Research On Environmental Worthiness Technology Of CNC Punch Press

As important basic manufacturing equipment, computer numerical control machinetools are widely used in manufacturing industry and playing a tremendous role in it. Itstechnical level directly determines the development and competitiveness ofmanufacturing industry. In recent years, though the performance evaluation of domesticCNC machine tools has definite promotion, there is still a huge gap compared withinternational advanced levels in reliability and environmental worthiness. High failurerate and poor environmental worthiness have become the bottlenecks which restrict thedevelopment of domestic CNC machine tools. By several years researching, reliabilityof machine tools has an obvious promotion. Nevertheless, because of poorenvironmental worthiness or severe operation environment, machine tools hardly workunder provided environment, so their reliability can’t be guaranteed. In this paper,environmental worthiness of one kind CNC punch press is researched. By analysisevaluation work, a series of guarantee technologies of machine tools environmentalworthiness are put forward, providing new thinking and methods for qualityimprovements of CNC punch press.At first, fault data and application environment of machine tools is analyzed. Beginwith the analysis of failure data, the current machine fault information statistical isclassified. Based on reliability index calculation, the operation reliability level ofresearch object is confirmed. And then, by decomposition of running environmentfactors, we can find out the influence mechanisms of various environmental factors onthe machine tools. Based on former analysis, environmental impact fault tree isstructured, with various environmental factors at the bottom, induced ways ofenvironmental factors to important failures are obtained.Then, environmental worthiness evaluation work is carried out. This paperintroduces the commonly used equipment environment evaluation method, bycomparing the advantages and disadvantages of various methods, we use fuzzycomprehensive evaluation to evaluate the environmental worthiness level of machinetools. The evaluate results are presented by environmental impact degree. First carryingon the influence evaluation of the single environmental factor, fuzzy evaluation resultsare obtained. Then using analytic hierarchy to get weight vectors of two levelenvironmental factors, after fuzzy arithmetic, final evaluation results are worked out. That is the impact degree of overall environment factors on the machine tools. Secondstep is to evaluate the environmental worthiness of subsystems. Based on FMECAresults, we can calculate the environmental impact degrees of constitutional units ofsubsystems. After sorting we can find out the environmental impact weak links ofcertain subsystem. The evaluate results can guide design improvement and maintenancestrategy.Finally, the CNC punch press environmental worthiness security system is putforward, including four aspects. Firstly, the environmental worthiness design principlesand design methods are introduced, fundamentally improving the environmentalworthiness performance of machine tools. Secondly, by conducting environmentaltesting, the cutting test process, test conditions and test sequence arrangement aredetailed analyzed. In terms of purchased parts acceptance, environmental stressscreening measures are put forward. Stress combinations of temperature circulation andrandom vibration playing an important role in the early fault elimination of electroniccomponents, can obviously increase the environmental worthiness of the purchasedcomponents. At last, for operation environment control, the introduction of operationparameters on-line detection and compulsory maintenance thoughts, real time to ensurethat the machine using environment conditions complied with the requirement ofreliability.