COMPUTER AIDED PROCESS PLANNING SYSTEM FOR PRISMATIC PARTS

Abstract

In the present work, a Computer Aided Process Planning System for prismatic parts has been developed. The system referred as CA.PPS PRINTER (Computer Aided Process Planning System for PRismatic parts developed at INdian institure of TEchnolgy Roorkee) is intended to generate process plans for components machined on milling, shaping and drilling machines. It is designed in a modular fashion and consists of different modules for performing the various activities related to the generation of process plans. These modules are grouped into three subsystems, namely; Subsystem for Feature Recognition (SFR), Subsystem for Machining Planning (SMP) and Subsystem for Setup Planning (SSP). To support the activities of these subsystems all the information required for the execution of this system is stored in the following three main databases; DataBase for Feature Recognition (DBFR), DataBase for Machining Planning (DBMP) and DataBase for Setup Planning (DBSP). These data bases are linked to their respective subsystems. The major input for this system is the CAD file representing the CAD data of the prismatic component. From the CAD file, first all the faces of the part are identified in a predetermined order and represented in a form suitable for recognizing the manufacturing features of the component by applying the feature recognition strategy developed in the course of this research work for prismatic parts. Under this strategy only a few faces are considered in order to detect the presence of depression and protrusion type of primitive features such as step, slot, prismatic hole, pocket, circular hole, rectangular projection, T-slot, boss etc. as well as some complex features resulting from the interactions of primitive features. The recognized features are then represented by the following three characteristics which are used in the ii machining planning and setup planning activities: i) dimensions of the feature, ii) faces forming the feature and iii)faces providing access to the feature