یک مطالعه بر روی توسعه سیستم برنامه ریزی عملیات به کمک کامپیوتر برای محصول الکتریکی با عملیات خم و پر سر و صدا

This paper describes a research work of developing computer-aided design of product with bending and piercing operation for progressive working. Approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results, and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer. It is composed of four main modules, which are input and shape treatment, flat pattern layout, strip layout, and die layout modules. The system is designed by considering several factors, such as bending sequence by fuzzy set theory, complexities of blank geometry, punch profiles, and the availability of a press equipment and standard parts. The strip layout and die layout drawings automatically generated by formularization and quantification of experimental technology will make minimization of trial and error and reduction of period in developing new products. Results obtained using the modules enable the manufacturer for progressive working of electric products to be more efficient in this field.

Standardization of design is need of the time according to trends of miniaturization, lightening, and speeding in nowadays industry. Shear forming by which parts with a desired shape are manufactured from a sheet metal especially using a punch and a die needs this kind of standardization with a view to compatibility and accuracy of components. But experiences and intuitional decision have mostly accomplished strip layout and die layout of forming as piercing and bending. In order to solve this problem, researches have been reported automation of computer-aided process planning for the designed product by formulizing these experiences of skillful engineers [1], [2], [3], [4] and [5]. Nakahara et al. [1] introduced the system for a progressive die design. Wang and Chang [2] studied on determination of the bending sequence in progressive die design, and See Toh et al. [3] developed system for feature-based flat pattern. Also, Choi et al. [4] and [5] developed the automated process planning and die design system for blanking or piercing of irregular shaped sheet metal product. In this study, the developed system decides the sequencing process of electric product with intricate piercing and bending operations by considering several factors on bending and adopting fuzzy set theory. It constructs fuzzy matrix for calculating fuzzy relationship value and determines the optimum bend by combining several rules with fuzzy reasoning. The strip layout module of the system is able to carry out bending and piercing operations of 3D electric product. Using the data of the strip layout, the die layout module generates the parts of a die as punch, die, die plate, punch plate, stripper plate, guide plate, guide pin, spring, fastener, dowel pin, and lifter.

The study developed an automated design system for process planning and die design by fuzzy set theory for electric product with intricate piercing and bending operations. This system quantifies techniques and experiences needed in designing die sets and standardizes design rules for formulating procedures for design. It carried out recognition of 3D shape and performed process planning according to sequences decided in the strip layout module with information of shape data obtained by shape recognition method. The strip layout drawings of the products with intricate bending operations are coincided with those of actual workshop by the value of FVM set. It has the advantage that a novice who may have some knowledge of tool design can use it. We reduced design and working time as forming each part easily by making use of these results generated in this system. As the design procedure and experience of field experts are quantified, even a novice is able to obtain the results of skilled engineers. The standardization of the design, the high precision of die, the preparation of material, the purchase of standard products, and reduction of design time not only expand consumer markets due to the rapid supply of product, but also play an important role in building FMS system as an integrated CAD/CAM system.