PEEK material Properties

PEEK plastic exhibits superb mechanical properties and is highly resistant to chemicals and thermal degradation, making it a highly desirable material for plastic injection molded products. PEEK resin holds up well against high temperatures and long-term liquid submersion and is very durable in harsh environments. PEEK plastic makes an excellent reinforcement material, providing great tensile strength with low weight.

Features and benefits of PEEK material properties include:

• High chemical resistance, even at elevated temperatures
• High hardness, stiffness & strength
• Excellent fatigue & stress-crack resistance
• Excellent resistance to high pressure water & steam without significant degradation
• Can be sterilized via autoclave
• Easy to machine & fabricate
• UL 94 V-0 flammability rating
• Very low smoke/toxic gas emission when exposed to flame
• Suitable for continuous use in application temperatures up to 338°F/170°C
• Unfilled PEEK is FDA-approved for food contact

Key elements for successful PEEK injection molding include:

1. Material Selection: Choose the appropriate PEEK material grade based on the specific application requirements, considering factors such as mechanical properties, temperature resistance, chemical resistance, wear resistance, and regulatory compliance.

2. Mold Design: Design the mold with precision to accommodate the desired part geometry, gating, venting, and cooling requirements for PEEK injection molding. Consider features such as draft angles, parting lines, and vent channels to facilitate mold release and minimize defects.

3. Tool Fabrication: Fabricate the mold tooling using high-quality materials and precision machining techniques to achieve tight tolerances, smooth surface finishes, and durability. Verify the accuracy of the mold components through thorough inspection and validation.

4. Injection Molding Machine: Utilize a well-maintained injection molding machine with appropriate specifications for processing PEEK material, including barrel temperature control, injection pressure capability, injection speed control, and shot size capacity.

5. Injection Process Optimization: Optimize process parameters such as barrel temperature, injection pressure, injection speed, cooling time, and hold pressure to achieve consistent part quality, minimize cycle times, and prevent defects such as warpage, sink marks, or surface blemishes.

6. Injection Unit: Ensure that the injection unit is properly calibrated and equipped with precision metering and mixing systems to accurately dispense the PEEK material into the mold cavity. Pay attention to screw design, back pressure control, and screw/barrel alignment to prevent material degradation and ensure uniform melt quality.

7. Mold Temperature Control: Maintain precise control over mold temperature using water or oil circulation systems to achieve uniform cooling and solidification of the PEEK material, preventing defects such as warpage, shrinkage, or surface irregularities.

8. Venting and Degassing: Ensure proper venting and degassing of the mold cavity to eliminate trapped air and gas bubbles during the injection process, preventing defects such as voids, bubbles, or surface imperfections in the molded parts.

9. Part Ejection and Handling: Implement reliable part ejection mechanisms (e.g., ejector pins, air ejection) and handling systems to safely remove the molded parts from the mold cavity without damage or deformation.

10. Quality Control and Inspection: Establish comprehensive quality control measures and inspection procedures to monitor part dimensions, surface finish, and physical properties. Conduct regular inspections and testing to verify part quality and consistency.

11. Training and Expertise: Ensure that operators and technicians receive proper training and have expertise in PEEK injection molding techniques, equipment operation, mold maintenance, and troubleshooting to address any challenges that may arise during production.

By addressing these key elements and optimizing the PEEK injection molding process, manufacturers can produce high-quality, precision-molded parts with consistent performance and reliability for a wide range of applications.   

Polyetheretherketone (PEEK) is a high-performance engineering thermoplastic known for its excellent mechanical properties, chemical resistance, and thermal stability. When it comes to injection molding PEEK, certain key elements and considerations are essential to ensure successful processing and high-quality parts.

Key Elements for PEEK Injection Molding

1. Material Handling and Preparation

• Drying: PEEK is hygroscopic and must be thoroughly dried before processing to avoid defects like hydrolysis and degradation. Recommended drying conditions are 150°C (302°F) for at least 3-4 hours.
• Storage: Keep PEEK in a dry environment and sealed containers to prevent moisture absorption.

2. Molding Equipment

• High-Temperature Capabilities: Injection molding machines must be capable of handling the high processing temperatures required for PEEK, typically ranging from 360°C to 400°C (680°F to 752°F).
• Corrosion and Wear Resistance: Use bimetallic barrels and hardened screws to withstand PEEK's abrasive nature and high processing temperatures.

3. Mold Design

• Temperature Control: Mold temperatures should be controlled and maintained between 160°C and 200°C (320°F to 392°F) to ensure proper flow and crystallinity.
• Gate Design: Use appropriately sized gates (typically edge gates or submarine gates) to allow for smooth flow and minimize stress concentration.
• Venting: Ensure adequate venting to prevent gas entrapment and voids in the molded parts.

4. Processing Parameters

• Injection Speed: Moderate to high injection speeds help to fill the mold cavities quickly and prevent premature solidification.
• Injection Pressure: High injection pressures (up to 2000 bar) are often required due to PEEK's high viscosity.
• Cooling Time: Optimize cooling times to allow parts to solidify adequately without causing warpage or shrinkage.

5. Post-Processing

• Annealing: Some PEEK parts may require annealing to relieve internal stresses and improve dimensional stability. Annealing is typically done at 200°C to 250°C (392°F to 482°F) for several hours.

Common Applications of PEEK Injection Molding

• Medical Devices: Surgical instruments, implants, and diagnostic equipment components.
• Aerospace: Components requiring high strength-to-weight ratios and resistance to high temperatures.
• Automotive: Engine components, transmission parts, and other under-the-hood applications.
• Electronics: Connectors, insulators, and high-performance electrical components.

Injection molding PEEK requires meticulous attention to material handling, equipment capabilities, mold design, and processing parameters. By adhering to these key elements, manufacturers can produce high-quality, reliable PEEK parts suitable for demanding applications across various industries. For more detailed guidance and best practices, consulting with PEEK material suppliers and injection molding experts is recommended.

Ming-Li Capabilities in PEEK Material Molding

Ming-Li Precision offers advanced capabilities in molding PEEK (Polyether Ether Ketone), a high-performance engineering thermoplastic known for its exceptional mechanical properties, chemical resistance, and thermal stability. With over 100 tons of PEEK material molding production experience, Ming-Li is a valuable partner for industries requiring precision and durability in challenging environments.