Research On Methods Of Reliability Assessment For CNC Machine Tools

Equipment manufacturing industry, with the core technology of CNC tool machine, is the foundation of manufacturing industry. Nowadays, CNC tool machine tends to be faster, more accurate and more advanced, and to maintain the high reliability and accuracy stability of CNC machine tool has become extremely crucial for the development of the industry.To solve this problem, research about enhancing the reliability growth is in great demand.Reliability estimation is the major part of reliability growth technology. Only through right method to evaluate the state of CNC machine tool can we improve the machining process.Especially to the problem of assessing the CNC machine stability of accuracy, the regular way is not suitable for the long-term, small-sample conditions.As a result, new method needs to be proposed.This research is carried out under the background above, and mainly focused on solving the following questions:The paper introduced the basic theory of reliability assessment.And then, existing methods and conceptions of reliability estimation were sorted and shown on the paper.Later, combined with the existing methods of reliability estimation, the paper presented the method system of CNC tool machines, according to the characteristics of the functions. Eventually, the paper explained the reliability and accuracy stability of CNC machine tools separately.First of all, treatment of the fault data of repairable system was interpreted. For generic fault of CNC machine tools, the method to introduce to data treatment of repairable system into CNC machine tool reliability estimation solved the problem of lack of samples.Secondly, to predict the accuracy failure cycle of CNC machine tools, the degradation-data-based method for reliability estimation was applied in the stability of accuracy for CNC machine tools. And the method of support vector regression helped to fit the track of degradation.