What is PEEK CNC Machining

Table of Contents

PEEK (Polyether Ether Ketone) CNC machining is a specialized manufacturing process used to shape this high-performance thermoplastic into precision parts. Renowned for its exceptional strength, thermal stability, and chemical resistance, PEEK is widely employed in industries like aerospace, medical implants, and electronics. Its unique properties also make it an ideal choice for applications such as electrical cable insulation. This guide explores the benefits, challenges, and applications of PEEK CNC machining.

What is PEEK (Polyether ether ketone)?

CNC machining Peek

PEEK, or polyether ether ketone, is a high-performance engineering thermoplastic known for its exceptional mechanical properties and chemical resistance.

PEEK 1000 is a standard grade that offers a balance of properties suitable for a wide range of applications. For enhanced performance, variations like PEEK-HPV, PEEK-GF30, and PEEK-CA30 are available. PEEK-HPV is modified with lubricants for improved wear resistance, while PEEK-GF30 is reinforced with glass fibers to enhance its strength and stiffness. PEEK-CA30, on the other hand, is reinforced with carbon fibers, offering superior mechanical performance and thermal conductivity. These specialized grades make PEEK a highly adaptable material for CNC machining, meeting diverse industrial needs.

PEEK is generally divided into two categories: industrial grade and medical grade. Industrial grade PEEK is used in different industries such as aerospace, automotive, chemicals, electronics and energy, while medical grade PEEK is used in the healthcare and dental fields.

Properties of PEEK Plastic Material

  1. High Temperature ResistancePEEK can withstand continuous temperatures up to 250°C (482°F), retaining its mechanical properties even under high heat.
  2. Chemical ResistanceIt resists a wide range of chemicals, including acids, bases, and solvents, making it ideal for chemical processing and medical applications.
  3. Superior Mechanical StrengthPEEK offers exceptional strength and stiffness, maintaining integrity under stress and enabling it to replace metals in lightweight engineering.
  4. BiocompatibilityPEEK is biocompatible, non-toxic, and sterilizable, making it a common choice for medical implants and devices.
  5. Low Friction and Wear ResistancePEEK has excellent tribological properties, with low friction and high wear resistance, ideal for precision parts like gears and bushings.

Here is a comparative table showing the properties of Generic PEEK, USP Class VI PEEK (TECAPEEK), and PEEK GF30:

Property

Generic PEEK

USP Class VI PEEK (TECAPEEK)

PEEK GF30

Tensile Strength, Yield (MPa)

100-120

115

110-130

Elongation at Break (%)

20-30

10-20

3-5

Hardness (Shore D)

85-90

87

88-93

Heat Deflection Temperature (°C)

150-160

152

310-320

Glass Transition Temperature (°C)

143

143

143

Explanation of Materials

Generic PEEK: A baseline version of PEEK, offering high thermal stability and mechanical strength. Suitable for a wide range of general applications.

USP Class VI PEEK (TECAPEEK): A medical-grade PEEK compliant with USP Class VI standards, specifically designed for biocompatible and sterile environments, such as medical implants and devices.

PEEK GF30: PEEK reinforced with 30% glass fibers, significantly increasing its strength and thermal resistance, but at the cost of reduced elongation and increased stiffness. Ideal for structural and industrial applications.

Pros of PEEK CNC Machining

PEEK CNC Machining
  1. Exceptional Strength and Durability

One of the most significant advantages of machining PEEK is its exceptional strength. Known for its robust mechanical properties, PEEK is able to withstand high levels of stress without deforming or failing. It has a high tensile strength that makes it suitable for high-stress environments, like aerospace and automotive industries. The durability of PEEK ensures that components last longer compared to traditional materials, even when exposed to harsh operating conditions.

  1. High Thermal Stability

Another benefit of PEEK CNC machining is its thermal stability. PEEK has a high melting point, which allows it to perform at elevated temperatures without compromising its mechanical integrity. It can withstand continuous exposure to temperatures up to 250°C, making it ideal for components in high-temperature applications, such as electronics, engine parts, and medical devices that require stability in extreme conditions. This high thermal resistance also prevents the material from losing its shape or structural strength, which is common with many other plastics.

  1. Chemical Resistance

PEEK’s chemical resistance is one of its standout features, making it an excellent choice for applications where parts come into contact with aggressive chemicals, acids, or solvents. This material is resistant to a wide variety of chemicals, including fuels, oils, and even some industrial solvents. This resistance is particularly valuable in industries such as the chemical, pharmaceutical, and medical sectors, where equipment and components often encounter aggressive substances that would degrade other materials.

  1. Low Friction and Wear Resistance

The low friction properties of PEEK are another major advantage in CNC machining. When used in moving parts like bearings, gears, and seals, PEEK exhibits reduced wear and tear, leading to longer operational lifespans and reduced maintenance costs. Its wear resistance is one of the highest among thermoplastics, ensuring that components stay functional for longer, even under constant use. These properties are particularly valuable in automotive, aerospace, and industrial machinery applications, where minimizing downtime is critical.

  1. Biocompatibility

For medical CNC machining applications, PEEK offers the added benefit of biocompatibility. This material is non-toxic and compatible with human tissues, which makes it an ideal choice for implants and medical devices. Whether it’s used in spinal implants, surgical instruments, or prosthetics, PEEK can be safely used inside the human body without causing adverse reactions. Additionally, PEEK is sterilizable, which is crucial for maintaining hygiene and preventing infection in medical procedures.

  1. Lightweight yet Strong

Despite its strength and durability, PEEK is a relatively lightweight material, which provides significant benefits in industries like aerospace and automotive engineering. When used in place of metals, PEEK reduces the overall weight of the components, leading to better fuel efficiency and easier handling without compromising on structural integrity.

Cons of PEEK CNC Machining

  1. High material costs

One of the main disadvantagesof machining PEEK is the high material cost. Compared to other thermoplastics or metals, the cost of PEEK is much higher, which can increase the overall cost of production, especially when produced on a large scale.

 

  1. Machining complexity

CNC machining of PEEK requires specialized equipment and tooling as it is a high performance material that is difficult to cut or shape. Due to its strength and stiffness, special cutting tools and slower machining speeds are required to avoid damaging the material or tools.

 

  1. Low temperature brittleness

Although PEEK is highly resistant to high temperatures, it becomes brittle at low temperatures. Therefore, it is not suitable for use in extremely cold or temperature fluctuating environments. Its brittleness at low temperatures limits its use in certain industrial applications such as cryogenic industries or products that need to withstand freezing temperatures.

 

  1. Limited availability of prefabricated components

Another disadvantage is the limited availability of pre-fabricated PEEK components. Many industries rely on off-the-shelf components, but because PEEK is often machined to specific tolerances, it can be difficult to find standardized pre-fabricated parts. This limits the speed of product development or assembly, as each component may require custom machining.

 

  1. Potential for material degradation during processing

Although PEEK is a tough material, it may experience some degree of material degradation during CNC machining due to high friction and heat buildup. If machining parameters are not properly controlled, excessive heat can cause the material to soften or degrade, compromising the integrity of the final product.

 

  1. Recycling Difficulties

While PEEK is a durable, high-performance material, it is not easily recycled. Once a PEEK part has been used in a product, it can be difficult to break it down and reuse it. This can create environmental waste in industries that rely on large quantities of PEEK.

Tips for PEEK Plastic Machining

Choose the right cutting tool

For PEEK CNC machining, use carbide tools with sharp edges and avoid dull tools to minimize heat generation and prevent material degradation.

 

Optimize cutting speeds and feed rates

Set cutting speeds and feed rates to moderate levels. Too fast speeds can cause excessive heat buildup, softening the material, while too slow speeds can result in a poor surface finish.

 

Apply adequate cooling

Because PEEK is heat sensitive, using coolant or air flow during machining can help control temperature and prevent softening or deformation.

 

Avoid overheating

PEEK has a high melting point, but it can soften or even degrade if subjected to excessive heat during machining.

 

Be careful with small features

When machining small, intricate features or thin-walled parts, reduce feed rates and depth of cut. This can prevent delicate structures from warping or breaking.

Applications of PEEK machined parts

PEEK machined parts

Here are some common applications for PEEK machined parts:

Aerospace

– High temperature parts: bushings, seals and bearings.

– Electrical insulators: Insulation parts in avionics systems and other avionics equipment.

 

Medical

– Surgical instruments: Surgical tools and medical devices.

– Implants: Spinal implants, dental implants and other implants for orthopedic applications.

– Sterilization resistant parts

 

Automotive

– High performance parts: Engine parts such as gaskets, seals and bearings.

– Electric vehicle parts: Insulation parts, connectors and battery parts.

 

Oil and gas

– Seals and valves: Ideal for parts such as seals, valve seats and bearings in downhole drilling equipment and subsea systems.

– Pump parts: Pump parts.

 

Chemical machining parts

– Chemical pumps and valves: Seals, valve seats and bushings in chemical processing equipment.

What is the difference between PEEK machining, PEEK 3D printing or PEEK injection molding?

The main differences between PEEK machining, PEEK 3D printing, and PEEK injection molding lie in the manufacturing methods and material properties.

 

PEEK machining involves cutting or shaping solid PEEK material using CNC machines. It offers high precision and is ideal for complex, custom parts but can be time-consuming and costly due to the material’s rigidity.

 

PEEK 3D printing (additive manufacturing) builds parts layer by layer from PEEK filament. It’s suitable for creating prototypes and complex geometries but may have lower mechanical properties and precision compared to machining.

 

PEEK injection molding involves injecting molten PEEK into a mold, forming parts quickly and in large volumes. This method is cost-effective for mass production but less flexible for complex designs or small batches compared to machining or 3D printing.

Conclusion

Do you need prototype PEEK parts or high volume production of PEEK parts, EASIAHOME can provide professional 3-axis and 5-axis CNC PEEK plastic machining services including milling and turning. With our experienced team of CNC experts, we can provide you with the highest quality CNC PEEK plastic machining solutions.

Frequently Asked Questions

Q: What is the best way to eliminate burrs on PEEK parts?

A: The best way to eliminate burrs on PEEK parts includes using sharp tools with proper CNC settings, manual deburring with files, cryogenic deburring, vibratory finishing, or laser deburring, depending on the part size and complexity.

 

Q:What are the surface treatment methods for CNC PEEK plastic processing?

A: Surface treatments for CNC PEEK parts include polishing, sandblasting for matte finishes, plasma treatment for improved adhesion, chemical etching for better bonding, and coating or texturing for enhanced functionality or appearance.

 

Q: What types of CNC machines are used for machining PEEK?

A: CNC milling machines, CNC lathes, and multi-axis machining centers are commonly used to machine PEEK due to their ability to handle tough materials.

 

Q: Is PEEK CNC machining cost-effective?

A: While CNC machining of PEEK can be more expensive than machining other materials, the high performance and longevity of PEEK often justify the cost for specialized applications.

 

Q: Why is PEEK commonly used in CNC machining?

A: PEEK is used in CNC machining due to its durability, resistance to wear, and ability to perform in harsh environments, such as aerospace, medical, and automotive industries.

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