Generation of Feature-Based Models

Abstract

Often there can be a number of ways to perform machining operations on a stock to produce a part, and only some of them are cost- and quality-effective. To determine the best machining sequence, it is necessary that each sequence of machining operations be evaluated and the best sequence be chosen. A feature-based model is a sequence of machining operations that when performed on a stock produces a part. This paper describes a way to generate all the feature-based models for a design of a part so that the designer can choose the best sequence of machining operations by evaluating each of the feature-based models.A part could be prismatic, sculptured or rotational, but the scope of this project is restricted to rotational parts (i.e. parts that are rotationally symmetric, about the horizontal axis). A rotational part can be reduced to two dimensions, without loss of information, by taking a cross section going through its rotational axis. The purpose of the project was to develop an algorithm that operates on the two-dimensional representation of a rotational part and generates feature-based models.There are drafting packages which have provisions for describing three-dimentional parts and some of them also support tolerance and surface finish descriptions. Most of the packages however, do not support feature extraction and generation of feature-based models. The system developed in this project provides a simple X-window user interface for describing a part and a specifying the features, and generates the feature-based models for the part.