توسعه یک سیستم یکپارچه برنامه ریزی عملیات به کمک کامپیوتر برای محصولات کار فشرده سازی

This paper describes research work in developing an automated computer-aided process planning system for a hot forging or blanking product by press working. The computer-aided process planning system written in AutoLISP on AutoCAD using a personal computer and in I-DEAS Drafting Programming Language on the I-DEAS Master Series Drafting with workstation in hot forging and blanking requires many kinds of technical and empirical skills. An approach to the computer-aided process planning system is based on knowledge-based rules and a process knowledge base consisting of design rules is built. Based on the investigation and collection of knowledge of the processes, the methodology adopted to develop this system is elaborated in this paper. This integrated computer-aided process planning system is composed of two main modules: hot forging and blanking modules. It is designed by considering several factors, such as the complexities of the blank geometry, the punch and die profiles, the availability of press equipment, and standard parts. Results obtained using the modules enable the designer and manufacturer of forging or blanking dies to be more efficient in this field.

Worldwide mechanical communications, electronics, and light industries have been booming for a few decades at an even accelerating speed. This is partly due not only to the advances in basic sciences and technologies but also to the development of metal forming process supported equipment and die making technologies. Among others, wide applications of computer-aided process planning in hot forging or blanking will result in the mass production of high-quality metal parts at a low cost and high productivity. Metal forming, by which parts with a desired shape are manufactured from metal or sheet metal using a punch and a die, especially needs this kind of standardization for the compatibility and accuracy of components. However, mainly the experience and intuitional decisions of skillful engineers have accomplished metal forming with press working operation. Those skillful engineers also manufacture parts of the die and punch according to such a process planning drawing. In order to solve this problem, considerable interests are focused on reducing the design time required for designing and manufacturing. Thus it is necessary to develop computer-aided tools for automated process planning and die design to further augment the competitiveness of industry. The core of these tools is an integrated information model, which captures the complete information needed by various applications such as feasibility analysis, process planning, and process simulation. Research have been reported on the automation of computer-aided process planning and manufacturing for the designed product by formalizing the experience of skillful engineers [1], [2] and [3]. Nakahara et al. [4] introduced a system for a progressive die design. Also recently Choi et al. [5] and [6] developed a compact and practical CAD system for the blanking or piecing of irregular shaped sheet metal products and stator and rotor parts.

The study developed integrated computer-aided process planning system to carry out automated process planning for hot forging or blanking product. It has the following features: 1. It quantifies the techniques and experience needed in process planning for hot forging or blanking product and standardizes design rules for formulating a design procedure. 2. Based on knowledge-based rules, the integrated computer-aided process planning system automatically recognizes a product drawing and transfers the recognized product drawing data into corresponding sub-modules of the main module to carry out process planning of the input product. 3. The finisher die design sub-module of the hot forging module and the strip- and die-layout sub-modules of the blanking module can generate a process planning drawing for a hot forging or blanking product into graphic forms on the screen. The system has the advantage that a novice who may have only limited knowledge of tool design can use it. In order to further develop this powerful tool in this field, the system will be studied continuously. It also considers the working conditions and characterization of various machine tools. The system will implement more quantified techniques and the experience used in the actual workshop to generate automatically a die set drawing suitable to the process planning of press working products.