Abstract:

The dynamic operation behavior of the computer numerical control(CNC) machine tool was analyzed and a stochastic Petri net model was built for its reliability. The corresponding status at every failure time of every subsystem was obtained by the total failure time method. A dynamic availability model was established for the CNC system and its subsystems by the Monte-Carlo simulation of the Petri net. Taking 261 fault data of 7 CNC machine tools as examples of analysis, the histories of the availability of the CNC machine tool and its subsystem were obtained, providing a basis for establishing a reasonable maintenance policy and predicting the availability status for the CNC machine tool.

Key words: CNC machine tool, availability model, stochastic Petri net, Monte-Carlo simulation