### 通道曲面的柱面逼近方法及其在叶轮插铣中的应用

1. 大连理工大学 机械工程学院, 辽宁 大连 116024
• 收稿日期:2013-09-09 修回日期:2013-10-17 出版日期:2014-08-25 发布日期:2013-10-24
• 通讯作者: 曹利新，Tel.：0411-84708411，E-mail：caosm@dlut.edu.cn E-mail:caosm@dlut.edu.cn
• 作者简介:董雷男，博士研究生。主要研究方向：CAD/CAM、曲面多轴数控加工理论。Tel：0411-84706562，E-mail：donglei2003599@126.com；曹利新男，博士，教授，博士生导师。主要研究方向：精密复杂曲面的设计与制造、机械设计与制造中的几何学方法、曲面多轴数控加工理论。Tel：0411-84708411，E-mail：caosm@dlut.edu.cn
• 基金资助:

国家自然科学基金（51175065）

### Approximation Method of Tunnel Surfaces with General Cylindrical Surfaces and Its Application in Plunge Milling of Impellers

DONG Lei, CAO Lixin

1. School of Mechanical Engineering, Dalian University of Technology, Dalian 116024, China
• Received:2013-09-09 Revised:2013-10-17 Online:2014-08-25 Published:2013-10-24

Abstract:

In order to make the machined tunnel surface of an impeller as close as possible to its designed surface, the theoretical model of the plunge milling of an impeller with fixed rotating axis is summarized as an optimization problem of finding the maximum inscribed general cylindrical surface of the impeller's tunnel surface. This optimal problem is then divided into two processes to reduce the computational difficulties, i.e., the determination of the direction of the ruled line and the determination of the directrix of the general cylindrical surface. A least square model and its corresponding solving methods for the determination of the direction of the ruled line of the general cylindrical surface are presented. Based on these, the tunnel surface is projected on a plane in the direction of the ruled line, and the directrix of the general cylindrical surface is resolved based on the intersecting operations between the related curves. For the plunge milling of the impeller's tunnel surface, the acquired directrix is used as the boundary curve of the machining area, and the axis of the flat end mill is set to be parallel to the direction of the ruled line. An iterative algorithm for determining the cutter center and the safe height of the flat end mill is given. Finally, the effectiveness of the proposed methods is verified by a numerical example. The proposed method will be helpful for the enhancement of the rough milling efficiency and the evenness of the remained finish machining allowance of the impeller.