Product quality measurement is an important aspect of the production process. This study aims to determine the types of defects that often occur and find a recommendation for improvement to CNC machine product of Takamaz GSL 15 at Technical Implementing Unit Metal Yogyakarta. In this study, a Pareto diagram is used for analysis the types of defects. Analysis of priority value regarding severity (S), occurrence (O), and detection (D) characteristics is performed by using Failure Mode and Effect Analysis (FMEA) method. Meanwhile, Fishbone is used to analyze more deeply about the potential caused by the type of defect. This study succeeded in finding four types of records on the product; they are cracked pinhole, imperfect castings, hole defects on the surface, and minus drain lines. This study recommend to include periodic and ongoing supervision of the metal casting process, make metal wheel chain in one production line, use modern equipment or machines, replace the drill bits periodically during machining process and replace sandpaper with a softness level according to SOP.