外文翻译--计算机辅助工艺过程设计.doc

Computer-Aided Process Planning According to the Tool Manufacturing Engineers Handbook, process planning is the systematic determination of the methods by which a product is to be manufactured economically and competitively. It essentially involves selection, calculation, and documentation. Processes, machines, tools, operations, and sequences must be selected. Such factors as feeds, speeds, tolerances, dimensions, and costs must be calculated. Finally, documents in the form of illustrated process sheets, operation sheets, and process routes must be prepared. Process planning is an intermediate stage between designing and manufacturing the product. But how well does it bridge design and manufacturing? Most manufacturing engineers would agree that, if ten different planners were asked to develop a process plan for the same part, they would probably come up with ten different plans. Obviously, all these plans cannot reflect the most efficient manufacturing methods, and, in fact, there is no guarantee that any one of them will constitute the optimum method for manufacturing the part. What may be even more disturbing is that a process plan developed for a part during a current manufacturing program may be quite different from the plan developed for the same or similar part during a previous manufacturing program and it may never be used again for the same or similar part. That represents a lot of wasted effort and produces a great many inconsistencies in routing, tooling, labor requirements, costing, and possibly even purchase requirements. Of course, process plans should not necessarily remain static. As lot sizes change and new technology, equipment, and processes become available, the most effective way to manufacture a particular part also changes, and those changes should be reflected in current process plans released to the shop. A planner must manage and retrieve a great deal of data and many documents，including established standards，mach inability data，machine