数控机床可靠性加速试验与评估研究

Research on Accelerated Reliability Test and Evaluation of CNC Machine Tools

针对数控机床可靠性快速测评技术研究不足、行业内缺少相应的可靠性快速测评方法的问题,提出一种基于修正应力的逆幂律模型评估方法。首先,应用AHP方法建立加速应力层次修正结构对加速应力进行修正;其次,基于修正应力的加速模型确定了试验的总体试验方案、流程、剖面以及数据采集方式,并采用修正应力对逆幂律模型进行求解;最后,在某型号国产数控弯管机上开展可靠性加速测评试验。对试验数据中的加速应力应用该方法进行修正并与同型号设备跟踪统计常规试验结果对比,威布尔形状参数的相对误差由7.5%降低至4.7%,MTBF点估计值得相对误差由16.9%降低至5.9%,验证了本测评方法的可行性和准确性。

Considering insufficient research on the rapid reliability evaluation technology of CNC machine tools and the lack of corresponding rapid reliability evaluation methods in the industry,an inverse power-law model evaluation method using corrected stress is proposed.First,the AHP method is used to establish the hierarchical correction structure of accelerated stress for accelerated stress correction.Second,based on the accelerated model of modified stress,the overall test scheme,process,profile,and data acquisition method are determined,and the modified stress is utilized to solve the inverse power-law model;Finally,the reliability accelerated evaluation test on a domestic CNC tube bending machine is conducted.Apply this method to correct the accelerated stress in the experimental data,and compare the results obtained with the conventional test results of tracking statistics for the same type of equipment,the relative error of Weibull shape parameters value is reduced from 7.5%to 4.7%,and the relative error of MTBF value is reduced from 16.9%to 5.9%,which verifies the feasibility and accuracy of our evaluation method.