Research Of Assembly Reliability Control Technology Of CNC Machine Based On Meta-action

Since the Second World War, more and more people have known that reliabilityplays an important role in products production and usage process, and the application ofreliability engineering technology is becoming wider and wider. With the developmentof science and technology in our country, the domestic CNC machine tool industry iscontinuously improving for itself, while the progress in reliability seems lagging behind.Most enterprises focus mainly on the application reliability of CNC machine tool, withlittle care about the reliability control in production process. As reliability is thought tobe manufactured out in the first place, the production process reliability should becontrolled well in order to improve the reliability of CNC machine tool. Assembly is thelast stage of finishing product manufacturing, which is also an important productionprocess of domestic CNC machine tool manufacturers, and assembly quality directlyaffects the product reliability. In order to ensure the product reliability, some necessaryproduct assembly requirements should be proposed and guaranteed in the assemblyprocess.Combined with the NSFC project, based on the theories of meta-action and itsassembly relationship, with the integration model of QFD and FMECA as the technicalmethod, and the pallet exchange of domestic CNC machine tool THM6380as anexample, the assembly reliability control technology of CNC machine tool based onmeta-action is studied and the targeted assembly reliability monitoring system isestablished in this paper. The main contents are as follows:①Meta-action and meta-action assembly unit are defined, and also the fourelements of which meta-action consisits of: middleware, power source, executive parts,supportive parts and fasteners.The concrete implementation steps of assembly treeconstruction based on meta-action is given. Based on mata-action, with reliabilityanalysis tools as techniqual methods, and reliability control based on meta-action aspurpose, the assembly process is compiled, then the basic principles of assemblyprocess reliability control are expounded.②For deeper reliability analysis on the assembly failures, FMECA analysis iscarried out on the assembly failures of meta-action. With the pallet changer ofmachining center as an object, assembly failure mode, effect and criticality analysis is carried out on the machine tool, and then the RPN values are obtained, which providesdata support for key assembly processes extraction later.③To extract the key assembly processes based on meta-action in order to controlthe assembly process reliability of CNC machine tool, the integrated model of QFD andFMECA is established firstly, in which the fuzzy theory is applicatedl,and then theweights of assembly processes are calculated and sequenced,finally the principle of80/20is used to extract the nine key assembly processes based on meta-action (keyreliability control points).④Finally, the assembly reliability monitoring system establishment process isexpounded in detail. The functional requirements of assembly reliability monitoringsystem are analyzed, the assembly reliability control flow of Sichuan Push-NingjiangMachine Tool Co. Ltd and the reliability-driven assembly process based on meta-actionare studied, and then the specific assembly reliability monitoring system based onmeta-action is established, with system software architecture, overall function frame,and functional modules described.