An intelligent Knowledge Based System for Manufacturability Evaluation and Generation and Evaluation of Alternative Processes for Conventional and Unconventional Processes

摘要

Product designers sometimes select poor design parameters, because they do not have enough knowledge about process capabilities, good practice and impact of design parameters on manufacturing processes. This increase product development cycle time and cost. Machining cycle time and cost can be reduced by access to suitable manufacturability evaluation and generation of alternative process for selection of optimum process. This eliminating design errors and avoiding difficult and expensive manufacturing features before manufacturing process begins. This paper addresses the concept and development of an Intelligent Knowledge Based System (IKBS) in concurrent engineering environment based on object oriented technique for conventional processes (i.e. drilling, reaming, boring, slot drilling, end milling, tapping, etc.) and unconventional processes (i.e. electrochemical machining (ECM), electro-discharge machining (EDM), electrochemical arc machining (ECAM), ultrasonic machining (USM) and wire-electro-erosion-dissolution machining (Wire-EEDM)) for manufacturability evaluation and generation of alternative processes for improved product design. Design specification is acquired through a feature-based approach. Description of eight different classes of design features is obtained. The attributes of different work-piece material types, different types of tool metals, two electrolytes and attributes of two dielectric compositions are stored in databases. For each design feature (i.e. hole, pocket, slot, etc) information needed in manufacturing, such as machining cycle time and cost and penetration rate and etc. are estimated. Finally, for each design feature for the same design specification, machining time, cost and penetration rate for alternative processes (six conventional and six unconventional processes) are generated and compared automatically with each other. The system is used for optimization of design and manufacturing processes. It can be used as a process of iterative redesign, which suggests a way of using process information to find ways of reducing the cost of each design feature. It also estimates the optimum operation parameters for each process or process sequence which balances between quality and manufacturing cycle time and cost and offer designers immediate feedback about parameters such as the machining cycle time, cost and quality, and give some advise to manufacturing engineers related to manufacturing parameters such as feed, speed, penetration rate, machining cycle time and cost saving.