基于空间限定法的曲面五轴加工刀-工接触几何分析

Contact Geometry Analysis of Workpiece and Cutter for Five-axis Curved Surface Machining Based on Space Limitation Method

曲面五轴加工中刀-工空间位置变化复杂,针对不同的工件,选择不同刀具的多变加工参数和复杂的加工条件,使刀-工接触几何分析建模成为难点。基于微分离散思想,沿刀具轨迹将曲面五轴加工离散为一系列刀位点处的斜平面五轴加工。以斜平面五轴加工为研究对象,基于解析法将刀-工处于接合状态下的各特征曲面表征为数学解析式,分析各特征几何曲面与加工时刀-工的特点,从空间几何的角度构建刀刃参与切削的限定条件,从而实现对刀刃接触区间的提取。相比于传统的解析法,空间限定法的结构更简洁,可实现性更高,不依赖刀-工接触区域。与实体法相比,空间限定法在斜平面加工仿真中具有相同精度且计算效率更高,在曲面仿真中存在可接受的轻微精度损失。

In the five-axis machining of curved surfaces,the spatial position of the tool axis and the workpiece changes complicatedly.Since the choice of tools for different workpieces is different and the processing parameters are also variable,the complexity of the processing conditions makes it difficult for the the contact geometry analysis.Based on the thinking of differential discretization,the five-axis machining of the curved surface is discreted into five-axis machining of the inclined plane at each tool point along the tool path.Taking the five-axis inclined plane machining as the research object,each feature surface of the tool and the workpiece in process is represented as a mathematical formula,and the characteristics of the tool and the workpiece each geometric feature surface during processing are analyzed.Then,from the perspective of space geometry,the limiting conditions for judging the cutting edge to participate in cutting are constructed,and the in-cut cutting edge(ICCE)is obtained.Compared with the traditional analytical method,the space limitation method has a simpler structure and higher achievability,and does not depend on the cutter workpiece engagement(CWE).Compared with the solid method,the space limitation method has a higher calculation efficiency while ensuring accuracy in the oblique plane machining simulation.The method has a slight loss of accuracy in curved surface simulation,but it is acceptable for cutting force and dynamic modeling.