Reducing The Defect (Not Good) Rate to Improve Production Efficiency Using DMAIC: A Case Study of an Automotive Seat Cover Manufacturer
DOI:
10.47353/ecbis.v4i6.482Published:
2026-09-10Downloads
Abstract
This study addresses a persistent quality problem at PT SSC, a second-tier automotive seat cover manufacturer in Indonesia, where the defect ratebreferred to internally as the Not Good (NG) rate for embossed leather and PVC products remained above the internal 2% target during July–December 2025, causing excess material consumption and reduced profitability. The study aims to identify the main factors causing the NG rate to exceed the threshold and to formulate strategies that reduce it and enhance production efficiency using the DMAIC framework. Drawing on internal production records and semi-structured interviews, the data were analyzed through Pareto analysis, Statistical Process Control (U-Chart), Fishbone analysis, and the Borda Count. The results show that the sewing process is the dominant NG contributor (76% for leather and 67% for PVC) and is statistically out of control, with two prioritized root causes which are the absence of a structured preventive maintenance schedule and the absence of a standardized pre-OJT operator training program. Accordingly, the study proposes an implementation plan combining a Preventive Maintenance Program and a Structured Operator Training Program, reinforced by a real-time monitoring dashboard and a re-evaluation protocol. Grounded in the company’s own data, the projection indicates that the average NG rate can approach the 2% target and profitability can recover to about 85% of the expected margin. The study contributes an evidence-based, implementation-ready improvement roadmap for a sewing-intensive automotive component context that remains underrepresented in the DMAIC literature
Keywords:
Defect reduction DMAIC Production efficiency Root Cause Analysis Statistical process controlReferences
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