Modelling And Optimization Of Inspection And Warranty Based On Delay Time

As the market becomes more competitive,manufacturers often offer warranties in order to attract and retain more customers.Therefore,reducing the cost of warranty service is crucial for manufacturers.The common way to reduce the cost of warranty service is to make reasonable decisions on product warranty and maintenance strategy.Based on the theory of delay time,this paper carries out the modeling and optimization of testing warranty,and carries out the research in the following three aspects.(1)Based on the concept of three-stage failure process,this paper constructs a periodic inspection and preventive replacement model for renewable warranty products,and carries out optimization analysis.The manufacturer inspects the product at equal intervals during the warranty period until minor defects are found.When the product is detected to be in minor defective state,the subsequent inspection interval is shortened by half.If the product is found to be severe defective state or failure,it shall be replaced immediately and the warranty period shall be updated.From the manufacturer's perspective,the average warranty cost per unit time should be considered and minimized to optimize the inspection interval.(2)Based on the concept of two-stage failure process,the model and optimization of periodic inspection and preventive replacement of renewable warranty products with remaining warranty threshold are carried out.The product warranty period is divided into two stages: from the start of the operation of the product to the remaining warranty period is equal to the threshold stage is recorded as the inspection and replacement period;The minimum maintenance period is recorded from the remaining warranty period equal to the threshold value to the end of the warranty period.During the inspection and replacement period,the manufacturer shall carry out periodic inspection at equal intervals.If the inspection finds that the product is in a defective state or fails,the product will be replaced immediately.In the minimum maintenance period,in order to reduce the service cost,the manufacturer does not implement inspection and replacement,and only carries out the minimum maintenance for the failure.Consider the average warranty cost per unit time from the manufacturer's perspective and minimize it to optimize thresholds and inspection intervals.(3)Based on the two-stage concept of failure process,non-renewal maintenance products that can be repaired are modeled and optimized for non-renewal maintenance inspection and preventive maintenance with remaining warranty threshold.The product warranty period is divided into two stages: the period from the start of the product operation to the period when the remaining warranty period is equal to the threshold is recorded as the inspection and preventive maintenance period,and the period from the period when the remaining warranty period is equal to the threshold to the end of the warranty period is recorded as the minimum maintenance period.During the inspection and preventive maintenance period,the manufacturer conducts periodic inspection.If the product is found to be in defective state or failure,the manufacturer will not replace it,but carry out preventive maintenance to reduce the warranty cost.During the minimum maintenance period,only minimal maintenance is performed for failures that occur.Considering the average warranty cost in the warranty period from the manufacturer's point of view,the optimization inspection interval,threshold and preventive maintenance level are obtained.This paper studies the modeling and optimization of inspection based on delay time,enriches and expands the warranty model based on state maintenance,and provides a basis for inspection and preventive maintenance warranty.