In today’s demanding engineering environment, OEMs are constantly challenged to improve reliability, reduce component weight, increase operating life, and maintain performance in increasingly aggressive operating conditions. Traditional materials such as metals and standard engineering plastics often struggle to meet these requirements, particularly where high temperatures, chemical exposure, wear, and dimensional precision are involved.

As a result, many manufacturers are turning to PEEK machined components for critical applications where long-term reliability and high performance are essential.

PEEK (Polyether Ether Ketone) is widely recognised as one of the most advanced engineering thermoplastics available. Offering an exceptional balance of mechanical strength, thermal resistance, chemical inertness, and machinability, PEEK has become the material of choice across industries such as aerospace, semiconductor, medical, and oil & gas.

What is PEEK?

PEEK is a semi-crystalline high-performance thermoplastic belonging to the polyaryletherketone (PAEK) family. It has been specifically developed for applications where standard engineering plastics are unable to provide sufficient mechanical or thermal performance.

PEEK combines the processability of thermoplastics with performance characteristics approaching that of certain metals, making it one of the most versatile materials available to design engineers.

Typical properties of PEEK include:

• Continuous operating temperatures up to 250°C 
• Excellent mechanical strength and stiffness 
• Outstanding wear and abrasion resistance 
• Exceptional chemical resistance 
• Low moisture absorption 
• Excellent dimensional stability  

Because of this combination of properties, PEEK is frequently used as a lightweight, corrosion-resistant alternative to metal in demanding engineering environments.

Why OEMs Choose PEEK Machined Components

Exceptional Mechanical Strength

PEEK possesses one of the highest strength profiles of any thermoplastic commonly available for machining.

Typical Mechanical Properties of PEEK

Tensile Strength: 90–100 MPa
Compressive Strength: 120–140 MPa
Flexural Modulus: 3.5–4.2 GPa
Hardness: Rockwell M99

This allows machined PEEK components to withstand substantial structural and mechanical loads while maintaining dimensional integrity under stress.

For OEMs, this provides:

• Reduced deformation under load 
• Improved creep resistance 
• Greater long-term reliability in structural applications  

Outstanding Temperature Resistance

One of the primary reasons OEMs specify PEEK is its ability to retain mechanical properties at elevated temperatures.

Typical Thermal Properties of PEEK

Continuous Service Temperature: 250°C
Short-Term Peak Temperature: 300°C+
Melting Point: 343°C
Glass Transition Temperature: 143°C

Unlike many engineering plastics, which soften significantly as temperatures rise, PEEK retains much of its strength and rigidity even in high-temperature operating environments.

This makes it ideal for:

• Aerospace systems 
• Semiconductor processing equipment 
• Automotive under-bonnet applications 
• Industrial heating equipment  

Excellent Chemical Resistance

PEEK exhibits excellent resistance to a broad range of chemicals including:

• Hydrocarbons 
• Organic solvents 
• Acids 
• Alkalis 
• Steam and hot water  

This makes PEEK particularly valuable in environments where chemical exposure would rapidly degrade other polymers or metallic materials.

Superior Wear and Bearing Performance

PEEK offers excellent tribological properties, making it highly suitable for dynamic wear applications.

Typical PV Values

Virgin PEEK: 0.50–0.70 MPa·m/s
Bearing Grade PEEK: 1.5–3.0 MPa·m/s
PTFE: 0.25–0.50 MPa·m/s

This enables PEEK to be used effectively in:

• Bearings 
• Bushings 
• Valve seats 
• Compressor rings 
• Wear pads  

Excellent Dimensional Stability and Precision Machinability

Many OEM applications require tight dimensional tolerances and consistent repeatability. PEEK machines exceptionally well compared to softer polymers due to its rigidity and structural stability.

Typical Machining Tolerances

Turned Components: ±0.02 mm
Milled Features: ±0.03 mm
Precision Features: ±0.01 mm (special applications)

This makes PEEK highly suitable for:

• Precision instrumentation 
• Semiconductor tooling 
• Aerospace assemblies 
• Medical devices  

Why OEMs Prefer Machined PEEK Components Over Molded Parts

While PEEK can be injection molded, many OEMs choose machining as their preferred manufacturing process for several reasons.

Lower Tooling Costs

Machining eliminates the need for expensive injection mould tooling, making it ideal for low to medium production volumes.

Faster Development Cycles

Machined parts can be manufactured directly from stock shapes, allowing for rapid prototyping and shorter lead times.

Higher Precision

Machining often allows for tighter tolerances and improved dimensional control compared to moulded parts.

Greater Design Flexibility

Complex geometries can be modified without requiring new tooling, reducing development costs during design iterations.

Although machining remains the most common route, certain high-volume parts need to be injection molded. In such cases, the tool cost is more that covered by the saving on raw materials – especially since PEEK is an expensive polymer. However, molding is tricky and needs to be done in a special purpose machine designed to handle both the temperatures as well as the corrosive nature of molten PEEK. It should be mentioned that using a regular machine to mold PEEK will almost certainly result in damage to the screw barrel, as PEEK in liquid form corrodes most ordinary metals very effectively.

Industries That Commonly Use PEEK Machined Components

Aerospace

PEEK is widely used in aerospace applications due to its excellent strength-to-weight ratio, flame resistance, and thermal performance.

Typical applications include:

• Structural brackets 
• Bearing cages 
• Cable supports 
• Electrical insulators  

Semiconductor

PEEK’s purity, thermal stability, and chemical resistance make it ideal for semiconductor manufacturing equipment.

Typical applications include:

• Wafer handling components 
• Vacuum chamber fixtures 
• Insulators 
• Wet process tooling  

Medical

Medical OEMs value PEEK for its sterilisation resistance, biocompatibility, and X-ray transparency.

Typical applications include:

• Surgical device components 
• Dental tooling 
• Analytical instrument parts  

Oil & Gas

PEEK performs exceptionally well in harsh oil and gas environments.

Typical applications include:

• Backup rings 
• Valve seats 
• Compressor components  

PEEK Compared to Other Engineering Plastics

Property Comparison

Although PEEK carries a higher upfront material cost than many engineering plastics, OEMs often justify this through:

• Longer component life 
• Reduced maintenance 
• Improved reliability 
• Lower total lifecycle cost

Design Considerations When Specifying PEEK Components

When designing PEEK machined parts, several factors should be considered:

Grade Selection

PEEK is available in multiple grades including:

• Virgin PEEK 
• Glass Filled PEEK 
• Carbon Filled PEEK 
• Bearing Grade PEEK  

Each offers unique performance advantages depending on the application. The exact composition of the material can be further altered to match the end-application requirements.

Thermal Expansion

Although lower than most plastics, PEEK still exhibits greater thermal expansion than metals and should be accounted for in design.

Machining Expertise

Due to the relatively high cost of PEEK raw material, working with an experienced machining partner is critical to minimise waste and ensure precision.

Conclusion

PEEK machined components have become an increasingly important solution for OEMs designing products for critical applications. Their outstanding strength, temperature resistance, wear performance, chemical resistance, and dimensional stability make them one of the most capable engineering materials available.

Whether replacing metal to reduce weight, improving durability in harsh chemical environments, or developing components for elevated temperature applications, PEEK offers a level of performance unmatched by most conventional plastics.

For OEMs seeking precision, reliability, and long-term performance, PEEK machined components remain one of the most effective material solutions available.

Read More

1. Polyphenylene Sulfide (PPS) in Vacuum Systems: A High-Performance Alternative to Metals

2. 5 Places Where High-Performance Polymers Replace Metals in Semiconductor Equipment

3. High-Performance Polymer Components for the Semiconductor Industry: PEEK, PPS, and Polyimide