Abstract :
New three-axis CNC turning machines have been installed on shop floors of factories in the last few years. Although the machines are still particularly adapted to cylindrical work, they are also used for non-cylindrical machining. The third axis, C or Y, and separately driven, additional milling cutters have eliminated traditional limitations and opened new machining possibilities, i.e. turning and milling the non-rotational shapes. Even the advanced, integrated CAD/CAM systems do not support the milling and turning processes on three-axis CNC lathes or turning centers. Manual part programming for such machine tools, if available, does not facilitate the integration between design and manufacturing. For accurate part programming on three-axis lathes a new interpolation scheme must be applied, using both spiral segments of Archimedes and circular segments rather than linear segments as applied in CNC milling. Specialized, built-in software developed for the three-axis lathes enables to expand CAD/CAM integration to the same extent as in CNC multi-axis milling. The software includes modified postprocessors for three-axis lathes as well. The integrated processes of design and manufacturing are the most important prerequisites for effective concurrent engineering. In general, it means both better economics and quality of complex products, e.g. shaped rolls for rolling operations, cams and camshafts (non-ruled surfaces included), non-rotational shafts, airscrews, prostheses for total hip replacements, etc.
