A New Model For Traceability Evaluation based on Costs-Benefits Analysis FMECA Principles and Fuzzy Sets Techniques

Quality Certification according to ISO9000 standards requires that firms have to be able to track every jobs, assembling steps, and equipment needful to realize each product. Another aspect of a traceability system is the possibility, for each type of product, to locate on the market every delivered ones on which analysis and/or corrective actions has to be made, due to an unconformity found on a certain component or on a certain job (customer-oriented traceability). This last feature can give real advantages in terms of customer satisfaction, safety and firm image, therefore its establishment is often related to high costs due to the startup of dedicated procedures for parts identification, information systems, human resources, etc. The best choice, in this case is to submit to this type of traceability procedure a set of components that, from an analysis of the bill of materials, are recognized as critical in terms of certain critical parameters such as safety, cost, product functionality, etc. In this paper we wish to give a practical decision supporting tool useful to identify, for an industrial product, which specific components have to be traced. In our prototype system the well known cost benefits analysis, FMECA principles and Fuzzy Sets techniques have been implemented in a structured approach to define, inside the bill of materials, which components have to be submitted to the traceability procedure. 1. Structure of the system Our approach is structured according to three sequential steps. The first one is related to the development of a specific procedure, based on a cost/benefits analysis of the Bill of Materials (BoM) for the determination of the minimum number of parts to be traced (Critical number). The second step is related to the definition, according to FMECA principles, of a Criticality index for each part of the product, while to define the specific parts to be traced (Critical set) a system based on Fuzzy Sets theory has been developed. The three main steps in which the proposed system has been conceived and developed can be summarized as follows: 1. Cost/benefits analysis for the BoM, finalized to the determination of the minimum number of parts to be traced (Critical number Cn); 2. Implementation of FMECA principles for the BoM oriented to the definition of a Criticality Index Ic that has to be able to give a measure of part criticality with respect to the traceability; 3. Fuzzy Sets-based approach for the identification of the parts to trace (Critical set Ix) on the basis of the values of Ic and Cn related to the BoM. 1.1 Cost-Benefits Analysis applied to Traceability: The model