A methodology for the manufacture of forming tools incorporating complex surface geometry with minimum computer resources

Abstract This paper presents a methodology for the manufacture of tools embodying true three-dimensional free-form surfaces using PC-based two-and-a-half axis CADCAM systems. The numerical control machining of free-form surfaces is usually accomplished utilizing minicomputer or mainframe computer aided design and manufacturing (CADCAM) systems. The resulting NC data are suitable for either three axis or five axis machining, dependent upon machine tool type/capability and CAM package complexity. However, the cost of such packages and systems precludes their use in smaller companies with only an occasional requirement for components embodying free-form surfaces. The increasing availability of powerful yet reasonably priced personal computers (PCs) coupled with improving software provides such companies with a far cheaper alternative approach. However, a common feature of PC-based CADCAM systems is that they are limited to two-and-a-half axis machining for all but special applications such as three axis canted Z-plane milling or four axis wire electro discharge machining. All the main functions performed on mainframe systems can be performed on personal computers, such as toolpath generation for free-form surfaces, cusp height determination and change in shape and volume which may be used for component springback compensation.