Research On Reliability Growth Of Disc-type Tool Magazine And Msnipulator

Disc-type tool magazine and manipulator is an important functional componentof vertical processing center, it is compose of tool magazine, indexing devices of toolmagazine, pneumatic devices, manipulator, manipulator’s actuator, electrical devices,positioning and clamping devices, drive unit, lubrication devices etc. This makes thedisc-type tool magazine and manipulator become a typical mechatronic product. Thedisc-type tool magazine and manipulator can automatic choose and change tool fastlyand reliably, which realize the vertical processing center’s multi-process and even allmachining processes though one fixture, reducing non-cutting time of processing andimproving production efficiency, thereby greatly reduce the manufacturing cost ofeach part. Therefore, whether the complex disc-type tool magazine and manipulatorcan ensure accurate and reliable tool change action or not is one of the key issues ofvertical machining center. Hence, this paper is going to research on the reliabilitygrowth of the disc-type tool magazine and manipulator, which is rely on “High-endCNC machine tools and basic manufacturing equipment” the national science andtechnology major projects--the reliability design and testing techniques of keyfunctional components (2010ZX04014-011).According to the structure, working principle and function of the disc-type toolmagazine and manipulator, this paper first determines the fault criterion and explicitfault transmission relationship of the disc-type tool magazine and manipulator, whichcould direct us to collect the fault information. Second, this paper makes use of fuzzyFMECA analysis method to analyze the disc-type tool magazine and manipulator’sfault information. Fuzzy hierarchy analysis, which considers the objective andsubjective factors, is proposed to calculate the weight of three decision-making factors:failure mode frequency, failure rate and failure impact of fuzzy FMECA analysismethod to solve the expertise’s subjective empowerment. Further more，the grayrelational analysis method is delivered to analyze the failure mode, which has thesame hazard，to get a more detailed order. According to the analysis result, we canidentify the disc-type tool magazine and manipulator’s weak link; which can direct usto take target reliability growth measures from the involved manufacturing, assembly,purchased parts and the use of the disc-type tool magazine and manipulator’s weakposition and large hazard failure mode. Further more, this paper delivers the improvement of the tool magazine and manipulator’s reliability design suggestion,which might improve the reliability of the tool magazine and manipulator.Finally, according to the reliability criterion and combined with the factorypractical, the basic performance reliability experiment program and key componentreliability experiment program is designed, and put the key component reliabilityexperiment program into use to verify the effectiveness of the reliability growthmeasures and the improved reliability design suggestions. The reliability experimentverified that when we put the reliability growth measures and the improved reliabilitydesign suggestions into use, the average failure rate of the disc-type tool magazineand manipulator has been effectively reduced, which is reduced5.37percent.Therefore, the reliability growth measures and the reliability designsuggestions are effective, which can effectively promote the reliability growth of thedisc-type tool magazine and manipulator.