With 25 years of experience in the plastic mold industry, Green Vitality Industry Co.,LTD is a high-quality INJECTION MOLD factory. What are the reasons and solutions for brittle products when we encounter them in injection molding? After injection molding, the impact performance of plastic parts compared with raw materials has been greatly reduced, which is commonly known as brittleness. The direct cause of brittleness is that the internal stress of plastic parts is too large.

1. Material

Injection before setting the appropriate drying conditions, the material if continuous dry for a few days or the drying temperature is too high, although can remove classification of volatile substances, but would also lead to material, especially the heat-sensitive plastic, the second will reduce the use of recycled materials, increase the proportion of the original raw, choose suitable material, with high strength plastic.

2. Mold design

Increase the size of the main channel, shunt and gate. The runner should avoid sharp angles. Too small runner, shunt or gate size and sharp edges can lead to polymer decomposition.

3. Injection molding machine

Should choose the right screw, plasticizing temperature distribution is more uniform, if the material temperature is not uniform, it is easy to accumulate too much heat in the local, leading to the degradation of the material.

4. Process conditions

The first step is to reduce the temperature of the cylinder and nozzle, reduce back pressure, injection pressure, screw speed and injection speed, reduce excessive shear heat generation, avoid polymer decomposition, reduce mold opening speed, ejection speed and ejection pressure.

5. Plastic parts design

When designing the middle part of the plastic fluid to flow through the part do not appear too thin wall thickness, products with prone to stress cracking sharp corners, inserts, gaps or thickness of the design is very different.

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