<![CDATA[Injection molding is a widely used manufacturing process in the plastics industry because of its high production efficiency and ability to produce components with high precision. However, defects such as burn marks may occur and affect product quality. Burn marks are characterized by surface discoloration caused by thermal degradation of polymer materials or trapped gases within the mold cavity. This defect reduces product quality and increases rejection rates, particularly in polypropylene products. This study aims to analyze the factors influencing burn mark defects using the Ishikawa diagram approach, which classifies causes into human, machine, method, material, and environmental factors. We conducted experimental tests by varying nozzle temperatures from 225°C to 250°C and injection speeds from 60.8 mm/s to 67.2 mm/s, with each condition repeated three times. The results indicate that higher temperatures increase the likelihood of burn mark defects. The optimal condition was obtained at 225°C with an injection speed of 67.2 mm/s, producing defect-free products. In contrast, the most severe defects occurred at 250°C with an injection speed of 60.8 mm/s. These findings highlight the importance of proper parameter control to improve product quality in injection molding processes.]]>
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