<![CDATA[General Background Optimizing work productivity is essential for manufacturing companies to maintain operational efficiency and market competitiveness. Specific Background In commercial production lines at PT. XYZ, fluctuations in cycle times and instances of overtime indicate underlying operational inefficiencies that require immediate identification. Knowledge Gap However, detailed empirical evaluations combining systematic cycle time measurements with root-cause analysis for specific heat exchanger commercial assemblies remain limited. Aims This study aims to analyze and evaluate the productivity level on the commercial line at PT. XYZ using time study measurements and fishbone diagram approaches to propose targeted operational improvements. Results The results demonstrate that commercial line productivity is suboptimal, characterized by frequent overtime and uneven operator allocation across stations, alongside specific constraints such as part quality issues, excessive oil consumption, and material supply shortages. Novelty This work provides a comprehensive diagnostic framework by mapping stopwatch time study indices directly against multi-factor fishbone categorizations for manufacturing bottlenecks. Implications The findings offer actionable strategies for industrial management to balance workloads, optimize operator counts, and mitigate production delays. Key Findings Highlights Commercial line productivity is suboptimal, showing frequent overtime and uneven operator distribution across manufacturing stations. Stopwatch time study calculations reveal significant workflow variances, with many workstations experiencing low productivity indexes and time overruns. Root-cause evaluations identify material quality defects, excessive oil consumption, and supply shortages as primary contributors to production delays. Keywords Productivity, Time Study, Fishbone Diagram]]>
