Burn marks are a phenomenon in which a portion of a molded product burns and turns black and carbonized. This occurs when the molten resin is injected at high pressure, causing the air in the cavity to lose its place and become compressed, generating high heat. Burn marks tend to occur not in the early stages of molding, but when mass production gets underway, and the molding process is often troubled by the need to prevent burn marks. In addition to reducing the injection speed, it is effective to provide air vents to release gas and to control resin flow by changing the gate position and wall thickness., The output of an injection molding machine is determined by a combination of factors, including mold design (cavities), material properties (gram weight), and machine settings (holding pressure, cooling time, and cycle speed)., We will explain the output results of injection molding analysis and how the obtained information can be used in product/mold design and molding process. 1. Introduction. 2. What can an injection molding analysis tell us? 3. How will the analysis results be used? 4. Some of the common molding defects. 5. Summary..