Research On The Fault Analysis Technique For CNC High-speed Punch Press

CNC high-speed punch press is a kind of automatic stamping equipments whichworks efficiently and precisely on the automatic sheet stamping line. As machine tooltechnology continues to progress and the CNC high-speed punch press becomesincreasingly intelligent and precision, requirements for its reliability are much morehigher.At present, the level of reliability of China’s domestic CNC high-speed punchpress compared with foreign ones made in advanced industrial countries still have abig gap and the reliability of the product direct impact on market competition.Therefore, it is our top priority to improve the reliability of domestic CNC high-speedpunch press to deal with today’s highly competitive environment of machine toolmarket.Fault analysis is an important part of the reliability growth activity of the CNChigh-speed punch press. In this master dissertation, took Domestic CNC high-speedpunch press as the research object and focused on the research of the CNC high-speedpunch press fault analysis.This paper took the FTA fault analysis method to analyse the CNC high-speedpunch press. In order to clarify the faults and their causal logic of the CNC high-speedpunch press, the CNC high-speed punch press was divided into8subsystems and thenestablished the CNC high-speed punch press subsystem fault tree and the whole faulttree. The minimal cut sets of the CNC high-speed punch press fault tree bottom eventswere determined by using qualitative fault tree analysis. For no fault or lack of dataledding the quantitative fault tree analysis to a difficult situation, this paper studied aCNC high-speed punch press fault tree bottom event importance analysis methodbased on fuzzy theory.In this method, a detailed way was given on how to determinethe weights of experts and how to translate fuzzy numbers into fuzzy fault rates. Thismethod was applied in the CNC high-speed punch press fault analysis and the CNChigh-speed punch press fault tree bottom event importance rank and subsystemimportance rank was acquired.In order to consider the reliability factors of the failure probability and failuresevere degree in the CNC high-speed punch press fault analysis, this paper also took the FMECA fault analysis method to analyse the CNC high-speed punch press. First,this paper classified the failure modes, fault locations, fault causes of the CNChigh-speed punch press.Then by using statistical analysis, figured out the frequentfault sites and modes of the CNC high-speed punch press based on historical faultdata. Finally, the CNC high-speed punch press FMEA table was accomplished and thereliability weak links of the high-speed CNC punch press were identified by usingharmfulness matrix analysis.In order to take the complementary advantages of the FTA and FMECA analysis,this paper presented the CNC high-speed punch press FTF fault analysis method.Forthe defect that the reverse FTF is easy to miss potential high critical failure mode, aimproved CNC high-speed punch press reverse FTF was presented and thisimprovement also can simplify the FMECA. For the shortcomings of traditionalcriticality analysis, this paper alse presented the improved criticality analysis methodfor the CNC high-speed punch press based on fuzzy and gray relational analysis anddeveloped an analytical model. The analysis model was applied to the fault analysis ofthe CNC high-speed punch press for acquiring the CNC high-speed punch pressfailure mode criticality fuzzy gray relational rank.For the results, the critical failuremodes of the reliability of the machine tool were identified to provide the basis forproposing and implementing reliability improvement approaches.On the basis of the CNC high-speed punch press fault analysis and according tothe results, the suggestions of the CNC high-speed punch press reliability supportingmeasures and improvement approaches were provided.