Common defects in injection molding and their detailed characteristics

1. Introduction

Injection plastic molding is widely used in many industries, but a variety of defects can occur during the manufacturing process. These defects often appear in the form or surface and can have a significant impact on quality. This article details the general types and characteristics of these defects, which are divided into shape and surface defects

1. List of defects in molded products
   

1. Geometrical imperfections
   
   1. Short Shot
      

      This defect refers to a molded product that is incomplete and partially missing. It is usually noticeable in the corners of molds and in parts of complex shapes.

      
      

1. Flashing and Burrs
   

   This phenomenon is excess material on the edges of a molded product. This is usually caused by resin leaking from gaps in the mold.
   

   
   

   
   

1. Sink Marks
   

   This is a phenomenon in which a molded product shrinks after cooling. This defect is especially likely to occur in thicker parts of the molded p
   

   
   

   
   

1. Warping
   

   This is a condition in which the molded product warps. In many cases, this defect is caused by uneven cooling of the molded product.
   

   
   

   
   

1. Weld Lines
   

   This is a defect where a weak line forms at the confluence of the material flows. This line is usually where the physical strength is lower.
   

   
   

   
   

   
   

1. Voids
   

   Cavities occur inside the molded product. This is often caused by uneven cooling of the plastics.
   

   
   

1. Air Traps
   

   This is a condition in which air bubbles are trapped inside the molded product. This usually occurs when material is injected into the mold at high speed.
   

   
   

1. Cracks and Crazing
   

   This is a defect that causes cracks in molded products. This is often caused by resin degradation or external forces.
   

   
   

   
   

1. Gate Vestiges
   

   Residual material from the gate area is observed. This is affected by mold design and injection conditions.
   

   
   

   
   

1. Surface defects in injection plastic molding
   
   1. Color Streaks
      

      The color of the molded product may not be uniform, which usually occurs when the mixing of materials is incomplete
      

      
      

1. Jetting
   

   Flow traces are left on the molded product. This defect occurs during the process of resin injection into the mold at high speed.
   

   
   

   
   

2.  Silver Streaks
   

   Striate patterns appear on molded products. This is often caused by moisture or impurities in the material.

   
   

   
   

1. Flow marks & Flow Lines
   

   A linear pattern appears on the molded product. This usually occurs when the material flow is uneven.

   
   

   
   

1. Splay
   

   A droplet-like or silvery pattern appears on the surface. This usually occurs when moisture in the material evaporates.
   

   
   

1. Burning
   

   This is a condition in which molded products are scorched by high temperatures. This is caused by excessive heating of the resin.

   
   

   
   

1. Delamination
   

   Layers of the molded product may peel off. This is often caused by uneven cooling of the material.

   
   

1. Black Specks
   

   Black spots or specks appear on the molded product. This is usually caused by impurities in the mold or resin.

   
   

1. Degradation or Scorching
   

   This is a phenomenon in which molded products burn or change color. This occurs when the resin is heated excessively or deteriorates over time.