Field reliability estimation through the Systemability function: a case study in the household appliances

Purpose: One of the most challenging issue for a product manager of a manufacturing company is to assess the product reliability performances during its entire life cycle, starting from the product launch until its obsolesces, taking into account all the possible issues of a modern product-process systems. Considering the classical approach reliability estimation requires historical data or the implementation of experimental tests on the product. Frequently, the reliability estimation, coming from experimental test (in house) are different from those obtained by the analysis of the service data (in field). The former are executed in laboratory with standardized, controlled and repeatable conditions, while the latter are affected by random environmental and operating conditions. The aim of the study is to identify a correlation model between in house and in field reliability performance for an household appliances. Design/methodology/approach: A literature review shows how the best correlation model, that at the moment is available for this type of application, is the Systemability function proposed by Pham. This model is based on the definition of the difference between in house and in field conditions by some parameters that represent the random environmental influence. The analysis was conducted on the life cycle data of the same washing machine model relative to two different production years. Moreover two different European country’s market were considered separately. Data relative to the first year were used to calculate the in-field and in house reliability performances and to define the correlation function Systemability. The data, coming from the second year, were used, together with the environmental parameters defined by the already calculated Systemability function, to perform a forecast of the in-field product reliability performance and consequently in order to validate the model. Originality/value: This paper presents an application of the Systemability model applied on an industrial product such as a domestic washing machine. The use of field data that come from two different European markets (relating to the same product) can be considered a great opportunity to validate the correlation model. In fact, it is possible to investigate the effects of two different environmental condition sets (costumer behavior, market issue, logistics, etc) on the reliability performances of a product population that has been manufactured in the same industrial plant. One of the most important outcomes of the Systemability model was the capacity to predicts two different in field reliability performances relative to two different markets in contrast with the classic methodology that uses the same in house reliability data without considering environmental effects. Certainly a correct estimation of the in-field reliability can be very useful to design all the product service activities and to assess the product quality.