| The computerization of forging geometry design is essential in preserving gradually disappearing design knowhow and providing much needed productivity gains for the forging industry. To automate forging design, the principles and the actual practices of forging design were obtained through an extensive literature review and expert forging designer interviews. It was found that forging design can be modelled by a hierarchical network structure with data driven reasoning as the basic problem solving strategy. It was also found that many forgings can be decomposed into rib and web components. Thus, the design of such forgings can be done by evaluating and modifying (if necessary) these components, one at a time, to satisfy the constraints imposed by the forging production requirements. Due to the diversity of the knowledge and problem solving techniques required for forging design, a combination of knowledge based algorithmic techniques was used to develop an Automated Forging Design (AFD) system. In addition, forging design knowledge is partitioned, based on the forging design model, in order to facilitate control. The AFD system consists of two basic modules: (1) Forging Design Decision Making Module--using "frames" to represent the forging part, design tasks, and design guidelines, and "data-driven" reasoning to control the design process; (2) Forging Geometry Manipulation Module--using a "syntactic" approach for part geometry decomposition, "analytical geometry" techniques for geometry modifications, a "constructive geometry" approach for part geometry construction, and "interactive computer graphics" techniques for design modifications. Given a set of design specifications, i.e. machined part geometry, processing conditions, and special design considerations, AFD designs the forging section geometry automatically. Special considerations were also given to flexibility and adaptability of the system. With minimum efforts, a user can modify the design rules and available resources to make the AFD to function according to his own forging design environment. Initial results from AFD show that it ca be a powerful tool for designing geometries for the rib-web type of forgings. |
