Reliability Assessment Of Air-conditioner And Its Warranty Optimization Based On After-sales Fault Data

With after-sales fault data applying to reliability assessment and warranty design, the cost of reliability research can be reduced significantly and the potential of product quality improvement can be fully excavated.Firstly, by analysis process such as clustering analysis for the climatic zones of China, the definition of failure criterion and service time compression, problems with air-conditioner such as different working condition and natural environment, functions seasonal routine work, no record of specific working time which led to service time and actual working hours exists conversion ratio are solved. In this way, grouped multiple truncate data sub-sample which is suitable for reliability assessment is acquired from after-sales fault data.Secondly, the MLE of exponential distribution and the reliability assessment theory for imprecise working time contrast to verify reasonable of data processing. At the same time, the reliability model of air-conditioner is acquired. The reliability assessment results of a certain type of air-conditioner show that methods of the data processing and the reliability assessment can effectively be applied to reliability assessment of air-conditioner.Finally, for the reliability growth of air-conditioner in the manufacture and use process, the AMSAA model is applied to describe the reliability growth between batches of the generation product. Parameters of AMSAA model are estimated by after-sales fault data from batches of the earlier generation. Then the reliability of the new generation products can be calculated. The warranty period optimization model is established to design the optimal warranty period of air-conditioner. The model’s objective function is composed by the exponential warranty benefit function and the linear warranty expense function. After-sales maintenance cost is the constraint condition. Through the example analysis of a certain type of air-conditioner, the method of warranty period optimization design based on the reliability growth is verified feasible. Compare with the past warranty period design method, the product warranty period can be lengthened.