The Challenges of PEEK Plastic Injection Molding

When it comes to plastic injection molding, polyetheretherketone (PEEK) is the material of choice thanks to its exceptional characteristics and properties, including very high rigidity, stability at very high temperatures, resistance to aggressive chemicals, and biocompatibility. However, to exploit the full potential of PEEK, a unique set of challenges must be overcome.

As a provider of precision plastic injection molding services, PreciKam has extensive experience with this high-performance polymer. In this article, we’ll explore the main challenges associated with PEEK injection molding and outline the elements to consider when molding to ensure optimal results for your projects. As a manufacturer, being better informed about PEEK plastic injection molding can eventually influence your choice of materials for your product or part.

4 Challenges of PEEK Plastic Injection Molding

All the benefits of polyetheretherketone plastic injection molding come with challenges that must be addressed for a successful outcome. Here’s what you need to know.

1. High Processing Temperatures

PEEK requires very high processing temperatures, typically between 340°C and 400°C (644°F – 752°F). These temperatures are essential to melt and inject the material into molds but can pose challenges, such as increased energy costs and potential mold damage.

Precise temperature control is critical to mitigate these issues, and pre-heating the material and molds can help prevent thermal shocks.

2. Mold Design Complexity

Designing molds for PEEK requires expertise due to the material’s high viscosity and shrinkage rates. Molds must be capable of handling high pressures and temperatures, and cooling channels must be carefully planned to avoid warping or deformation. Venting is also essential to allow trapped air to escape.

Precikam offers durable, top-quality molds specifically designed for high-performance materials like PEEK. Whether for medical device plastic injection molding, aerospace plastic injection molding or any other type of plastic injection molding, our expert mold design engineers can develop a customized solution, addressing these challenges while ensuring precision.

3. Cost Considerations

One of the significant costs in PEEK plastic injection molding is the need for top-notch injection molding machines that can deliver precision at extreme temperatures and pressures. On the other hand, mold production is also expensive, ranging from $1,000 to $100,000 depending on complexity.

Many manufacturers opt to do business with precision plastic injection molding specialists like PreciKam to reduce their costs for equipment, mold making, labor, and in-house training. This decision provides access to state-of-the-art equipment and expert advice at all times.

4. Potential for Degradation during Processing

PEEK is prone to degradation if exposed to prolonged high temperatures. Proper drying of PEEK pellets and careful control of processing temperatures are essential to avoid defects like voids and surface blemishes. Post-molding processes, such as annealing, can also help relieve internal stresses and improve the durability of finished parts.

Doing business with a company specializing in PEEK plastic injection molding enables you to meet these challenges, which might otherwise be insurmountable by any inexperienced manufacturer. This way, you’re assured of exceptional results that meet your requirements.

PEEK Injection Molding Process and Considerations

Due to its unique properties, PEEK requires a high degree of precision during injection molding. Therefore, it is important to plan each step carefully to achieve the best results. In addition to considering the cleanliness of the production environment, particularly in sectors such as medical and electronics, it’s also important to control temperatures, pressure, and mold design to ensure that the material performs as expected.

If any of these factors aren’t optimized, the resulting parts could suffer from defects, affecting their performance and durability.

Temperature Requirements

Due to its high melting point, processing PEEK requires strict temperature control. For unfilled PEEK, the barrel temperature should range between 360°C and 400°C. The mold temperature must be at least 170°C to support proper crystallization and flow. Higher temperatures up to 230°C may be used for reinforced grades to improve flow and dimensional stability.

Maintaining proper heating profiles is also essential for optimal material flow and preventing issues like incomplete mold filling or excessive shrinkage.

Pressure Considerations

Given PEEK’s high viscosity, injecting it into the mold requires significant pressure. Standard pressures for PEEK injection molding are between 100 and 200 MPa (14,500 to 29,000 psi). This high pressure helps the material fill every mold detail, but caution must be exercised. If the pressure is too low, the material may not fill the mold, leading to incomplete parts. If the pressure is too high, defects such as flashing ay occur. Balancing the right pressure is important for smooth mold filling and part quality.

Mold Design Considerations

PEEK requires specialized mold designs due to its high processing temperatures and shrinkage rates. Materials used for molds should have hardness between 52-56HRc, with BH13 steel commonly used for high-temperature strength and durability. Venting is critical, with 8-15 µm depth slots to prevent defects.

Heating methods like electrical or oil-based systems are recommended to maintain a uniform tool surface temperature of at least 170°C. Efficient cooling channels should be incorporated to ensure proper crystallization and dimensional stability for PEEK parts.

Cooling and Injection

Cooling is essential to ensure the dimensional stability of PEEK parts. Injection-molded parts made from PEEK plastic take longer to cool than other thermoplastics. Therefore, it is important to have cooling channels in the mold to control the cooling rate.

If the material cools too quickly, there is a risk of internal stress or warping issues. We also need to ensure that the injection process is fast enough to fill the mold without causing the material to cool too soon.

By addressing these factors carefully, we’ll ensure that the PEEK plastic injection molding process runs smoothly and that you get durable, high-quality parts every time.

In Conclusion

Although PEEK injection molding presents a number of challenges, the exceptional properties of the resulting parts make it an attractive process for many applications. At PreciKam, we have the expertise, equipment, and experience to meet these challenges effectively.

Because we understand all the challenges and constraints associated with PEEK plastic injection molding, such as high processing temperatures and complex mold design, we can help you harness the full potential of PEEK for your projects. Our meticulous attention to the injection molding process and related considerations enables us to consistently deliver superior-quality parts.

Whether you work in aerospace, medical, automotive, or any other industry requiring high-performance parts, our team is ready to partner with you to overcome these challenges and deliver superior PEEK injection-molded components.

Contact us to discuss how we can bring your PEEK injection molding projects to life, combining our technical expertise with your innovative designs to create parts that exceed expectations.