PEEK injection molding service

Custom peek injection molding project with LTC Plastic, with design and engineering support, OEM, ODM, mold making, and post-finishing support.

Polyether ether ketone (PEEK) injection molding is now recognised as one of the most advanced plastic injection molding methods for producing high-performance components across aerospace, medical, automotive, electronics, and industrial sectors. As engineering requirements push toward higher temperatures, tougher chemicals, and ultra-tight tolerances.

PEEK has become the preferred polymer for mission-critical projects. Its stability, strength, and precision make it ideal for complex mold and mould designs that demand long-term reliability.

This pillar page will take you step-by-step through everything you need to know about PEEK injection molding—from material properties and application advantages to tooling design, PEEK molding process parameters, injection molding machine setup, and best practices for producing consistent PEEK molded parts.

You’ll also learn key considerations for handling high-temperature resin, optimizing part geometry, selecting the right machine, and ensuring smooth PEEK polymer injection throughout production.

Whether you are developing a brand-new PEEK component or enhancing an existing design, this comprehensive guide provides the technical clarity and practical insight you need to succeed with PEEK and achieve reliable, repeatable results in every plastic part you manufacture.

What Is PEEK? Understanding the High-Performance Engineering Polymer

PEEK (Polyether Ether Ketone) is part of the polyaryletherketone (PAEK) family—one of the strongest, most chemically resistant, and thermally stable engineering thermoplastics available today.

As a semi-crystalline thermoplastic, this high-performance PEEK resin is designed for extreme environments where traditional plastics and even many metals fail. Its outstanding stability makes it a preferred PEEK high-temperature plastic for aerospace, automotive, medical, and industrial applications.

Key Characteristics of PEEK

• High temperature resistance up to 260°C for continuous use, suitable for the demanding injection molding process and tight processing temperature control.
• Exceptional mechanical properties comparable to light metals, enabling strong and reliable injection molded PEEK components.
• Chemical resistance to acids, solvents, oils, and fuels, ideal for harsh-environment plastic parts.
• Superior wear and abrasion resistance, supporting long-life PEEK parts in dynamic assemblies.
• Low smoke and low toxicity, meeting strict aerospace requirements.
• Dimensional stability under load and temperature cycling, critical for precision PEEK component manufacturing.
• Outstanding fatigue resistance, making it suitable for repeated stress applications.
• Biocompatibility options for medical and dental markets.

These characteristics make PEEK ideal for precision molding applications. With proper mold temperature and strict PEEK mold temperature requirements, manufacturers can efficiently achieve complex geometries when molding PEEK. Its flow behaviour and stability allow the production of highly reliable injection-molded components, ensuring consistent performance in every advanced plastic design using this exceptional PEEK material.

Why Choose PEEK Injection Molding?

PEEK injection molding offers a powerful way to maximize the performance advantages of polyetheretherketone, combining precision with cost-effective scalability.

This manufacturing process is especially effective for high-performance applications in aerospace, medical, electronics, and industrial sectors where chemical resistance, strength, and dimensional stability are essential. It also supports a wide range of materials, including unfilled PEEK resin, glass-filled PEEK molding, and carbon-fiber reinforced PEEK.

1. Precision for Complex Geometries

As a semi-crystalline, high-temperature thermoplastic with a high melting point, PEEK flows exceptionally well during the PEEK material processing stage. This enables accurate reproduction of thin walls, micro-features, and tight tolerances—ideal for high-precision aerospace PEEK parts and medical device components.

2. Consistent Part Quality

Injection molding delivers exceptional consistency through controlled PEEK injection molding parameters such as temperature, pressure, and cooling rates. This ensures:

even material distribution
reduced internal stress
predictable shrinkage
strong dimensional repeatability for large production runs

These advantages are crucial for medical-grade PEEK molding, surgical tools, and implant components where biocompatibility and reliability are mandatory.

3. High Strength-to-Weight Ratio

PEEK offers metal-like strength at a fraction of the weight. Reinforced grades—such as carbon fiber or glass-filled variants—further enhance stiffness and insulation performance, making molded parts ideal for extreme environments.

4. Scalability

Once the mold is built, injection molding significantly reduces per-unit cost compared with machining, especially for medium- to high-volume production.

5. Integration of Multiple Functions

PEEK molding allows manufacturers to consolidate assemblies by incorporating ribs, clips, bosses, undercuts, inserts, and other features directly into the part. This supports efficient metal-to-plastic replacement and improves overall performance and durability.

Understanding the PEEK Injection Molding Process

PEEK is not molded like ordinary plastics. PEEK plastic injection molding requires strict temperature control, precise mold design, and specialized equipment capable of handling extremely high heat and pressure. Because PEEK polymer is a high-performance material with exceptional strength, the entire workflow must be optimized to produce reliable, repeatable, and dimensionally stable PEEK components across any grade of PEEK, including unfilled PEEK and reinforced variants.

Step-by-Step Process

1. Material Preparation

Before entering the PEEK injection molding process, all PEEK plastic must be thoroughly dried to prevent hydrolysis and surface defects.
Typical PEEK drying temperature settings:

150°C for 3–4 hours
Moisture content < 0.02%

Proper drying preserves key properties of PEEK, such as chemical resistance, strength, and fatigue performance.

2. Plasticizing and Melting

PEEK has a melting point near 343°C, and the recommended PEEK melt temperature during processing typically ranges from 370°C to 420°C. Only high-temperature-capable injection molding machines are suitable for handling this high-performance thermoplastic.

3. Injection Phase

During injection, the molten material is pushed into the mold cavity at extremely high injection pressure to guarantee complete filling and proper crystallization.
Typical pressure range: 100–200 MPa, depending on part geometry and the selected grade of PEEK.

Injection speed must also be adjusted to avoid flow marks and ensure uniform packing—critical for achieving durable injection molded PEEK parts such as PEEK wear-resistant parts and chemical-resistant PEEK components.

4. Packing and Holding

Precise holding pressure is essential for:

maintaining consistent crystallinity
reducing shrinkage
ensuring dimensional accuracy
preventing internal stress

This step is key to producing stable, high-precision peek components.

5. Cooling

Cooling channels must be carefully engineered in the mold design to avoid hot spots and maintain optimal crystallinity.
Typical mold temperature: 160–200°C.

6. Ejection

Once solidified, the parts are ejected. Because PEEK is tough and abrasive, controlled ejection prevents stress marks, cracking, or deformation—ensuring final parts meet strict performance requirements.

Material Grades for PEEK Injection Molding

PEEK is offered in a wide range of filled and unfilled grades, each engineered to meet different performance needs. Selecting the proper PEEK resin is one of the key factors to consider, as it directly influences stiffness, flow behaviour, surface finish, and compatibility with high processing temperatures during molding. As a high-performance thermoplastic, PEEK delivers exceptional strength and wear resistance, but each grade provides unique advantages.

Unfilled PEEK

Best flow characteristics
Excellent for thin-wall geometries
Highest surface finish quality
Suitable for electronics and precision parts for use in medical applications

This grade offers balanced performance and is the easiest to mold due to its smooth flow at high processing conditions.

Increased rigidity and stiffness
Improved dimensional stability
Ideal for structural or load-bearing components

Glass-filled PEEK is preferred when mechanical strength must be increased without significantly compromising processability.

30% Carbon-Filled PEEK

Highest mechanical strength
Superior wear resistance and low friction
Recommended for bearings, bushings, and high-load industrial applications

Carbon-filled grades are ideal for demanding environments requiring maximum strength-to-weight performance.

PEEK With Additives

Lubricated grades for lower friction
Medical-use and biocompatible grades compliant with ISO 10993
FDA-approved options for food and processing equipment

These specialized grades support industry-specific requirements while maintaining the inherent advantages of PEEK as a high-performance thermoplastic.

Advantages of PEEK Over Other High-Performance Plastics

PEEK stands out among advanced engineering materials such as PPS, PI, PEI (Ultem), and PAI. During the injection process, its superior stability, strength, and temperature control capabilities give it a clear performance advantage.

Whether working with PEEK pellets or specialized reinforced formulations, manufacturers find that processing PEEK delivers a unique balance of durability, chemical resistance, and precision not matched by other high-performance plastics.

Comparison Overview

Property	PEEK	PPS	Ultem (PEI)	PAI
Temperature resistance	★★★★★	★★★	★★★★	★★★★★
Chemical resistance	★★★★★	★★★★	★★	★★★
Mechanical strength	★★★★★	★★★	★★★★	★★★★★
Machinability	★★★★	★★	★★★	★★
Wear resistance	★★★★★	★★★	★★	★★★★★

PEEK consistently offers the strongest overall performance across critical categories. Its combination of thermal stability, chemical resistance, strength, and wear behaviour allows it to outperform competing materials in severe operating conditions. This exceptional balance makes PEEK the preferred material for components requiring long service life, precision molding, and reliable performance even under extreme environmental or mechanical stress.

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Applications of PEEK Injection Molding Across Industries

With its exceptional material properties, polyether ether ketone (PEEK) has become one of the most important engineering plastic options for high-performance manufacturing. Because PEEK is a semi-crystalline polymer with excellent mechanical properties, chemical resistance, and the ability to endure extreme environments, it is widely used for molded parts across multiple advanced sectors.

Proper PEEK mold design considerations, control of PEEK part shrinkage, and managing PEEK warpage issues allow manufacturers to achieve highly accurate, reliable components in every field.

Aerospace and Aviation

In aerospace, PEEK frequently replaces aluminum and titanium in non-structural components. Common PEEK industrial applications include:

clips, brackets, and fasteners
insulation components
high-temperature engine parts

Because PEEK can withstand continuous heat and offers low smoke and toxicity, it is ideal for aircraft interior parts.

Medical and Dental

In medical applications, PEEK offers biocompatibility, stability, and metal-free performance. Typical parts include:

surgical instrument handles
dental abutments and PEEK for medical implants
orthopaedic trial devices
spinal cages
precision medical pump components

PEEK endures repeated sterilization cycles without losing performance, making it a top material for PEEK precision component molding.

Automotive

Automotive engineers rely on PEEK for:

under-hood high-temperature components
thrust washers and transmission parts
fuel system parts
sensor housings

Its ability to resist aggressive fuels and elevated temperatures makes it highly dependable.

Electronics and Semiconductors

PEEK provides low contamination and stable insulation. Common parts include:

wafer handling components
micro-precision parts
high-frequency insulators
electrical connector housings

Oil & Gas / Energy

Because Peek can withstand high pressure, high heat, and corrosive chemicals, it is ideal for:

down-hole tools
seals, bushings, and wear rings
connectors and high-temperature insulators

Proper PEEK tooling requirements ensure durability and stability even in extreme service environments.

Design Guidelines for PEEK Injection Molded Parts

PEEK is a high-performance material, but it is not forgiving. Its exceptional properties, high melting point, and strict processing demands mean that smart design is essential for producing successful PEEK components.

Compared with PEEK vs PPS injection molding or PEEK vs PEI molding, PEEK requires tighter processing parameters, advanced tooling, and careful planning. Understanding these design principles ensures smoother production and fewer PEEK processing challenges during PEEK advanced polymer processing.

1. Wall Thickness

Recommended range: 0.5 mm – 3.0 mm
Keep wall thickness uniform to maintain dimensional stability. Because PEEK is highly resistant to deformation, uneven walls may cause internal stress or incomplete filling.

2. Ribs and Bosses

Ribs should be 40–60% of the adjoining wall thickness to prevent sink marks.
Bosses require adequate draft angles and reinforcement ribs, especially for filled PEEK grades where added stiffness affects flow.

3. Corners and Radii

Avoid sharp corners. Generous radii improve flow, reduce stress concentrations, and maximize mechanical strength—critical for producing reliable, long-life parts.

4. Draft Angles

Minimum recommended draft: 1°–2°
A larger draft may be required for glass-filled or carbon-filled grades due to their abrasive nature and reduced flow compared to unfilled materials.

5. Avoid Sharp Transitions

Sudden thickness changes can trigger PEEK processing challenges such as stress buildup, voids, and warpage. Use gradual tapers or smooth transitions for stable filling and cooling.

6. Allow for Shrinkage

Typical PEEK part shrinkage:

Unfilled PEEK: 1.1–1.6%
Filled PEEK: 0.2–0.6%

Accurate shrinkage prediction is essential for tight tolerances, especially in high-precision applications where PEEK offers reliable dimensional performance.

7. Metal Inserts

Insert molding is achievable with PEEK, but inserts must be pre-heated to reduce residual stress. Proper temperature control ensures strong bonding without distortion.

With its excellent PEEK thermal stability performance, strength, and long service life, PEEK is used in aerospace, medical, and industrial parts—but only when designed with these guidelines in mind.

Tooling Requirements for PEEK Injection Molding

Mold design and material selection are critical key factors in achieving successful molding with PEEK. Because this polymer has demanding processing requirements, tooling must be engineered to handle high heat, abrasiveness, and precision necessary for high-performance injection molded products.

High-Temperature Tool Steel

The mold must withstand continuous temperatures approaching 200°C. Suitable steels include:

H13
S7
Stainless steel for corrosion-sensitive environments

These materials ensure durability and stability under advanced injection molding technology.

Surface Finishing

Glass-filled and carbon-filled PEEK are highly abrasive, requiring premium surface finishes. High-polish textures or protective coatings such as DLC help extend tool life and maintain quality in long production runs.

Gating System

Both hot and cold runner systems can be used, but they must be designed for high temperatures. Hot runners require specialized high-heat components, while cold runners must be optimized to reduce waste and maintain flow consistency.

Cooling System

Uniform mold temperature is essential for consistent crystallinity, mechanical strength, and dimensional accuracy. Conformal cooling is often recommended to manage heat effectively and support successful molding in demanding PEEK applications.

This combination of tooling precision and optimized design ensures high-quality injection-molded products when working with PEEK.

Processing Parameters for PEEK Injection Molding

PEEK’s advanced performance comes with demanding processing conditions. Unlike ordinary plastics, PEEK requires strict thermal control, precise drying, and high-pressure injection to achieve proper crystallinity and dimensional accuracy.

Because of its high melting point and semi-crystalline structure, even small parameter deviations can lead to defects such as warpage, poor strength, or incomplete filling. Understanding the correct processing window is essential for producing stable, high-quality parts and ensuring consistent manufacturing output across different machines and material grades.

Typical Processing Settings

(Values may vary depending on PEEK grade, machine capability, and part geometry)

Parameter	Typical Range
Drying temperature	150°C
Drying time	3–4 hours
Melt temperature	370–420°C
Mold temperature	160–200°C
Injection pressure	100–200 MPa
Holding pressure	60–100 MPa
Cooling time	Longer than standard plastics

These parameters help ensure proper melt flow, strong molecular bonding, and stable crystallization—essential for achieving reliable, high-performance PEEK molded parts.

Common Defects in PEEK Injection Molding and How to Prevent Them

PEEK is a semi-crystalline polymer known for its exceptional mechanical stability, PEEK creep resistance, and ability to form highly durable, fatigue-resistant parts. Its performance advantages make it ideal for demanding sectors such as aerospace, medical, and electronics.

However, because processing temperatures are extremely high and the material transitions between amorphous PEEK and crystalline structures during molding, defects can occur if parameters are not tightly controlled. Minimizing issues is also important for managing overall PEEK injection molding costs, especially when producing high-precision PEEK custom-molded components.

Below are the most common defects and practical solutions:

1. Silver Streaks
Cause: Excess moisture inside the resin.
Solution: Improve drying procedures and ensure the resin reaches the correct moisture level before molding. High-temperature drying is crucial for maintaining melt stability.

2. Warpage
Cause: Uneven cooling, non-uniform wall thickness, or poor crystallisation control.
Solution: Optimise mold temperature, improve cooling channel layout, and maintain consistent wall design to balance shrinkage.

3. Burn Marks
Cause: Trapped air or overly high melt temperature.
Solution: Enhance mold venting, adjust gating, and ensure air escapes before resin fills the cavity.

4. Short Shots
Cause: Insufficient melt flow or low injection energy.
Solution: Increase melt temperature or injection pressure and confirm that the flow path is smooth and unobstructed.

5. Flash
Cause: Mold wear, especially when molding parts with abrasive fillers.
Solution: Use hardened steel for tooling, maintain mold components regularly, and monitor clamp force to prevent overpacking.

Cost Factors in PEEK Injection Molding

PEEK has excellent mechanical, thermal, and chemical performance, making it a premium engineering material for use in aerospace, medical, and high-demand industrial applications. Because PEEK requires extremely high melt temperatures, strict environmental control, and consistent processing, the overall manufacturing cost is significantly higher than common polymers.

Understanding the major cost drivers helps teams plan budgets effectively when they need to produce PEEK components with tight tolerances and long-term reliability.

Main Cost Factors
• Material price: PEEK resin costs 10–30× more than standard plastics, and PEEK has high purity and quality requirements.
• Mold complexity: Tooling must handle elevated surface temperature and high injection pressures.
• Machine capability: Only high-temperature injection molding machines can process PEEK, increasing equipment and operating costs.
• Tolerance demands: Precision parts require slower cycles and stricter quality control.
• Filled grades: Glass- or carbon-filled PEEK accelerates tool wear and adds further maintenance cost.

How to Reduce Costs
• Simplify geometry where possible to reduce tooling and machining time.
• Use unfilled PEEK if performance allows, as it is easier to mold and less abrasive.
• Optimize gating and runner design to reduce scrap and improve flow.
• Consider multi-cavity molds when volumes justify the investment, lowering per-part cost through higher output.

Choosing the Right PEEK Injection Molding Manufacturer

Not all plastic molders can handle PEEK. Look for:

1. High-Temperature Injection Machines

Must support >400°C barrel temperature and >200°C mold temperature.

2. Experience With Engineering Thermoplastics

Prefer molders who regularly work with PEEK, Ultem, PPS, and other high-performance materials.

3. In-House Tooling Capabilities

Complex PEEK parts require precise molds and tool maintenance.

4. Strong Engineering Support

Manufacturers should help with:

DFM (Design for Manufacturability)
Material selection
Gate design
Cooling optimization

5. Advanced Quality System

Look for CMM reports, material certifications, and traceability.

6. Proven Case Studies

Experience with aerospace, medical, or automotive clients indicates reliability.

FAQs about PEEK injection molding

1. What is PEEK injection molding?
PEEK injection molding is the process of producing high-performance polyether ether ketone parts by injecting molten PEEK resin into a mold under precise temperature and pressure control.

2. What industries use PEEK molded parts?
PEEK is widely used in aerospace, medical, automotive, electronics, and industrial applications requiring chemical resistance, high temperature, and mechanical strength.

3. What are the key properties of PEEK?
PEEK offers high-temperature resistance, excellent mechanical strength, chemical stability, wear resistance, fatigue resistance, and biocompatibility for medical uses.

4. Why is PEEK considered a high-performance thermoplastic?
Its combination of chemical resistance, creep resistance, high melting point, and dimensional stability under stress makes PEEK a top engineering plastic.

5. What grades of PEEK are available?
PEEK is available as unfilled, glass-filled, carbon-filled, and specialty grades, including medical-grade PEEK for implants and biocompatible applications.

6. What is the typical processing temperature for PEEK?
The PEEK melt temperature ranges from 370–420°C, and the mold temperature is usually 160–200°C.

7. Why is drying PEEK important before molding?
PEEK is semi-crystalline and sensitive to moisture; improper drying can cause hydrolysis, surface defects, or reduced mechanical strength.

8. What are common defects in PEEK injection molding?
Defects include warpage, short shots, flash, and silver streaks, typically caused by uneven cooling, moisture, or improper processing parameters.

9. Can PEEK parts be reinforced?
Yes, glass-filled or carbon-fiber reinforced PEEK enhances stiffness, wear resistance, and dimensional stability for demanding applications.

10. Is PEEK suitable for medical implants?
Yes, medical-grade PEEK is biocompatible, sterilizable, and widely used for spinal cages, dental implants, and surgical instruments.

11. How does PEEK compare to other plastics?
PEEK outperforms PPS, PEI, and PAI in temperature resistance, chemical stability, wear resistance, and mechanical properties.

12. What are the tooling requirements for PEEK molding?
Molds require high-temperature steel, polished surfaces, precise PEEK mold design considerations, and robust cooling systems.

Conclusion

PEEK injection molding offers unparalleled thermal stability, mechanical strength, chemical resistance, and precision. As industries continue to push boundaries, PEEK has become a core material for next-generation engineering.

If your project requires:

extreme durability
resistance to heat and chemicals
tight tolerances
lightweight strength
reliable performance

Then, PEEK injection molding is one of the best manufacturing options available.

A reliable PEEK molding manufacturer will guide you through material selection, design optimization, prototyping, tooling, and full-scale production—ensuring your final parts meet the highest performance standards.

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