Expert system for multi-stage cold-forging process design with a re-designing algorithm

Abstract

Cold forging has recently become one of the competitive technologies in manufacturing. In order to impove the productivity of cold forging at low production cost, an integrated systems approach is necessary in handling the material preparation and the optimum process design considering the forming machines, tooling, and operation, including quality control. As the first step toward this approach, an expert system for multi-stage cold-forging process design for axi-symmetric geometries with or without a hole in one end has been developed using Prolog language on IBM 486 PC. The system consists of a user interface, a system shell, a material data-base, and a design rule-base. According to the given input data, the system generates the forgeable geometry and the basic process design, depending on the initial billet size and material or the order of upsetting and forward extrusion. In addition, it can provide a flexible process re-design based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution and the level of the required forming loads at the last forging step by controlling the forming ratios. The required forming loads and global strain distributions at each step are calculated and displayed on a PC monitor. The designed process sequences can be obtained by AutoCAD or a text file including the dimensions of the drawing. The system developed will be useful in reducing trial-and-error by design engineers in determining the diameter and height of the initial cyclindrical billet from the final product geometry and the intermediate necessary sequences.