Transforming Workpiece Geometries into Lathe-NC Programs by Qualitative Simulation

A knowledge-based process-planning system for generating workplans for idealized lathe CNC machines is discussed. It transforms CAD-like diagrams of rotational-symmetric workpieces into abstract NC programs. To simplify development and evolution , declarative representations are used for all processing stages and steps, including a qualitative simulation of lathe turning. The version presented here, 'CAD2NC, was written entirely in RELFUN, a functional-logic language integration. Actually, 'CAD2NC is a mostly functional program consisting of three principal transformation components. First, a at term representation of the CAD-like geometrical raw data is parsed into a recursively classiied workpiece representation, exhibiting production-relevant workpiece features (e.g. `shoulders' and`grooves') through nested subterms. From this, a skeletal production plan is created by mapping features to sequential, com-mutative, and alternative subplans (ultimately, lathe actions). Finally, the abstract NC program is generated as a list of actions via a qualitative simulationèxecuting' the plan in order to x alternative subplans and sequentialize commutative ones.