PET Material Drying and Handling for Injection Molding

In PET injection molding production, proper drying and handling of PET raw materials significantly influence product quality and manufacturing efficiency. Due to PET’s hygroscopic nature, appropriate pre-processing and storage practices are essential for stable molding and high-quality output.Below are key PET material handling practices widely adopted in industrial injection molding.

1. PET Material Drying

PET readily absorbs moisture, which can cause hydrolysis during melting, leading to brittleness and optical defects.

Use a desiccant dryer for thorough drying;

Typical drying temperature is around 160°C;

Drying time is recommended for 4–6 hours or longer;

Target moisture content should be below 50 ppm.

Effective drying helps reduce moist-induced defects and improves molding consistency.

2.PET Material Storage

Dry PET can regain moisture during storage if not properly managed.

Store in airtight containers or silos equipped with dehumidifiers;

Monitor moisture levels regularly;

Avoid exposure to humid environments.

Good storage practices help maintain material integrity and reduce processing risks.

3.Process Setup in Injection Molding

In addition to proper drying and storage, correct molding parameters further enhance product quality:

Set appropriate back pressure to ensure uniform melting;

Control injection speed for complete cavity filling;

Adjust holding pressure and time to reduce sink marks and warpage.

These practices help improve production stability and reduce defect rates.

Conclusion

PET raw material handling is a fundamental step in achieving stable, efficient, and high-quality injection molding production. By implementing proper drying, storage, and process parameter control, manufacturers can enhance consistency and reliability in PET molding operations.