CNC lathe factory introduction to four indicators of nc machine tool reliability
CNC lathe factory introduction to the reliability of nc machine tool four indicators released time: 2016 - 05 - 30 clicks: 1, 2333 times the average trouble-free time interval average trouble-free time interval MTBF ( MeanTimeBetweenFailures) Refers to repairable product, the average of the adjacent fault work time, is important index to measure the reliability of the concrete numerical value given in the product standard. According to statistics, CNC system minimum acceptable MTBF should not be less than 3000 h. Statistical data show that foreign numerical control system of MTBF for 5000 h and 22000 h. For reliability assessment, the main is trouble-free parameters. The function of the CNC system loss provisions called failure. The average trouble-free working time accurately reflect nc equipment normal working time. It refers to a single fault happens, until the next trouble-free clearance work before failure time average. Nc machine tools after early wear stage, eliminates the early failure, entered the stage of normal work, the basic control work in occasional failure phase, can be thought of as the time between failures to obey exponential distribution. Nc machine tool failure interval time interval estimation of the general level of 1 - take a confidence interval α = 90%, that is, the probability of true value falls within the range of estimates of 90%. Evaluation according to the numerical control machine tool failure occurs when the number of times and the relevant time, then can be calculated according to the above formula. The longer the MTBF said the higher reliability, the stronger the ability to work correctly. 2, mean time to repair (mean time to repair MeanTimeToRepair) Also known as the average maintenance time, from find fault to the average of the machine tool repair time required to restore regulation performance, referred to as 'MTTR. It includes necessary to confirm the failure happened time and maintenance time, time to get accessories, maintenance team's response time, a time, and record all the task will devices to be put into use. MTTP and not only the product itself design related, and the level of usage, maintenance, spare parts strategy are closely related. 3, the inherent availability inherent availability (also called effective degrees 可用性) , it is under the specified conditions of use, mechanical equipment and spare parts to keep the probability of its regulation function, referred to as A. Effectiveness is an important index for evaluation of equipment utilization, and is also the important factor of equipment production capacity directly. Effectiveness is a function of time, usually mention effectiveness refers to the time t be & infin; Instantaneous effective degrees, it is the numerical control machine tool average trouble-free working time relative to the MTBF and mean time to repair and ratio, which in a certain observation period, the product can work time for work and can work more than the sum of the time. 4 hold time, precision and accuracy of holding time, kT） Is duty and nc machine tools in two class under the condition of abiding by the rules of use, its precision in machine tool accuracy within the prescribed scope of the standard time. The observed value based on the prototype of keep the precision of the shortest time of a machine tool accuracy hold time shall prevail. Above four evaluation indexes, the MTBF focused on nc lathe trouble-free sex, is the most commonly used evaluation indicator; MTTR reflected the maintainability of nc machine tool, that is, the ease of maintenance; The inherent availability of A comprehensive reflect trouble-free and maintainability, namely effectiveness; Hold time reflects the durability of nc machine tool accuracy and reliable life.