的生成方法,切削步长和立铣刀铣削时后跟角的计算方法,给出了立铣刀过切干涉检查方法,直接给出了加工微分几何结构不同的曲面时,影响加工精度的接刀刀痕高度的数学表达式,用图表达了4个给定的切削行距时,接刀刀痕高度与刀具半径的比值与铣刀倾斜角(后跟角)的关系。

The programming of reamer track machined by numerical control on the curved surface and the control of machining precision are the problems that must be solved by CAM. Because the numerical control program machined by the curved surface is made up of reamer of sequence linearity insert value, linearity which is closed to error and left high(or over- cutting measure) must be considered when the length and cutting row spacing are fixed. In this article, we describe how the reamer track produces and introduce some ways to calculate the length and angle when vertical milling cutter is used in curved surface of less curvature. At the same time we present the ways to over- cutting check, and the maths expression about reamer track high which influences machining precision when we machined curved surface of different differential coefficient geometry structure, and the relations between ratio of reamer track to radius and tilting angle of milling cutter when four cutting length with draft were given.