A hybrid approach to automatic generation of NC programs

Purpose: This paper describes AGNCP, an intelligent system for integrating commercial CAD and CAM systems for 2.5D milling operations at a low cost. Design/methodology/approach: It deals with different machining problems with the aid of two expert systems. It recognizes machining features, determines required machining process plans, cutting tools and parameters necessary for generation of NC programs. Findings: The system deals with different machining problems with the aid of two expert systems. The first communicates with CAD system for recognizing machining features. It is developed in LISP as machining features can be properly represented by LISP codes is ideal for manipulating lists and input data. The second expert system requires extensive communications with several databases for retrieving tooling and machining information and VP-Expert shell was found to be the most suitable package to perform this task. Research limitations/implications: 2.5D milling covers a wide range of operations. However, work is in progress cover 3D milling operations. The system can also be modified to be used for other activities such as turning, flame cutting, electro discharge machining (EDM), punching, etc. Practical implications: Use of AGNCP resulted in improved efficiency, noticeable time savings, and elimination of the need for expert process planners. Originality/value: The paper describes a method for eliminating the need for extensive user intervention for CAD/CAM integration.