Risk Priority Number vs Action Priority in Electrical Systems

FMEA (Failure Mode and Effect Analysis) is an important tool in evaluating a product or service either before it is made or prior to its market placing. Its purpose is to reduce any subsequent expenses due to defects. The principle of this tool says that it is cheaper to prevent than to repair. In the automotive industry, FMEA is widely implemented, but there is a clearer trend in recent years to move from Risk Priority Number (RPN) analysis to Action Priority (AP) one. The aim of this paper is to present a comparative analysis between FMEA using RPN and AP, respectively. Consequently, we started from an FMEA made for Electronic Stability Control (ESC) which is more and more present on today's cars. The obtained results clearly indicate the lack of an integrative approach to the two evaluation modalities starting from the RPN determination, but the action plan being correlated with the AP.

Introduction

Failure Mode and Effect Analysis (FMEA) was first performed in aerospace industry more than 60 years ago. This domain always focused on safety issues. Chemical process industry adopted this tool in the following years. From the beginning, the goal of FMEA was and still remains the prevention of accidents and incidents [1]. In every engineering field, FMEA was implemented and in the last decades the automotive industry transposes it as a quality improvement tool. The FMEA represents a systematic series of activities aimed at recognizing and evaluating the potential failure of a process / product and its effects, followed by identifying the actions that would lead to eliminating / reducing the chance of failure [2, 3]. The purpose of FMEA is preventing product and process problems before they occur. The result is a stronger process, because the need for after occurrence corrective action and overdue change crises are eliminated or at least reduced [1].