Causes and Solutions of Gas Formation in Injection Molding Machine Barrels

Causes of Gas Formation in Injection Molding Machine Barrels

Gas formation in injection molding machine barrels may be generated due to several reasons:

• Uneven cooling: When the section of the barrel exposed to cooling water has a relatively low temperature, the circulation of molten plastic slows down, making it easier for rising gases to become trapped in that area.
• Material reactions inside the cylinder: If the material remains in the barrel for too long, various reactions can occur, such as moisture evaporation and gas separation.
• Excessive injection speed: When the injection speed is too fast, the temperature of the molten plastic may not stabilize properly, causing gas to be trapped within the melt.

Impact of Gas Formation in Injection Molding Machine Barrels

• The presence of gas in the barrel affects both the efficiency of the injection molding machine and the quality of the products:
• Reduces machine stability and production efficiency, leading to higher defect and scrap rates.
• Affects product appearance, resulting in problems such as oil stains, bubbles, voids, sink marks, or honeycomb structures.

Solutions to Gas Formation in Injection Molding Barrels

• Cleaning treatment: If gas issues are caused by material reactions inside the barrel, regular cleaning of the injection molding machine can help reduce the problem.
• Adjust injection parameters: Issues caused by excessive speed or uneven cooling can be mitigated by adjusting processing parameters. For example, reducing injection speed or increasing melt temperature can improve gas release.
• Use appropriate raw materials: Choosing suitable raw materials is another effective way to prevent gas formation. Since different plastics have different processing parameters and properties, materials should be selected according to the application.
• Optimize equipment settings: Proper adjustments to equipment settings—such as temperature, pressure, and venting—can improve melt uniformity and prevent gas from being trapped.

The causes of gas formation inside injection molding machine barrels are complex and varied, and the corresponding solutions should be chosen based on the specific situation. By minimizing air intake, optimizing molding parameters, improving mold venting, and using degassing devices when necessary, manufacturers can effectively reduce or eliminate gas-related problems. This leads to improved product quality, reduced costs, and more stable production efficiency.