Development of a CAPP system for multi-tasking machine tools to deal with complicated machining operations

摘要

There is always strong impetus to shorten the manufacturing lead-time of mechanical products. Seeking higher efficiency through multi-tasking machine tools has attracted attention for its many advantages in the field of machining. There are a lot of different kinds of multi-tasking machine tool structures that have both turning and milling functions. Therefore, the machining operations are generally complicated, and it takes a great deal of time and labor to generate numerical control (NC) programs. To reduce preparatory time, computer aided process planning (CAPP) systems are needed to automatically determine machining process parameters such as machining sequence, cutting tool, cutting conditions. This study aims to develop a CAPP system for multi-tasking machine tools with two confronting spindles to deal with complicated machining operations. Chucking switch for a workpiece between two confronting turning spindles is introduced to realize 6-face machining of complex target shapes A workpiece shape and target shape are divided into two domains related to the main turning spindle side and sub turning spindle side, respectively. Then, the machining features can be recognized from each domain according to the assumed spindle side. Moreover, parallel machining using plural functions of turning and milling can be achieved by recognizing machining features that are simultaneously machined by the same machining method. The results of case studies confirmed that the developed CAPP system is effective for NC program generation of complicated machining operations on multi-tasking machine tools.