切削力建模方法综述

航空航天工程广泛采用薄壁复杂结构零件, 实现其高效精密数控加工关键技术具有重大的现实意义. 传统的CAD/CAM软件在确定切削策略和规划刀位轨迹时, 一般仅基于零件的理想几何形状. 由于切削力引起的刀具、零件显著的加工变形即``让刀'现象, 必然导致零件的实际加工表面与理论值之间存在较大偏差. 工程师往往不得不通过选用比较保守的切削用量和多次重复精加工过程来保证零件的加工精度. 为了能够从根本上解决这一问题, 很有必要通过建立准确的切削力预报模型, 仿真切削加工的物理过程, 揭示工件和刀具的加工变形规律,补偿原始数控刀具轨迹, 最终达到改善工件加工精度和提高加工效率的目的. 本文综述了各种不同的切削力建模方法, 包括基于切屑形成机理的二维正交切削力模型、基于单位切削力系数的铣削力模型、神经网络模型以及模糊灰色理论等. 目的是为实现薄壁复杂结构零件的加工变形预测控制、关键工艺参数优化以及加工过程的物理仿真提供理论基础.

AN OVERVIEW ON CUTTING FORCE MODELING

Precision machining of thin-walled complex aeroengine components is one of the most critical re- quirements with respect to their excellent performance.Achieving the right profile for complex parts increasingly depends on the use of CAD/CAM packages for defining optimal cutting strategies and tool paths.However, most of the existing multi-axis CNC programming key techniques are based only on the idealized geometry and do not take into account factors such as cutting force induced part/tool deflections.As a result,there is usually a significant deviation between the planned and machined part profiles.In order to avoid these undesirable results,such as over-cut or under-cut,production-planning engineers are conservative in the selections of pro- cess parameters.In this paper,different approaches of cutting force modeling are discussed,which include chip formation or tool-chip interface friction based analytic force model for orthogonal cutting,milling force model based on the cutting coefficients,artificial neural networks,and fuzzy-grey theory.The key is to predict the workpiece/tool deformation,optimize the key process parameters,compensate the tool paths,and realize the physical simulation of machining process.