Researches On Reliability Test And Reliability Growth Technology Of High-speed Punch

Pressure forming is an important metal forming process with some advantages such as high effective, high quality and low cost, which make it a wide range of applications in industry. With the development of industry and the increasingly fierce market competition, the requirement for working efficiency and forming precision of forming machine is higher and higher. This dissertation mainly carries on a systemic research on the key technologies and methods of reliability test&growth of high-speed punch, which include fault analysis, reliability accelerated degradation test design, reliability test platform development and reliability growth.According to the main characteristics and functions of a high-speed punch, fault mode and failure mechanisms are analyzed and the system is divided into nine function subsystems systematically based on the movement principle. And the fault criterion&including regulations, fault mode and fault code are determined. Based on failure data, the failure positions, failure mode, failure causes and failure cause classification are detailed statistical analyzed. Some failure mechanisms with higher failure rates of the high-speed punch are analyzed especially. In addition, the weakest links and potential shortcomings of the high-speed punch are pointed out.The reliability accelerated testing technology is described and the reliability accelerated degradation test technology is specially analyzed. According to characteristic of high speed punch machine, the reliability accelerated degradation test of the high speed punch is completed based on the reliability accelerated degradation testing technology. The accelerated stress and acceleration factor are determined based on the acceleration analysis. The performance degradation model based on Brownian motion with drift of the high-speed punch is built under the premises that the failure mechanisms of the high-speed punch should keep unchanged.A reliability test platform of main transmission system, which is the crucial subsystem of the high-speed punch, is designed to find the weakness part and improve the reliability growth of the high speed punch. First, the design requirements, functional requirements of the test platform are analyzed and test contents are determined. Then, taking the high speed punching machine as a fixed frame, the hardware reliability test platform is designed based on the idea of open architecture. Last, the software of the reliability test platform is designed by using virtual instrument technology. Based on the basic assumptions of reliability accelerated degradation test, the reliability accelerated degradation test of the high-speed punch is designed after discussions of many critical issues. The dynamic accuracy of bottom dead center, the amplitude of the body, vibration acceleration and noise of the high-speed punch are measured with the reliability test platform. The test results are analyzed and the feasibility of the reliability test platform is verified.According to the characteristics and functions of the high-speed punch, the reliability evaluation indexes are given. According to the failure data of the high-speed punch, the reliability indexes are computed. The reliability growth management of the high-speed punch is analyzed and the reliability growth process is given. The improvement measures for reliability growth are drawn based on the analysis of different stage in the life cycle of the high-speed punch. The reliability growth technology based on finite element analysis is analyzed in the design stage. The improvement measures of manufacturing process, quality assurance analysis of key supporting parts and the assembly quality are given in manufacture stage. The improvement measures of the primary weak link with higher failure rates based on the failure analysis are given in usage stage. The MTBF of ameliorated high-speed punch is improved by25.4%with the practical application.