PEEK Injection Molding - Drying and Preheating

In the PEEK material injection molding process, pre-treatment before injection molding is a crucial step that plays a decisive role in the quality and performance of the final product.

The necessity of peek preprocessing

Although PEEK material has excellent performance, due to its high melting temperature and viscosity, its flowability is poor under conventional injection molding conditions, making it difficult to uniformly and fully fill complex mold cavities. Especially for injection molded products with fine structures, thin-walled features, or small pore sizes, ordinary injection molding processes are prone to problems such as insufficient filling and molding defects. Preprocessing aims to improve these conditions and enhance the processing performance of materials.

If the product structure is very fine and the thickness is very thin, our high flow PEEK can be used. Under standard testing methods, the melt index can reach 110g/min, improving the integrity of the product.

Dehumidification dryer

Drying pretreatment

Reason for drying:

PEEK material hasPEEK material has hygroscopicity and will absorb moisture from the air during storage and transportation. When materials containing moisture enter the high-temperature injection molding environment, the moisture evaporates instantly, forming bubbles and voids inside the product, leaving defects such as silver threads and stripes on the surface of the product, seriously affecting the appearance and mechanical properties of the product.

Drying process: 

Generally, PEEK materials are placed in a hot air circulation drying oven at 150-180 ℃ for 3-4 hours until the moisture content of the material decreases to below 0.02%. During the drying process, it is necessary to regularly flip the material to ensure that every part can be fully dried. In addition, vacuum drying can also be used to achieve efficient drying at lower temperatures, which is particularly suitable for special PEEK materials that are sensitive to temperature.

The significance of product quality: After sufficient drying, PEEK material can be stably plasticized and flowed during the injection molding process, avoiding various quality problems caused by water vaporization. This not only improves the appearance quality of the product, but also enhances its mechanical properties such as strength and toughness, ensuring the reliability of the product in various harsh application scenarios.

PEEK Preheating  

Temperature setting basis: 

Preheat PEEK material to 160-180 ℃, this temperature range has been verified through extensive experiments and practices. Within this temperature range, it can effectively reduce the melt viscosity of the material, enhance the activity of molecular segments, and improve its fluidity, without causing thermal degradation or other irreversible chemical changes of the material due to high temperature. Once the temperature exceeds the appropriate range, it may cause material performance degradation, such as decreased mechanical properties, color changes, etc.

Preheating Operation method:

Usually, a hot air circulating oven is used for preheating treatment. Place the PEEK material evenly on the oven tray to ensure even heating of the material. During the preheating process, it is necessary to monitor the temperature inside the oven in real time to ensure that the temperature remains stable within the set range. At the same time, according to the thickness and quality of the material accumulation, the preheating time should be adjusted reasonably, usually 2-3 hours, to ensure that the material as a whole achieves the expected preheating effect.

The impact on the injection molding process: 

PEEK materials that have been preheated and pre treated can achieve uniform plasticization faster after entering the injection molding machine barrel, shorten the plasticization cycle, and improve production efficiency. In the injection molding stage, better fluidity enables the material to quickly and completely fill every corner of the mold cavity, especially for thin-walled and complex structured products, effectively avoiding defects such as cold lines and missing materials caused by untimely filling, significantly improving the molding quality and dimensional accuracy of the product.

In summary, the pre-treatment of PEEK material before injection molding has laid a solid foundation for the subsequent injection molding process through scientific preheating and drying processes, and is irreplaceable in improving the quality of injection molded products and meeting diverse industrial production needs. In actual production, each stage of pre-treatment should be strictly controlled, and pre-treatment parameters should be flexibly adjusted according to material characteristics and product requirements to achieve the best injection molding effect.