Solution to air bubbles generated by precision insert injection molding

Metal insert injection molding is a process that combines metal parts and plastics, and is widely used in various fields. In the process of injection molding, some product quality problems often occur, such as bubbles, whitening, flow lines, weld marks, insufficient filling, and edge overflow. The previous article has briefly introduced the solutions to overflow and insufficient filling. This article will continue to introduce the injection molding of precision inserts to produce bubbles. How to deal with it? According to the causes of bubbles, the countermeasures are as follows: 1. When the product wall thickness is large, the outer surface of the product cools faster than the middle part, so as the cooling progresses, the resin edge of the middle part shrinks The side expands to the surface, causing insufficient filling in the middle (center) part. This situation is called a vacuum bubble. The main solutions are: (1) Determine a reasonable gate and runner size according to the wall thickness. Generally, the gate height should be 50% to 60% of the product wall thickness. (2) A certain amount of supplementary injection material is left until the gate is sealed. (3) The injection time should be slightly longer than the gate sealing time. (4) Reduce the injection speed and increase the injection pressure. (5) Use materials with high melt viscosity grades. 2. Bubbles caused by the generation of volatile gases, the main solutions are: (1) Fully pre-drying. (2) Lower the temperature of the resin to avoid the generation of decomposition gas. 3. Air bubbles caused by poor fluidity can be solved by increasing the temperature of the resin and the mold, and increasing the injection speed. [Related recommendation] Learn more: 精の corporate culture Learn more: Continuous improvement and innovation are the key factors for the survival of stamping companies Learn more: Why most stamping factories are unwilling to quote foreign trade companies