Système et gestion des télécommunications

A Rule-Based Two-Level Classification Approach for Recognition of Machining Features from 3D Geometric Models

Abstract

Alan C. Lin and Riona Ihsan Media

In this paper, a rule-based approach is presented to enhance the capability of recognizing both intersecting and isolated features with form variation. Features are recognized and classified into a two-level classification. In the first level, edge and loop types are utilized to categorize the features into two different groups, namely single-entry feature (SEF) and multiple-entry feature (MEF). In the second level classification, hole and pocket features can be recognized by either convex internal loops or concave external loops. Meanwhile, step and slot features can be recognized by hybrid loops and the total number of tool accessible directions. Besides, the transitional features are categorized into simple and rounded features according to surface types and the number of face sets. Non-planar surfaces including cylinder, sphere and cone are also examined. Finally, special machining features such as T-slot and dovetail slot are also evaluated by means of pre-defined rules.

The proposed approach has been implemented using NX Open in Siemens NX as the platform for system development. Five real industrial parts are used as test examples. The result shows that eighteen feature types are successfully recognized to accommodate intersecting and isolated machining features with variable topology.