Analysis And Research On Reliability Technology Of CNC Gear Form Grinding Machine

Since the advent of CNC gear form grinding machine,it has been positioned as a mid-to-high end equipment and won the widely used.At present,China's research in this field has been made considerable progress;however,there also existed some dilemmas such as insufficient technical competitiveness,low degree of autonomy and difficulty in going global.That was because our products hard to reach the international advanced level in core indicators,such as the reliability,consistency and stability.Therefore,carrying out research on the reliability of machine tools is great significance to the development of China's industry and the realization of manufacturing power strategy.Based on the research trends of reliability technology at home and abroad,this paper has carried out a series of in-depth research around the reliability technology of CNC gear form grinding machine.The research work of this paper mainly includes:(1)Research on the reliability modeling method.The research mainly covered the reliability evaluation feature quantities and their relationships,the establishment,solution and verification of reliability distribution models.Among them,the focus is on the solution and verification of the distribution model,the process of parameter estimation based on MLE is derived,and the distribution model verification methods such as Mann method,gray relational analysis grade method and error area ratio are concluded.This research provided a basis for reliability evaluation.(2)Research on the reliability evaluation method of small samples.In view of the small sample problem,this chapter studied the expansion algorithm of RBF neural network based on the traditional reliability modeling and evaluation process.This algorithm can better expand the reliability data after continuous learning and adjustment;therefore,a new reliability evaluation process of CNC machine tools was proposed.Finally,the established method is used to realize the reliability evaluation of CNC gear form grinding machine,and it is verified that this method has unique advantages and effectiveness in dealing with the reliability evaluation of small samples.(3)Research on the fault synthetic analysis for CNC gear form grinding machine.Firstly,the vibration signal fault feature extraction technology based on EMD is analyzed,and the experiment verifies that this method is usable and effective for fault detection of machine tools.The second is to study the FTA analysis,by establishing and analyzing the fault tree of each main subsystem,the logical causality relationship between the machine tool fault events is clarified,the system fault spectrum and the existing weak links are analyzed.The research results provided reference for the rapid response to failures and the extension of the time between failures.(4)Research on the method of reliability risk assessment based on fuzzy FMECA.Firstly,this chapter analyzed the main failure modes of the machine tools subsystem and proposed corresponding improvement measures.Then,aiming at the problems existing in the traditional risk evaluation,a fuzzy risk evaluation model was proposed to complete the reliability risk evaluation of the CNC gear form grinding machine.The evaluation results provided relevant references for taking reasonable preventive measures to reduce the adverse effects of faults and improve the reliability of the whole system.Finally,based on the research work,the reliability improvement process of CNC gear form grinding machine was established,which has important guiding significance for the continuous growth of machine tools reliability.