Causes and solutions of cracking caused by residual stress in injection molding

Cracking caused by residual stress in injection molding is a common problem, which may lead to a decline in product quality and affect the service life and appearance of the product. This paper will discuss the causes and effects of cracking caused by residual stress in injection molding from the aspects of material composition and injection mold design, and introduce some effective preventive measures and solutions.

Material composition is one of the important factors affecting residual stress in injection molding. If the strength and toughness indexes in the material do not meet the requirements, residual stress will be generated during the molding process, resulting in the generation of cracking. In addition, the thermal stability of the material also affects the magnitude and distribution of residual stress. If the thermal stability of the material is poor, it will produce excessive thermal stress in the molding process, which leads to the generation of cracking.

Injection mold design is also one of the important factors affecting the residual stress of injection molding. The design and structure of injection mold will directly affect the flow and cooling of materials in the molding process, thus affecting the magnitude and distribution of residual stress. If the design and structure of the injection mold is not reasonable, it will produce excessive thermal stress and strain in the molding process, which leads to the generation of cracking.

1. In view of cracking caused by residual stress of injection molding, we can take the following preventive measures and solutions:

2. Improve material selection. Select the materials that meet the requirements, and adjust the performance index of the materials according to the requirements of the product and the actual situation.

3. Optimize injection mold structure. Reasonable design of injection mold runner, gate, vent hole and other parts, avoid excessive thermal stress and strain, reduce cracking.

4. Use hot runner technology. Hot runner technology can reduce the heat loss of injection mold, improve molding efficiency and reduce cracking.

5. Use cooling techniques. Reasonable design of injection mold cooling system, using effective cooling methods, reduce the thermal stress and strain of materials, reduce cracking.

Cracking caused by residual stress of injection molding is a common problem, we need to start from the material composition, injection mold design and other aspects, take effective preventive measures and solutions, reduce product defects and damage, improve product quality and service life. At the same time, we also need to strengthen the monitoring and control of injection molding residual stress in daily production, timely discovery and solution of problems, to ensure product quality and stability.