| CNC machine tool is the “Mother Machine” for intelligent manufacturing in equipment manufacturing industry.It is an important sign to measure the development level and product quality of national equipment manufacturing industry.The maintenance support level of CNC machine tool is the key to the long-term safe,reliable and economic operation of CNC machine tool.With the continuous improvement of people's requirements for product quality and customization,CNC machine tool is becoming more complex,integrated and intelligent,and new challenges and requirements are put forward for their maintenance support technology.Due to the increase of the composition and influencing factors of CNC machine tool,the probability of malfunction and functional failure gradually increases,and the difficulty of their maintenance support is also increasing.The existing extensive maintenance support mode cannot guarantee the safe,reliable and economical operation of CNC machine tool.Therefore,it is necessary to carry out in-depth research on the maintenance support technology of CNC machine tool,trying to explore a set of lean maintenance support technology to ensure the safe,reliable and economic operation of CNC machine tool.In view of the shortcoming of the existing maintenance support technology,with the CNC machine tool as the research object,combined with the maintenance support characteristics of CNC machine tool,a set of knowledge-based lean maintenance support architecture for CNC machine tool is established.The architecture makes full use of condition monitoring technology and digitalization technology,focusing on key technologies such as maintenance BOM-centered data organization and management,fine management and control of maintenance support process,fine planning and precise utilization of spare parts resources,etc.,and knowledge-based decision-making method to solve the business problems in the field of maintenance support,such as diagnosis,planning and analysis,so as to reduce the maintenance support cost,improve maintenance support efficiency,and improve the safety,reliability and mission success of CNC machine tool.The main research contents of this paper are as follows:(1)Lean maintenance support architecture of CNC machine toolIn view of the insufficient capability and low efficiency of maintenance support of CNC machine tool,based on the analysis of the maintenance support characteristics of CNC machine tool,the research of maintenance BOM organization and management,and the deep mining of maintenance support business requirements,we have established a set of knowledge-based lean maintenance support architecture.The architecture is composed of six parts: knowledge-based platform,maintenance BOM management,condition monitoring and periodic maintenance,maintenance support management,spare parts management and service,and data exchange and service center.Combined with the practical application requirements of the enterprise,a set of scientific and reasonable business process is designed to meet the needs of preventive maintenance support for CNC machine tool.Finally,some key technologies involved in the architecture are discussed and in the follow-up chapter has carried on the detailed elaboration.The establishment of the architecture can reduce the maintenance support costs,improve maintenance support efficiency,and improve the operational safety,operational reliability and mission success of CNC machine tool.The architecture has been initially applied to the CNC workshop of an aviation enterprise and achieved good results.(2)Reliability guarantee strategy of monitoring system for key parts of CNC machine toolAiming at the problem that the operation yield is seldom considered in the present monitoring system,from the perspective of sensor network yield,a system reliability model is constructed,and the yield importance is defined.A reliability guarantee strategy of monitoring system based on yield importance is established.Through this strategy,the sequence of spare nodes is allocated with the objective of optimal operation yield and the constraints of system reliability and running time.(3)Flexible multi-mode knowledge-based decision-making technology for maintenance support processIn order to solve the problems of low maintenance support efficiency and increasing difficulty of maintenance support for CNC machine tool,a flexible multi-mode knowledge-based decision-making technology for maintenance support process is proposed,which is mainly studied from four aspects: knowledge representation,knowledge acquisition,knowledge processing engine,and knowledge scheduling and control.The feasibility of the proposed technology is verified by the maintenance support process plan,which is the key link in maintenance support process of CNC machine tool.The proposed technology provides an effective method for solving the problem of business decision-making in the field of maintenance support,which is characterized by many business links,high technical difficulty,intensive knowledge,and strong experience and inspiration.The proposed technology realizes high-level knowledge-based rapid decision support.(4)Data-driven predictive spare ordering and replacement strategy for mechanical critical componentsIn order to solve the problem of insufficient spare parts support for critical components in the existing maintenance replacement strategy,a degradation model and a remaining useful life model are established based on the performance degradation data of the critical components in CNC machine tool.The joint optimization strategy of spare parts ordering and replacement based on the remaining useful life model and random ordering cycle is formulated with the constraint of component availability threshold.At the same time,in order to deal with the unexpected failure of components and reduce the invalid waiting time,the proposed strategy is to speed up the delivery of spare parts by means of half-way rush.The proposed strategy provides a theoretical basis for ensuring component safe operation,improving service quality and reducing maintenance cost.(5)Maintenance-oriented spare parts sharing service and allocation optimizationIn order to solve the problem of low service capacity and low allocation level of spare parts,firstly,a new mode of spare parts management based on maintenance BOM is adopted to break through the barrier between spare parts management and CNC machine tool maintenance,so as to realize maintenance-oriented spare parts management and precise service,and improve the utilization of existing spare parts inventory.Secondly,aiming at the conventional spare parts ordering,the spare parts allocation optimization method is studied from the angles of the system spare parts satisfaction rate and the system reliability,in order to minimize the spare parts allocation cost under the premise of guaranteeing the task duration.(6)Design and implementation of maintenance support system for CNC machine toolBased on the construction of maintenance support architecture of CNC machine tool,combined with the practical application requirements of the enterprise,a knowledge-based maintenance support system for CNC machine tool is designed and developed.Firstly,the software architecture of the system is designed to realize the system construction based on the knowledge-based platform.Secondly,the functional modules such as maintenance BOM management,condition monitoring,maintenance support management,spare parts management and knowledge-based platform are designed.Thirdly,B/S architecture and‘Java+Matlab+DL4J+Weka' hybrid programming are adopted to realize the development of the system software.Finally,the feasibility of the maintenance support system is verified by the practical application in the CNC workshop of an aviation enterprise,which provides a reference for the future application in other high-end equipment maintenance support. |
PDF Full Text Request