Research On Remanufacturing Process Quality Control Methods Of Used Machine Tools

The used machine tools remanufacturing is as one of the important part of recycle economy and sustainable economy which is a great significance for realizing the sustainable development of society.The quality of the used machine tools remanufacturing product is the important factor restricting the development of remanufacturing enterprise.There are many uncertainty in remanufacturing system: the uncertainty of use blank service condition,the uncertainty of its quality defects and the uncertainty of organizational structure.That leads to the difficulty of used of machine tool remanufacturing process quality control and makes it hard to assure remanufacturing product quality.Based on this,the remanufacturing process of used machine tools is taken as the research object,the abnormal quality online monitoring,abnormal quality recognition and abnormal quality diagnosis and adjustment is studied based on the characteristics of the uncertainty of remanufacturing process.And the main research contents are as follows:(1)Aiming to the uncertainty of blank,the remanufacturing processing quality control method is proposed based on dynamic,abnormal distributed EWMA control chart.The control chart is based on Wilcoxon rank-sum test in non-parametric method,using rank statistics to obtain the results that are irrelevant to the samples and realizing the real independence with distribution types.Then,the online observation points are updated by moving the data window of the control chart and dynamic smooth parameters are obtained by the score function,establishing the EWNA control chart of the dynamic and abnormal distributed remanufacturing processing and quality and realizing the adaptive monitoring of the remanufacturing processing.(2)Aiming to the small quality sample in remanufacturing process and the difficulty of quality abnormal recognition,the Principal Component Analysis(PCA)based on CS decomposition Bayesian is proposed.The idea of CS decomposition Bayesian spatial estimation and feather subspace is introduced to the traditional PCA to solve the problem that traditional PCA need large sample in order to the abnormal quality recognition of remanufacturing process in the small sample.(3)Aiming to the uncertainty between abnormal quality and leading factors in the remanufacturing process,remanufacturing process quality abnormal diagnosis and adjustment system based on rough set theory is proposed.The importance of manufacturing quality factors relative to the remanufacturing process quality characteristics is calculated by using rough sets theory and knowledge.During the size of importance of different factor,the abnormal quality is traced,the causes of abnormal is found out and the remanufacturing process is adjusted to realize the remanufacturing process abnormal diagnosis and adjustment.(4)The remanufacturing processing of the guide rail of the used TPX6113 is taking as an example.The proposed quality control method of used product remanufacturing process based on dynamic and non-normal EWMA control charts can rapidly detect the abnormal quality.After the process appears abnormal,the method based on the improved PCA quality abnormal recognition model can rapidly detect the types of abnormal quality.Then remanufacturing abnormal quality is diagnosed by using quality diagnosis based on rough set model.And abnormal quality abnormal reasons are obtained after diagnosis and the process is adjusted.The results show that the proposed method well solves the problem of the remanufacturing process quality control,which proves the effectiveness and feasibility of the proposed method and provides a more effective method in remanufacturing quality control.