Research On Maintenance Strategy For CNC Machine Tools Based On Reliability Analysis

CNC machine tools are the modern mother machine with high technology, which are indispensable fundamental equipments making up digital enterprises. Their maintenance has great effect on ensuring consequence of production and improving economic benefit. However, the present maintenance for CNC machine tools lacking of supporting of maintenance theory and maintenance decision strategy, are mainly depend on traditional maintenance way and maintenance experience, casing "lose maintenance" and "over maintenance".This paper facing to the above phenomenon includes some contents shown as follows.(1)This paper brought the failure dependent theory into reliability analysis based on summarizing the failure characters of CNC machine tools. A type of reliability analysis model based on failure rate interaction was constructed.(2)A method based on criticality analysis was proposed to ensure the maintenance strategy of subsystems of CNC machine tools. Summering the maintenance character of CNC machine tools, a method on confirming the maintenance methods for components based on the consequence of reliability analysis and criticality analysis.(3) According to the fact that the maintenance of CNC machine tools is imperfect, a periodic maintenance decision strategy model is proposed based on imperfect maintenance for systems of CNC machine tools. The parameters in the model are optimized by minimizing the maintenance cost per unit time.(4)On the base of reliability function and maintenance strategy of subsystems, a system maintenance decision strategy model based on group maintenance was proposed considering the failure dependence and economic dependence. Then the optimize steps were president.All the theories, models and methods were validated applying the failure data of some type CNC machine tool. Finally, a maintenance plan for this CNC machine tool is given.