Method of Calibration Period Determination for Temperature Chamber based on Risk Analysis

The temperature box is the main equipment for temperature testing, and its accuracy affects the quality and credibility of the test results. Currently, temperature chambers are calibrated regularly, but too long a calibration period will result in too high calibration risk, and too short a calibration period will result in too high calibration costs. In order to formulate a scientific and reasonable calibration cycle and provide a theoretical basis, the following formulating methods are proposed. First, a combination forecasting model that integrates similar product information is proposed, in which GM(1,1) is used for overall prediction, Markov model is used for residual prediction, combined weighting is used to obtain the prediction sequence of calibration data, and the specific temperature box is calculated with the same kind The Euclid distance between temperature boxes is based on the similarity function to determine the specific temperature box prediction model to predict the drift trend of performance parameters in the next calibration cycle; secondly, the probability density function and reliability model of the calibration parameters are used to establish the reliability function in a certain period, consider the aging of the temperature box, combine the actual use time and the number of calibration cycles to establish a hybrid failure rate evolution model, and derive the reliability function in the prediction period based on the existing reliability function and failure rate, The specific change time of the calibration cycle is refined according to the reliability function; finally, the validity of the proposed strategy is verified according to the case analysis.