I. PET Injection Molding: The "Invisible Expert" in Daily Life

You may not have heard of PET injection molding, but you must have used its products. Mineral water bottles, cosmetic packaging, medical devices... These daily necessities are all closely related to it. PET (polyethylene terephthalate) is a high - performance plastic. Thanks to its advantages such as high transparency, good strength, and recyclability, it has become a "star material" in the plastic processing industry.

Industry Data

In 2023, the global PET market size is expected to exceed $40 billion, with an annual growth rate of 5.2%.

China is a major producer and consumer of PET, accounting for more than 35% of the global market share.

II. The 4 Core Stages of PET Injection Molding

1. Material Selection: Food - Grade, Medical - Grade, or General - Grade - Are You Using the Right One?

Food - grade PET must pass the FDA certification to ensure it is safe and non - toxic.

Medical - grade PET has even higher requirements. It needs to have biocompatibility and high - temperature resistance.

2. Mold Design: A Good Mold Is Half the Battle

Mold design directly affects the appearance and performance of the product.

The conformal cooling technology can shorten the cooling time and improve production efficiency.

3. Process Parameters: The "Golden Triangle" of Temperature, Pressure, and Time

Temperature Control: The melting temperature of PET is usually between 260°C - 280°C.

Pressure Adjustment: Excessive holding pressure can cause internal stress, while insufficient holding pressure may lead to shrinkage.

4. Post - Processing: Making the Product Perfect

Dehumidifying and Drying: The moisture content of PET materials needs to be controlled below 0.02%.

Annealing Treatment: It can eliminate internal stress and improve product stability.

III. Common Problems and Solutions

Problem: Bubbles or Silver Streaks in the Product

Cause: The material is not fully dried or the temperature is too high.

Solution: Use a dehumidifying dryer and control the heating temperature.

Problem: Product Deformation or Shrinkage

Cause: Uneven cooling or insufficient holding time.

Solution: Optimize the mold cooling system and extend the holding time.

Problem: Uneven Surface

Cause: The mold surface is rough or the injection speed is too fast.

Solution: Polish the mold and reduce the injection speed.

IV. Industry Future: Intelligence and Greenization

Intelligent Upgrade

Intelligent injection molding machines can use sensors to monitor parameters such as temperature and pressure in real - time, and automatically adjust the process to reduce human errors.

Case: After a certain enterprise introduced an intelligent system, the yield rate increased by 15% and the production cost decreased by 10%.

Green and Environmental - friendly Trend

The recycled PET (rPET) technology is mature, which can reduce carbon emissions by 30%.

Policy Support: The EU requires that by 2030, the proportion of recycled materials in PET bottles should not be less than 30%.

Expansion of High - end Applications

Automotive Field: PET composites are used to manufacture lightweight components.

Electronics Industry: High - flame - retardant PET is used to manufacture mobile phone cases and chargers.

Conclusion

PET injection molding is not only an important part of the manufacturing industry but also a key force in promoting environmental protection and technological development. In the future, with the continuous progress of technology, PET injection molding will bring more innovations and breakthroughs.

References

"2023 Global PET Market Research Report"

Official Website of the China Plastics Processing Industry Association