This research was conducted in the Vacuum Department of PT XYZ, which operates a CNC vacuum thermoforming machine for bus interior production. This machine is vital as it is the only production machine used continuously, making it prone to breakdowns that can hinder productivity. The research aims to implement Total Productive Maintenance (TPM) to enhance productivity by measuring Overall Equipment Effectiveness (OEE) and analyzing the Six Big Losses to identify the most significant factors contributing to unproductivity. The results show that productivity in the Vacuum Department is still below the ideal OEE value, with an average of 72.84%. The largest factor contributing to unproductivity is Reduce Speed Loss, with a time loss of 14.74 hours or 43.82%. To improve productivity, it is necessary to implement TPM approaches, including preventive and predictive maintenance, as well as operator training to enhance skills and minimize productivity decline.