PT. XYZ is a manufacturing company that produces various types of metal-based products with a make to order system. One of them is the Back Top Plate 450/456 (BTP 450/456) part which is a component of refrigerators. In the period of February-November 2020, PT. XYZ produces 15,395 units of BTP 450/456. However, BTP 450/456 products have the highest percentage of defective products. The average percentage of defective products is 3.06%, while the tolerance for the number of defects determined by the company is 1%. This indicates a problem in the production process. The most types of defects in the production process of 450/456 are broken with a percentage of 41.88%. Based on Critical to Quality, the process stages that do not meet the requirements in the drawing process can cause various types of defects, such as wrinkles, breaks, miss-sizing, process failures, scratch and dents. The Fault Tree Analysis method is used to identify the root cause of the type of broken defect. The root of these problems includes the absence of a guide for setting dies, the machine being operated for a long time, operator negligence, and the incorrect position of the plastic. The proposed improvement given are determining the optimal engine pressure, designing dies setting guides for operators, evaluating and improving the maintenance process, analyzing new machine requirements, supervisors giving good directions to operators, periodic work evaluations to assess operator performance, designing visual displays as reminders for operators, and designing aids for positioning plastics on materials.