Risk Reduction in Modified Sewing Machinery for Automotive Wire Harness Production Using JSA and ISO 12100

Abstract

Machinery modification in industrial manufacturing processes may improve production efficiency and reduce operational costs; however, the absence of systematic risk assessment may increase occupational hazards among workers. This study aimed to identify hazards, assess risk levels, and evaluate the effectiveness of risk control measures in the apron-sewing process of automotive wire harness production by integrating Job Safety Analysis (JSA) with the ISO 12100 framework. This developmental research involved work process analysis, hazard identification, and pre- and post-improvement risk assessment using a risk matrix approach. Control measures included the design and installation of fixed machine guards at critical hazardous points, together with safety training and safety communication measures. The results showed that the process consisted of eight operational steps. Before improvement, two steps (25.0%) were classified as very high risk, particularly workpiece positioning and machine sewing operations (R = 12). After implementation of the control measures, the risk score decreased to a moderate level (R = 6), representing a 50.0% reduction, and no high- or very high-risk steps remained. The findings indicate that integrating JSA with ISO 12100 improves the comprehensiveness of machinery risk assessment, while engineering controls combined with administrative measures can effectively reduce machinery-related occupational risks in practice.