Analysis of brittle causes of injection mold products

Part of the injection mold molding products brittleness is caused by internal stress, generally speaking, the brittle molding products are usually injection mold, equipment, process and injection product design of a link out of the problem. For example, choose a well-designed screw, so that the temperature distribution is more uniform when plasticizing; If the temperature of the material is uneven, it is easy to accumulate too much heat in the local area, leading to the degradation of the material. The following is a detailed analysis of each link.

One. Injection molding equipment

1. There are obstacles in the cylinder of injection machine, which can easily cause melt degradation.

2. The plasticizing capacity of the injection molding machine is too small, and the plasticizing capacity of the cylinder is insufficient; The plasticizing capacity of the machine is too large, the heating and shearing time of the plastic in the barrel is too long, and the plastic is easy to aging, which makes the product brittle.

3. The ejecting device of the injection molding machine is unbalanced, and the cross sectional area of the ejecting rod is small.

Two. Injection mold

1. The gate of injection mold is very small, so it is necessary to consider adjusting the gate size or adding auxiliary gate.

2. If the diverter is too small, try to balance it reasonably or increase the diverter size.

3. Poor injection mold structure leads to abnormal injection cycle.

Three. Injection molding process

1. The temperature of barrel and nozzle is too low. If you want to improve, you need to increase the injection temperature.

2. Reduce the screw premolding back pressure and speed, reduce the plastic degradation caused by shear overheating.

3. The plastic mold should have appropriate release slope. When it is difficult to release the mold, the cavity temperature should be increased to shorten the cooling time.

Iv. Design of injection molding products

1. The product has sharp corners with stress cracking, clearance or thickness difference.

2. Product design is too thin or hollow out too much.

Injection mold design must increase the size of the main channel, diverter and gate, too small main channel, diverter or gate is easy to lead to excessive shear heat, resulting in polymer decomposition. The mission of Fansstar is to master the core technology of injection molding production, to communicate and analyze the technology before the production of injection molding with customers from the production needs of finished products, so that the injection mold delivery time is short, the service life is long, the mass production is fast and the finished product quality is excellent! Have the need of injection molding injection mold welcome to contact us!