Quality Control Analysis to Reduce Rejects in Plastic Seal Manufacturing
DOI:
https://doi.org/10.54099/ijibr.v4i2.1513Keywords:
Quality Control, SPC, Fishbone Diagram, Process Capability, Rejects, Plastic SealAbstract
Purpose – This study aims to identify the root causes of product rejects and evaluate the effectiveness of quality control improvements at PT Karya Gemilang Indonusa, a plastic seal manufacturing company.
Methodology – The methodology used includes Statistical Process Control (SPC), especially p-chart to monitor defect proportion, and Fishbone Diagram for root cause analysis. Data were collected from production reports between January and December 2024 and after improvements in January–April 2025.
Findings – The study revealed that flashing and short mold are the dominant defects, accounting for more than 55% of total rejects. After corrective actions such as operator training, machine maintenance, and parameter adjustments, the reject rate reduced from 12.91% to 4.48%, and the process capability index (Cpk) improved from 0.333 to 0.667.
Novelty – The integration of SPC and Fishbone Diagram in a real-world manufacturing setting effectively reduced rejects and increased process stability, supporting sustainable production.
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