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What should I do if the color of TPE material is uneven and the surface is dull during injection molding?

Release time:

2024/03/18

Source:

Website

TPE materials are widely used in injection molding, and it is also because there are more people who use TPE materials for injection molding, and the corresponding problems have increased.

First of all, we need to know where the cause of the problem is, whether there is a problem with the material, or other factors that cause the problem.

1. The temperature of the nozzle is too low, resulting in a decrease in the gloss of the surface of the product

The nozzle temperature should be increased, and the melt temperature should be increased.

2. The injection speed is too fast, and the material retention time is too long, resulting in the gloss of the product

The injection rate should be reduced to reduce the residence time.

3. The thermal stability of the material is poor and decomposes by heat

Materials with good thermal stability and gloss should be selected or heat stabilizers should be added to the materials.

4. The surface finish of the mold is poor, and the surface of the product is glossless

Carbon tool steel should be selected, and the mold surface should be carefully polished to improve the surface finish of the mold.

5、The temperature of the mold is too low, but the cooling rate is too fast, when the melt is still filling the mold, a hard shell is formed on the cavity wall, and the shell is subjected to various forces, which makes it white and muddy, thereby reducing the gloss of the surface of the product.

Measures such as increasing the surface temperature of the mold, reducing the cooling rate, or using local heating at the mold gate should be used.

6、Excessive release dosage can also lead to the above-mentioned defects on the surface of the product

A small amount of release agent should be avoided or used as much as possible, and the application should be even.

7、Impurities in the material, or the material is not dry, also has an impact on the surface gloss of the product

To remove impurities, dry the material.

8、The size of the runner and gate is too small, and the exhaust air is not passed, which will also affect the gloss of the surface of the product

The size of the runner and gate should be increased, and the exhaust groove should be increased

9、Too little back pressure during plasticization will lead to uneven plasticization of the material, and poor mixing of the material and colorant will also lead to uneven surface color.

Back pressure should be increased appropriately

The above is to share with you today about the problem of uneven color or insufficient surface gloss of TPE materials during injection molding, generally when this problem occurs, if you can't solve it yourself, it is recommended to contact the TPE material manufacturers you purchased in time, so that they can provide you with effective solutions.

If you have any other knowledge about thermoplastic elastomers that you want to know or consult, please call the hotline of Dongguan Guofeng Plastic Industry official website, we look forward to your call!

Key words：

Precautions for thermoplastic elastomers when injection molding!