自由曲面加工理论与应用(第03讲--刀具路径生成算法概述)

自由曲面加工理论与应用

第03讲--刀具路径生成算法概述

刀具路径生成方法的分类

（Taxonomy of tool-path generation）

❑刀具路径生成方法包含的要素（Tool-path generation (TPG) mechanism）

•1）刀具路径规划的区域(Path-planning domain)

在二维区域内规划走刀模式（toolpath patterns），生成刀

具路径

（2D domain where tool-path patterns are planned）

•2）刀具路径生成的曲面(Path-generation surface)

在CC-surface或CL-surface等3D surface上生成刀具路径

（3D surface →CC-surface or CL-surface）。

三种刀具路径规划的区域（Three types of Path-planning domains）

1)参数区域(Parameter-domain(PD)): tool-paths are planned on the u,v-domain of the 3D surface r(u, v), and then they are mapped back to r(u, v).

2)导动平面(Guide-plane(GP)): tool-paths are planned on a separate “guide-plane”, and then they are projected on the surface.

3)导动曲面(Drive-surface(DS)): tool-path are defines as a series of intersection curves between “drive surfaces”and the pare-surface

❑TPG-mechanism = (PD CC , GP CC , DS CC , [PD CL ] , GP CL , DS CL )PD CC ——CC-based parameter-domain method

GP CC ——CC-based Cartesian tool-path

DS CC ——CC-based APT-type tool-path

PD CL ——CL-based parameter-domain method

GP CL ——CL-based Cartesian tool-path

DS CL ——CL-based APT-type tool-path

对3轴刀具路径生成而言，CL-based method have distinct advantedges over the traditional CC-based methods.

Note the combination ‘PD CL ’is optional because it is not likely to be employed in practice.

刀具路径生成方法（Tool-Path Generation Methods）

1) Conventional TPG Methods (CC-based methods)

2) CL-based Method (C-space method)

CC-based TPG methods

种类（对应于三种刀具路径规划的区域）

(1) Isoparametric method: CC-paths are planned on the parameter-domain

(2) CC-Cartesian method: Tool-paths are planned on a guide-plane

(3) APT method: Intersecting the part surface with a series of drive-surfaces.

过程（TPG procedure in CC-based methods）：

1) Mapping: computation of a CL-point for a given ¡domain-point¡.

2) Marching: find the next domain-point from the current point on the path.

3) Side stepping: find the initial domain-point on the next path.

Isoparametric Tool-Path Generation

刀具干涉（Cutter-interference）

❑刀具干涉的种类（Cutter interference types）•曲率干涉（CL-point interference）

gouging occurs at a CL-point.

•运动干涉（CL-line interference）

gouging occurs on a CL-line.

•碰撞（collision）

Dead center collision (round-endmill), holder collision and

shank collision

1）曲率干涉（CL-point interference）

Sufficient condition for concave-gouging：d > 1/ρ　,

2）运动干涉（CL-line interference ，Convex gouge)（1）凸干涉（Convex-gouge）