Reliability Analysis Of An Automatic Tool Change Manipulator

An important feature of machining center, automatic tool changing manipulator is a key component to realize the automatic tool change function. Its mechanism reliability levels are in relation to the level of reliability of a machining center. Undertaking the important task to change tools at any time during the work, the manipulator will directly affect the operation and use of machining center.First, the background of the reliability research of the automatic tool changing manipulator, the progress of the relevant researches of the world and the general information of this research were introduced. Besides, research on the reliability of CNC machine tool components is also briefly introduced in this article.Second, the failure issue of the deployment mechanism of the automatic tool change manipulator was analyzed with FMECA. FMEA and CA were completed, and the report of FMECA for the automatic tool change manipulator was presented. According to the analysis, the list of the key parts was presented. And the Ⅰ, Ⅱ faults of the automatic tool change manipulator were classified according to the severity and the criticality.Third, the system of the automatic tool change manipulator was analyzed with FTA. By comparison, we can find that FMECA is good at describing the effect of the component failures on the system; while FTA is good at finding all possible initiating faults and representing the reliability of the system. The combined analyses are clearer and more reasonable to reveal the relationship between component failures and system failure.Fourth, the reliability analysis of the tool-holding mechanism and the kinematic analysis of the tool-holding mechanism of the manipulator were completed. ADAMS parametric simulation model was built, and ADAMS command was compiled to implement the simulation program. The method of Monte Carlo was used to randomly change the variables. The results were analysised to get the influence of dimension error on the manipulator reliability.Finally, the reliability issue of automatic tool change manipulator was analyzed. The system reliability models of the automatic tool change manipulator under the normal conditions were built. Then, the methods of reliability allocation for the automatic tool change manipulator were studied. And the reliability of every component of the automatic tool change manipulator was allocated with the methods of the integrated evaluation allocation and the equal allocation according to the structural characteristic of the automatic tool change manipulator.