Analysis of Dimensional Nonconformities During IQC Inspection of M12–RJ45 Ethernet Cable Assembly Using Root Cause Analysis

Abstract

Abstract—Recurring Dimensional Out-of-Specification (DoS) findings were identified during Incoming Quality Control (IQC) inspection of the M12–RJ45 Ethernet Cable Assembly at PT PCI Elektronik Internasional. This study aims to identify the causes of recurring dimensional nonconformities using Root Cause Analysis (RCA) and a Fishbone Diagram. Data were collected from IQC inspection records, dimensional measurement results, engineering drawings, customer specifications, and direct observations over a two-month period. The results identified two main findings: recurring dimensional nonconformities across incoming lots and a discrepancy between the existing engineering drawing and the latest customer-approved specification. RCA verification showed that the Method factor was the main contributor, particularly the absence of a standardized Work Instruction (WI), unclear measurement positioning, and incomplete engineering drawing revision. Insufficient understanding of measurement positioning and locking ring position variation were identified as supporting contributors, while Machine and Environment were not identified as contributors. Three improvement actions were proposed, with the development of a standardized WI selected as the primary recommendation to improve measurement consistency and reduce recurring dimensional nonconformities during IQC inspection.