Research On Reliability Test Technology Of Horizontal Machining Center

Numerical control machine tools as important basic equipment with high contentof technology are being widely used in manufacturing industry and playing atremendous role in it. Its technical level directly influence and to some degree determinethe development and competitiveness of manufacturing industry. China is a strongcountry in manufacturing, so the demand of machine tools is huge. But domestic CNCmachine tools are mainly confined to low-and-middle products, which mean high-endCNC machine tools are highly dependent on imports. It seriously restricts thedevelopment of manufacturing and national defense industry. In the past20years, manyresearchers were engaged in tackling the key problems about CNC machine tools, andthey has boost many performance terms of machine tools, while there is still a huge gapbetween domestic CNC machine tools and imports in reliability level. So the situationthat high-end NC products are mainly dependent on imports did not change at all. Highfailure rate and the low reliability have become the bottleneck which constrains thedevelopment of China-made machine tool industry. Improving the reliability level ofdomestic machine tools has already become the urgent task to revive of the equipmentand manufacturing industry.This paper is supported by many projects from High-grade NC Machine Tools andBasic Manufacturing Equipment National Science and Technology Major Projects. Theresearch object of this paper is a certain series domestic horizontal machining toolcenter, whose fault spectrums and failure mechanisms have been thoroughly andsystematically studied. The work condition spectrum and load spectrum of horizontalmachining tool center were built based on processing technology data as well. All thisabove have provide the scientific evidence for key functional component and the wholemachine tool reliability test. In this paper, the reliability test schemes of automatic toolchanger and the whole machine were exploratively put forward, and some improvementmeasures were proposed after analyses of testing results.The main work and contribution of this paper is as follow:①The Analysis of Horizontal Machining Tool Center Fault Spectrums and theFailure MechanismsThrough the collection and analyses of filed failure data of domestic horizontalmachining tool center, the fault spectrums of functional parts and the whole machine were obtained respectively. Weakness and main influencing factors of machining toolcenter were found out after the thorough and systematical analysis of failuremechanisms, and they also provided the theoretical foundation for choosing the testobject and the kinds of load.②Research on The Work Condition Spectrum And Load Spectrum of HorizontalMachining CenterBased on the statistical analysis of a large amount of processing data from typicalusers, the work condition spectrum and load spectrum of horizontal machining toolcenter were obtained, including spindle speed spectrum, exchanging frequencyspectrum of ATC and TAED (Tray Automatic Exchanging Device), load spectrum ofNC rotary table, cutting force spectrum, which could be considered as scientificevidences of reliability test schemes of horizontal machining tool center.③Research on The Reliability Test Technology of ATCThe working principle and structure of ATC were introduced at first, and reliabilityenhancement testing scheme of ATC were proposed according to the fault spectrum andload spectrum. Meanwhile the reliability test platform of ATC was designed for the test.Some improving measures were put forward after analyses of testing results.④Research on The Reliability Test Technology of Machining Tool CenterAccording the theory of machining tool center failure rate bath curve, the time ofreliability test on machining tool center was figured out. The reliability testing schemeof the whole machine included three parts: simulative cutting test, cutting test, andspindle loading test. Through the test, some early failures of machining tools wereexposed. After analyses of faults, some corrective actions were implemented.