Reliability Prediction And Fault Analysis Technology Of CNC Vertical Lathe Based On Fuzzy Theory

CNC machine tool is the core carrier of the modern equipment manufacturingindustry with healthy development, and is also the perfect combination of modernelectronic information technology and mechanical manufacturing technology, itscomprehensive level has become the important sign of measure a national creativity,technology level and the comprehensive national strength to a certain extent. Atpresent, with the deepening of the socialist modernization, domestic CNC machinetool both in research of development production and application field have been stableand rapid development, but compared with foreign advanced level, there is still existscertain gap, which is reflected in the reliability especially obvious. The low level ofreliability not only become the bottleneck which restrict the development of theindustry, but also is the direct reason of the domestic CNC machine tool low marketshare, the dependence on imports of the key functional components and high-gradeCNC machine tool. China is a big manufacturing country, enhancing home-made thereliability of domestic CNC machine tools is not only beneficial to meet the demandfor high performance machine of the domestic manufacturing industry, but also topromote the national industry status and the level of comprehensive national strengthof ascension, which have far-reaching strategic significance.This article aims to improve the reliability of domestic CNC vertical lathe, with6sets of a certain type of domestic vertical lathe as the research object, establish a set ofreliability prediction model based on fuzzy theory, using long-term collection ofreliability data obtained to get the reliability modeling on the lathe, and using basedon the weighted Euclidean distance of FMECA to the series of vertical lathe faultanalysis, in the end put forward in overall reliability growth measures for the CNCvertical lathe. The main contents are as follows：(1) This article first review the research current situation of the development andreliability of CNC machine tools at home and abroad. Then according to lowprecision of the traditional expert score prediction method in malpractices under thecondition of the lack of fault information, first proposed a new method of expectedCNC vertical lathe reliability based on fuzzy weighted geometric average model, andconstruct a solution model of subsystem fuzzy evaluation, uses the AHP method toweight experts, By qualitative method to remove fuzzy finally. The introduction ofthis new method will make the traditional method to be more perfect, Also create awider application field for reliability prediction.(2) Based on determining the reasonable test scheme, and through failure data tosort and preliminary analysis, choose the two parameter Weibull distribution toreliability modeling for the series of vertical lathe. Using the regression analysismethod to the undetermined parameters to solve, and then combined with the graphicmethod and K-S test method for hypothesis test to the established model, and finallywe make the series vertical lathe reliability related model.(3) In order to further understand the usability of the series of vertical lathe, thearticle uses the application of FMECA on vertical lathe fault analysis. First, useFMEA analysis on lathe machine and fault high-risk subsystem, so that we can masteron the whole grasp of the lathe failure condition, and fully consider the traditional riskpriority number in calculation common appears to offset each risk factor each otherand the amplification effect and other defects, establish a three-dimensional spacemodel of failure mode risk factors O, S, D and the RPN solving algorithm based onweighted Euclidean distance, so as we can obtain more accurate fai1ure Mode’s riskpriority number, and sort according to its value to each subsystem and determine theneed to improve the weak link.(4) On the basis of the above research contents, from the aspects of design,manufacture, use and maintenance of CNC vertical lathe put forward suggestions forimprovement as well as to the potential failure put forward prevention measures, forthe fault exclusion of the vertical lathe and other machine tool, and provide reference for reliability growth.