APPLICATION OF FAILURE MODES AND EFFECTS ANALYSIS (FMEA) FOR QUALITY IMPROVEMENT IN SPUR GEAR MANUFACTURING PROCESS: A CASE STUDY

Abstract

The spur gear industry in Pakistan is beset with serious operating problems, especially the failure of the gears during manufacturing without notice, resulting in substantial rejection rates, expensive rework, and unreliable product quality. Failure Mode and Effects Analysis (FMEA) has been used widely in various industries, including automotive and mechanical assembly industries, but there is limited empirical literature on the systematic use of FMEA in the micro level manufacturing stages of spur gear production in a developing industrial environment. The present study proposes comprehensive PFMEA (Process FMEA) case study to overcome this, using the Delphi technique to combine experts' knowledge and systematically identify, categorize and quantify operational risks of each of eight manufacturing processes for Waseem Brothers Gear Industry, Gujranwala, Pakistan. Potential failures were assessed by Severity (S), Occurrence (O), and Detection (D) rankings and Risk Prioritization Numbers (RPNs) were calculated. Before intervention, the most important risk factors identified were: gear cutting (RPN = 240), heat treatment (RPN = 140) and raw material storage corrosion (RPN = 75). All the RPN values after implementing the targeted corrective actions were kept below the threshold of 70, which was achieved by optimizing the lubrication regimes, controlled thermal dwelling parameters, ventilated storage covers and high-performance tool sharpening. The proposed framework offers some practical and cost-effective ways for spur gear manufacturers to mitigate risk in their operations to maximize operational efficiency and improve quality management.