This paper discusses the results of the application of a method to optimize the quality characteristics and service life of products that degrade rather than fail in order to determine the warranty period of such products. The optimization method consists of the following steps: i) characterization of the problem; ii) planning and execution of experiments; iii) modeling of response variables; iv) optimization; and v) modeling of the product's service life and definition of its warranty period. The method involves the joint use of QFD (Quality Function Deployment), Experimental Design, and modeling of accelerated degradation tests through regression analysis. A new procedure is presented to determine and optimize the warranty period of products subject to degradation, based on the sensorial analysis of sample products to assess their level of degradation. The method is illustrated by a case study of the plastics industry, where the goal is to come up with a suitable warranty policy for plastic floor tiles in pigpens.
optimization; accelerated degradation tests; product lifetime modeling
