How to avoid scratches when PET preforms are injected- Taizhou Shunke Moulding Co., Ltd

Why do PET preforms have scratches, and what should we pay attention to when injection molding?

PET material has many advantages, and it is usually used in packagings, such as medicine bottles, cosmetic bottles, and beverage bottles we see in our daily life, etc. are all made of it. The production process of pet preforms is relatively complicated. If there is an error in any link in the middle, various problems may occur, such as cracks, scratches, a and so on. Today, we will mainly analyze why there are scratches on the pet preform, and then understand what aspects need to be paid attention to during the injection molding process of the preform.

Reasons for scratches on PET bottles

1. After the pet preform injection mold is opened, it may be damaged due to a little bit of residual temperature, and then scratches appear.

2. The finished pet preforms may also be bumped during transportation, which is also one of the reasons for scratches.

3. The pet perform may be scratched during the blow molding process due to the kneading process.

4. When using pet-bottled products, if you are not careful, it may cause damage. Like the cola we often drink, there is a high probability of scratches when it is packaged.

Precautions for PET perform injection molding

1. Before the PET preform is injected, the material needs to be dried for three or four hours to prevent the moisture in the pet from exceeding the limit and affecting the quality of the product.

2. The template and the mold of the injection molding machine will need to be separated by a heat shield, and there should be sufficient exhaust during injection molding to prevent the pet preform from breaking.

3. The melt temperature is controlled at 270-295°C, and the air injection method can be used for measurement when the pet preform is injected.

4. The injection time of pet preforms should be fast, and the time can be controlled within four seconds.

5. The back pressure is lower than 100 bar to prevent wear and tear during the injection molding of pet preforms.

6. The residence time should not be too long. Generally, if the downtime does not exceed 15 minutes, it only needs to be treated by air injection, and if it exceeds, it can be cleaned with viscosity PE.