Productivity is a mindset focused on progress and continuous improvement, encompassing efficiency and effectiveness in production processes. In the piston industry, effective machinery and maintenance are crucial to meet market demands and maintain product quality. This study evaluates the Overall Equipment Effectiveness (OEE) of machining line 2 at PT XYZ, a piston manufacturer, identifying factors affecting effectiveness and recommending improvements. The research calculates OEE, including availability, performance, and quality rates, and analyzes the Six Big Losses to pinpoint major inefficiencies. Data from January to December 2023 were used, applying Pareto and Fishbone diagrams to identify the root causes of losses. The average OEE for line 2 was 72.43%, below the Japan Institute of Plant Maintenance (JIPM) standard of 85%. Reduced speed losses (11.73%) were identified as the primary inefficiency. Root causes included issues related to manpower, machinery, methods, materials, and the environment. To enhance effectiveness, the study recommends implementing predictive maintenance within a Total Productive Maintenance (TPM) framework. This approach focuses on proactive monitoring and timely interventions to minimize downtime and improve production efficiency. By adopting these measures, PT XYZ can achieve better machine utilization, reduce production losses, and ultimately increase productivity to meet industry standards.