Dimensional Instability: This occurs when the molded part exhibits inconsistent shrinkage due to poor mold manufacturing accuracy, unstable injection molding process conditions, or improper post-processing of the product. 7.1 Causes 7.2 Solutions 7.1.1 Unstable electrical or hydraulic system of the machine. 7.2.1 Check for faults in electrical components or hydraulic systems; regularly clean elect...

Weld Line: When two or more streams of molten resin meet and the temperature drops during flow, the resin at the junction fails to fully fuse or bond. This results in a fine line formed along the surface or inside the molded part at the point of convergence. 6.1 Causes 6.2 Solutions 6.1.1 Low nozzle temperature or low mold temperature. 6.2.1 Increase melt and mold temperatures to improve resin flo...

Delamination or Peeling: This defect occurs when foreign materials are mixed into the raw material, the mold temperature is too low, or the material compatibility is poor. Excessive shear stress during melt flow along the mold surface causes the material to separate into thin layers, resulting in peeling or delamination. 5.1 Causes 5.2 Solutions 5.1.1 Material not properly dried. 5.2.1 Dry the mat...

Flash and Burrs: When the molten material enters the gaps between the mold parting surfaces or the joints between the mold and the slider, excess thin fins or burrs appear on the molded part. 4.1 Causes 4.2 Solutions 4.1.1 Poor closing or misalignment at the parting surface. 4.2.1 Increase clamping force; repair the mold parting surface to ensure tight fitting. 4.1.2 Excessive clearance between th...

Silver Streaks: Shiny, silvery lines appearing on the surface of the molded product or near the gate along the flow direction. These are caused by excessive moisture or volatile substances in the material, poor adhesion between the melt and the mold, or rapid cooling after the melt has been subjected to excessive shear stress—resulting in needle-like or mica-like streaks. In addition, if the silve...

Sink Marks (Depressions) Surface dents or depressions appear on molded parts. This defect occurs when the molten resin shrinks in volume during cooling and solidification but is not sufficiently compensated by additional material. It often appears on the backside of thick sections or behind ribs. Causes (2.1) Solutions (2.2) 2.1.1 Runner or gate too small, or insufficient number of gates. 2.2.1 Im...

Short shot / Incomplete filling The molten resin cannot completely fill the mold cavity. Causes (1.1) Solutions (1.2) 1.1.1 Injection volume insufficient; not enough material added. 1.2.1 Increase the material feed. 1.1.2 Inadequate plasticizing capacity or insufficient residual material. 1.2.2 Replace the machine or adjust process parameters to increase residual material. 1.1.3 Plastic particle s...