Integration Of Quality Control Tools and Mixed-Method Warehouse Layout Redesign for Return-Material Management at PT PLN UP3 Indramayu

Abstract

High defective rates in return-material management pose severe operational bottlenecks and financial losses in electric utility reverse logistics. This study addresses a critical defect rate averaging 10% (exceeding the 5% corporate limit) in returned Limiting and Measuring Devices (APP) at PT PLN (Persero) UP3 Indramayu. An integrative framework combining Quality Control (QC) tools and a Mixed-Method Warehouse Layout Redesign was developed to analysed defect root causes and eliminate material degradation. Defect prioritization via Pareto analysis and process capability assessment revealed that cable breakage (65.16%, 2.03 Sigma) and MCB casing damage (21.30%, 2.73 Sigma) were the primary defect contributors, performing significantly below industrial benchmarks. Root-cause identification using 5 Whys Analysis confirmed that floor stacking, static load overload, unstandardized handling, and mixed-storage practices directly accelerated physical damage. To resolve these issues, a mixed-method layout combining Dedicated Storage principles and a U-Shaped material flow was engineered. The proposed design features three-level heavy-duty racking, dedicated vertical space allocation, and a three-tier color-coded visual management system (Yellow for Receiving/Inspection, Green for Usable Main Storage, and Red for Scrap Isolation). This restructured flow enforces a strict First-In, First-Out (FIFO) mechanism, eliminates cross-movement, and mitigates material damage risk during reverse handling. The integrated approach provides a scalable practical framework for utility companies to optimize reverse logistics operations, reduce rework costs, and maintain inventory integrity.