Abstract
STEP-NC (ISO 14649) provides a new data interface for computer numerical control (CNC) machine tools. However, replacing the current ISO 6983 with STEP-NC is not only a matter of change in NC programming language but it also has a far-reaching and profound effect on the future CNCs and even on manufacturing systems. The CNCs are destined to evolve from pure controllers into integrated systems with both decision-making and control abilities. In this paper, strategies for implementing the STEP-compliant CNC systems are discussed and a framework for the autonomous STEP-NC controller is proposed. The controller is organized into two agents: the planning agent and the machining agent. This paper also provides a general discussion on issues about the part program interpretation, the on-line process planning. In order to support dynamic planning as well as meet the real-time requirements in NC machining, it is proposed to solve the on-line planning issues in two stages, i.e. the shop-floor planning and the real-time planning. It is also proposed to extend the feature-based algorithm to the interpolation stage.
Acknowledgements
The authors wish to thank National Natural Science Foundation of China (grant No. 50445004) and Natural Science Foundation of Shandong (grant No. Y2003F10) for their support of this research.