Reliability Evaluation And Management Of C××××Double Column Vertical Lathe

Heavy machine tools play an important role in the defense industry, aerospace,transportation, energy and other national key industries; however, the low reliability ofthe domestic heavy machine tools restricts its market competitiveness and market share.Therefore, carrying out the reliability research of domestic heavy machine tools has astrong practical significance.According to the structural characteristics of the C××××double column verticallathe, the reliable model of vertical lathe of the type is established; the field testspecification is developed. The field fault data of twenty-five vertical lathes of the type iscollected, base on the fault data, the fault analysis and reliability evaluation wereanalyzed.The fault positions,fault mode,fault causes and causes for classification of theentire lathe were analyzed by Fault Mode and Effects Analysis method. The faultpositions, fault mode and fault causes of weak subsystems, which have a greater impacton the entire lathe, were analyzed deeply. The subsystems'degree of criticality iscalculated quantitatively by Criticality Analysis method. Through faults analysis, theweak reliability links of vertical lathe of the type are founded, which provide the basis forthe reliability improvement.The fault tree of "guide surface of rotary table be injured" is established. All theminimal cut sets of the fault tree are founded. The fuzzy probability distribution of thebasic events are expressed with the triangular fuzzy number, the probability distributionof the top event and the fuzzy important degree of bottom events are calculated. Throughanalyze, the weak reliability links of the fault tree and the reliability improvementpriority are determined.It is proved that the time between faults of vertical lathe of the type follows Weibulldistribution. The value of Mean Time Between Faults, Mean Time To Repair andAvailability are calculated. So the reliability level of vertical lathe of the type is evaluatedquantitatively. From the perspective of reliability management, combined the exposed weakreliability links in the fault analysis, measures which were to improve the reliability,included the exclusion of early faults, the reliability improved design, the key workingprocedure, the key assemble and debug process, the key components and outsourcingparts were proposed. The thesis provides a reference to faults exclusion, manufacturingand assembly quality improvement and so on for vertical lathes of the type and othermachine tools.