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- Extreme Temperature Processing: PEEK requires melt temperatures of 350-400°C and mold temperatures of 160-200°C, demanding specialized equipment and precise control.
- Superior Material Properties: The resulting parts exhibit exceptional mechanical strength (up to 100 MPa tensile strength), chemical resistance, and a high heat deflection temperature, reaching 315°C for glass-filled grades.
- Critical Material Handling: PEEK is hygroscopic and must be dried for 3-4 hours at 150-160°C before processing to prevent defects. Improper drying is a primary cause of part failure.
- Hoch injection molding cost & Complexity: The raw material is 50-100 times more expensive than standard plastics like ABS, and longer cycle times (25-50% more) contribute to higher overall production costs.
What Is Peek Injection Molding?
PEEK injection molding is a specialized manufacturing process used to shape Polyetheretherketone thermoplastic into complex, high-performance parts — requiring melt temperatures between 350°C and 400°C. This process leverages the principles of traditional injection molding but adapts them for the extreme processing window of PEEK, a semi-crystalline, high-performance engineering polymer. In our factory in our facility, we’ve found that mastering PEEK requires more than just high-temperature machines; it demands a deep understanding of the material’s relationship with thermal dynamics to control its crystallinity1 and final properties. The difference between a robust, dimensionally stable PEEK component and a brittle, warped failure often lies in precise control over mold temperature and cooling rates.
| Eigentum | PEEK | Nylon 66 | PPS |
|---|---|---|---|
| Max use temp | 250°C | 120°C | 200°C |
| Chemical resistance | Ausgezeichnet | Mäßig | Ausgezeichnet |
| Tensile strength | 100 MPa | 70–80 MPa | 80–90 MPa |
For complete process guidance, see our injection molding complete guide1 and our injection mold complete guide2.
Unlike commodity plastics, PEEK’s processing is unforgiving. Its high melting point (around 343°C) necessitates equipment with ceramic heater bands, specialized screw and barrel materials (like bimetallic or nickel-based alloys) to withstand the corrosive and abrasive nature of the melt, and advanced mold temperature controllers. Our 20 years of experience have taught us that every stage, from material drying to post-mold annealing, is critical. We utilize dedicated high-temperature presses from our fleet of 45 machines, ensuring that the entire thermal chain—from the dryer to the nozzle to the mold cavity—is maintained with unparalleled precision to produce parts that meet the stringent demands of the aerospace, medical, and automotive industries.
PEEK requires mold temperatures exceeding 160°C for optimal crystallinity.Wahr
To achieve the desired semi-crystalline structure that gives PEEK its superior mechanical and chemical properties, the mold must be maintained between 160°C and 200°C. A cold mold causes the polymer to solidify too quickly in an amorphous state, resulting in brittle parts with poor performance.
PEEK can be processed using standard molding machines without modification.Falsch
Standard machines typically max out around 300°C. PEEK requires barrel temperatures of 350-400°C and robust mold heating systems, necessitating specialized machines with high-temperature heater bands, corrosion-resistant screws, and advanced thermal controllers.
How Does Peek Injection Molding Work?
PEEK injection molding works by melting the raw polymer and injecting it into a mold under high pressure — a process involving 4 key stages: material preparation, melting and injection, packing and cooling, and ejection and post-processing. Each stage is adapted to handle PEEK’s unique high-temperature characteristics and sensitivity to moisture. Failure to execute any stage perfectly can compromise the final part’s integrity, a costly mistake given the material’s price.
1. Material Preparation (Drying): PEEK is hygroscopic2, meaning it absorbs moisture from the air. Before molding, pellets must be dried in a desiccant dryer for 3 to 4 hours at 150-160°C. In our facility, we verify moisture content is below 0.02% to prevent hydrolysis during melting, which would degrade the polymer chains and cause splay marks or brittleness.
| Parameter | PEEK Range |
|---|---|
| Schmelztemperatur | 350–400°C |
| Temperatur der Form | 160–200°C |
| Einspritzdruck | 140–200 MPa |
| Pre-drying | 150°C / 3–4 h |
2. Melting and Injection: The dried pellets are fed into the barrel of a specialized injection molding machine. The reciprocating screw melts and homogenizes the PEEK at 350-400°C. The screw then injects the molten polymer into the mold cavity under high pressure, typically 100-150 MPa, to ensure complete filling of complex geometries.
3. Packing, Holding, and Cooling: Once the cavity is filled, a “packing” or “holding” pressure is applied to compensate for material shrinkage as it cools. This is the most critical phase for PEEK’s properties. The mold is held at a very high temperature (160-200°C) to allow the polymer chains to arrange into an ordered, crystalline structure. This slow, controlled cooling is essential for achieving maximum strength, stiffness, and chemical resistance.
4. Ejection and Post-Processing (Annealing): After solidifying, the part is ejected. For many high-precision applications, an additional post-molding step called annealing3 is required. This involves heating the part in an oven in a controlled cycle to relieve internal stresses built up during molding, which further enhances dimensional stability and mechanical performance.
What Are the Key Processing Parameters?
The key processing parameters for PEEK are a precise set of thermal and pressure settings critical for part quality — including a mold temperature of 160-200°C, an injection pressure of 100-150 MPa, and a melt temperature up to 400°C. These parameters are far less forgiving than those for commodity plastics and must be tightly controlled within a narrow window to manage crystallinity and prevent defectour team facility, we develop a unique process sheet for every PEEK project, as even minor variations in part geometry can require adjustments to this sensitive thermal and pressure balance.
The table below outlines the typical processing window we use as a starting point for molding unfilled PEEK grades. It’s important to note that glass or carbon-filled grades may require adjustments, often to injection pressure and screw speed, to prevent fiber breakage.
| Parameter | Value / Range | our Technical Notes |
|---|---|---|
| Drying Temperature & Time | 150°C – 160°C for 3-4 hours | Mandatory to prevent hydrolysis. We recommend verifying moisture content is <0.02% with a moisture analyzer. |
| Schmelztemperatur | 350°C – 400°C | Set progressively from rear to front zone. Nozzle temperature must be maintained diligently; a cold nozzle will cause freeze-off. |
| Temperatur der Form | 160°C – 200°C | The most critical parameter for controlling crystallinity. Use oil or high-pressure water for stable thermal control. Below 143°C (Tg), the part will be amorphous and brittle. |
| Einspritzdruck | 100 MPa – 150 MPa | High pressure is needed to push the viscous melt into the cavity. Must be balanced with injection speed to avoid shear burning. |
| Gegendruck | 5 MPa – 10 MPa | Essential for ensuring a consistent melt density and removing any trapped volatiles. Too high can cause material degradation. |
| Schneckendrehzahl | 40 – 80 RPM | A lower screw speed is preferred to minimize shear heat generation, which can degrade the PEEK polymer. |
| Venting Depth | 0.02 mm | Crucial for allowing trapped air to escape the cavity, preventing gas traps and burn marks. PEEK’s low viscosity when molten requires tight vents. |
Mastering these parameters is a core competency in our facility. For example, the relationship between mold temperature and cooling time directly dictates the level of crystallinity. A higher mold temperature (e.g., 200°C) held for a longer duration will produce a part with maximum crystallinity, offering the best mechanical performance and chemical resistance. However, this also increases cycle time and cost. Our engineers balance these factors to meet the specific performance and budget requirements of each client’s application, leveraging our 20 years of material science expertise across over 400 different polymers.
What Are the Advantages and Disadvantages?
The advantages and disadvantages of PEEK molding represent a trade-off between extreme performance and processing complexity — offering a tensile strength of up to 100 MPa but at a material cost 50 to 100 times higher than ABS. While PEEK provides unparalleled performance in harsh environments, its high cost and demanding processing requirements mean it is reserved for applications where no other material will suffice. In our experience, clients choose PEEK when component failure is not an option, whether in a human body, an aircraft engine, or a downhole drilling operation.
The decision to use PEEK must be made with a full understanding of its profile. We often consult with clients to determine if a less expensive high-performance polymer, like PEI or PPS, could meet their needs. However, when the application demands the absolute peak of polymer performance, PEEK is the undisputed choice.
| Advantages (Pros) | Disadvantages (Cons) |
|---|---|
| Exceptional Thermal Stability: Can operate continuously at temperatures up to 260°C and has a high heat deflection temperature (315°C for filled grades). | Extremely High Material Cost: Raw PEEK resin can be 50-100 times more expensive than standard engineering plastics like ABS or Polycarbonate. |
| Outstanding Mechanical Strength: High tensile strength (90-100 MPa), stiffness, and excellent fatigue and creep resistance, even at elevated temperatures. | Difficult and Demanding Processing: Requires specialized high-temperature equipment (400°C melt, 200°C mold) and precise process control. |
| Superior Chemical & Hydrolysis Resistance: Virtually inert to a wide range of organic and inorganic chemicals, steam, and hot water. | High Shrinkage & Warpage Potential: The transition from amorphous to crystalline state causes significant shrinkage (1.2-2.4%), requiring expert Spritzgussformdesign to manage warpage. |
The following rows continue the comparison:
| Biokompatibilität: Certain grades are ISO 10993 compliant, making them suitable for medical implants and surgical instruments. | Longer Cycle Times: The need for high mold temperatures and controlled cooling extends cycle times by 25-50% compared to other polymers, increasing manufacturing cost. |
| Inherent Flame Retardancy: Low smoke and toxic gas emission when exposed to flame (UL94 V-0 rated). | Requires Post-Processing (Annealing): For tight-tolerance parts, annealing is often necessary to relieve internal stresses, adding an extra step and cost to production. |
What Are the Common Defects and How to Prevent Them?
Common defects in PEEK molding are specific flaws like warpage, voids, and splay marks that arise from improper process control — often preventable by ensuring drying for at least 3-4 hours at 150°C and maintaining precise temperature profiles. Due to PEEK’s high cost and semi-crystalline nature, preventing these defects at the source is far more critical than with other materials. A single rejected batch can represent a significant financial loss. In our facility, our process engineers and quality control teams work in tandem, using process monitoring and part inspection to catch and correct deviations before they lead to defects.
Understanding the root cause is key to prevention. For instance, warpage is not just a cooling issue; it’s a crystallinity management issue. If one area of the part cools faster than another, it will have a different crystalline structure, leading to internal stresses that physically distort the part. Our expertise lies in designing molds with sophisticated cooling channels and defining processing parameters that promote uniform crystallinity across the entire part geometry.
PEEK’s material shrinkage can be as high as 2.4%.Wahr
Unfilled PEEK has a high mold shrinkage rate of 1.2% to 2.4%, which is a primary cause of warpage and dimensional instability. This must be accounted for in mold design, and fiber-filled grades are often used to reduce shrinkage for tight-tolerance parts.
Annealing PEEK parts is an optional step for non-critical applications.Falsch
While a part may seem acceptable post-molding, internal stresses can lead to cracking or warping over time, especially under thermal or mechanical load. Annealing is a critical step to relieve these stresses and ensure long-term dimensional stability and performance for almost all PEEK applications.
| Defekt | Primary Cause(s) | Prevention Strategy in our facility |
|---|---|---|
| Warpage / Distortion | Non-uniform cooling; differential shrinkage due to inconsistent crystallinity. Thick and thin sections cooling at different rates. | Design molds with strategic cooling lines. Maintain a high, uniform mold temperature (160-200°C). Optimize part design to have uniform wall thickness. |
| Splay Marks / Silver Streaks | Moisture in the material. The water turns to steam at PEEK’s high melt temperature, causing visual streaks on the part surface. | Strict adherence to drying protocols: 150-160°C for 3-4 hours in a desiccant dryer. Verify moisture content is below 0.02%. |
| Internal Voids / Porosity | Insufficient packing pressure; material shrinkage in thick sections; trapped gas. | Increase holding pressure and time to compensate for shrinkage. Ensure adequate venting (0.02 mm). Design parts to avoid very thick cross-sections or use gas-assist molding. |
Additional defects and their prevention strategies:
| Defekt | Primary Cause(s) | Prevention |
|---|---|---|
| Burn Marks / Discoloration | Material degradation from excessive temperature or residence time in the barrel. Trapped air auto-igniting under pressure (Dieseling). | Optimize barrel temperature profile. Reduce screw speed to minimize shear heat. Ensure proper mold venting. Purge barrel if machine is idle. |
| Short Shots / Incomplete Fill | Insufficient injection pressure or speed; melt freezing off prematurely; undersized gates or runners. | Increase injection pressure/speed. Raise melt or mold temperature. Use large, full-round runners and appropriately sized gates (direct, tab, or fan) for better flow. |
Where Is Peek Injection Molding Used?
PEEK injection molding is used in industries requiring components that withstand extreme environments — with major applications in aerospace, medical, and automotive sectors where temperatures can exceed 300°C. Its unique combination of light weight, high strength, and resistance to chemicals and wear makes it an ideal replacement for metals like aluminum, stainless steel, and even titanium in specific contexts. The ability to mold PEEK into
complex, net-shape parts reduces the need for secondary machining, offering a manufacturing advantage for intricate components.
| Industrie | Example Applications | Reason for Using PEEK |
|---|---|---|
| Aerospace & Defense | Engine components, electrical connectors, thermal acoustic insulation, structural brackets, radomes. | High strength-to-weight ratio, thermal stability (operates in hot engine areas), flame retardancy (low smoke/toxicity), chemical resistance to jet fuel and hydraulic fluids. |
| Medical & Healthcare | Spinal fusion cages, trauma fixation devices, dental implants, surgical instruments, sterilization trays. | Biocompatibility (ISO 10993 grades), radiolucency (clear on X-rays), resistance to repeated sterilization cycles (steam, gamma, EtO), high strength for load-bearing implants. |
| Automobilindustrie | Thrust washers, seal rings, bearings in transmissions, ABS sensor components, electric motor insulation. | Excellent wear and friction properties, resistance to automotive fluids (oils, fuels), high-temperature performance, dimensional stability for precision components. |
| Oil & Gas | Downhole electrical connectors, seals, valve seats, compressor rings, subsea components. | Extreme chemical resistance (sour gas), high-temperature and high-pressure (HTHP) stability, excellent hydrolysis resistance. |
| Semiconductor & Electronics | Wafer handling tools, CMP rings, test sockets, high-frequency insulators. | High purity, dimensional stability at high temperatures, excellent dielectric properties, resistance to harsh cleaning chemicals. |
How Does Peek Injection Molding Compare to Alternatives?
PEEK injection molding compares to alternatives like PEI (Ultem) and PPS by offering superior overall performance — featuring a higher heat deflection temperature of 315°C for glass-filled grades, albeit at a significantly higher cost. The choice between these high-performance polymers is not about which is “best,” but which is “right” for the specific application’s cost and performance requirements. As a manufacturer with experience in over 400 materials, our team guides clients to the most effective material solution.
For example, while PEEK has the highest temperature resistance and mechanical strength, PEI (Ultem) offers excellent performance at a lower price point, making it a great choice for applications that don’t push the absolute limits of thermal or chemical exposure. PPS, on the other hand, provides exceptional chemical resistance that can sometimes surpass PEEK against specific aggressive chemicals, but with lower toughness. The comparison below highlights these critical trade-offs.
| Merkmal | PEEK (Polyetheretherketone) | PEI (Polyetherimide / Ultem) | PPS (Polyphenylensulfid) |
|---|---|---|---|
| Max Continuous Use Temp. | ~260°C | ~170°C | ~220°C |
| Tensile Strength (Unfilled) | ~90-100 MPa | ~105 MPa | ~80 MPa |
| Chemische Beständigkeit | Excellent (except concentrated sulfuric acid) | Good (vulnerable to some chlorinated solvents) | Excellent (one of the most resistant polymers) |
| Verarbeitungstemperatur | Very High (350-400°C melt) | High (300-340°C melt) | High (300-330°C melt) |
| Relative Cost | Very High (Baseline) | High (~40-60% of PEEK’s cost) | Medium-High (~25-40% of PEEK’s cost) |
| our Application Note | Use for peak performance: medical implants, aerospace, HTHP environments where failure is not an option. | Use for high-temp applications with cost constraints: electrical connectors, reusable medical trays, automotive components. | Use when ultimate chemical resistance is the primary driver and high impact strength is secondary: pumps, valves, fuel system parts. |
Factory Insight: PEEK Injection Molding at ZetarMold
In our Shanghai facility, we process peek injection molding across 45 machines (90T–1850T) with 20+ years of engineering thermoplastic experience. PEEK requires specialized high-temperature barrel and mold equipment (350–400°C melt temperature); we run PEEK programs on dedicated machines to avoid cross-contamination with standard resins. With 400+ materials processed and 100+ molds per month, our team of 8 senior engineers and 120+ production staff has encountered the full range of processing challenges for this material class. Our standard approach is to run a qualification program before production starts, establishing process windows that account for material lot variation and ambient condition changes.
Häufig gestellte Fragen
What is PEEK injection molding?
PEEK injection molding is a high-temperature manufacturing process that melts Polyetheretherketone resin at 350-400°C and injects it into a mold to create durable, high-performance components. The process requires specialized machinery capable of handling the extreme temperatures and pressures needed to process this advanced polymer and control its crystalline structure for optimal properties.
What temperature is used for PEEK injection molding?
PEEK injection molding uses a very specific and high-temperature profile. The melt temperature in the machine’s barrel is typically between 350°C and 400°C. Critically, the mold itself must be heated to a range of 160°C to 200°C to ensure the part cools slowly, allowing for proper crystallization.
What are the properties of PEEK plastic?
PEEK plastic is known for its exceptional properties, including high-temperature resistance (up to 260°C continuous use), excellent mechanical strength with a tensile strength of 90-100 MPa, superior chemical and hydrolysis resistance, and inherent flame retardancy. Certain grades are also biocompatible, making them suitable for medical implants.
What are the applications of PEEK injection molding?
PEEK injection molding is used for mission-critical applications in demanding industries. Key sectors include aerospace (engine parts, brackets), medical (spinal implants, surgical tools), automotive (transmission components, bearings), and oil & gas (seals, connectors for high-pressure, high-temperature environments).
Why is PEEK injection molding expensive?
PEEK injection molding is expensive for two main reasons. First, the raw material cost is 50 to 100 times higher than commodity plastics. Second, the process requires specialized, expensive machinery, high energy consumption for heating, and longer cycle times (often 25-50% longer) due to the controlled cooling phase, all of which increase the final part cost.
What are the challenges of PEEK injection molding?
The main challenges are managing its extreme processing window and high cost. This includes precisely controlling melt temperatures up to 400°C and mold temperatures up to 200°C, managing a high shrinkage rate (up to 2.4%) to prevent warpage, and ensuring the material is perfectly dry (below 0.02% moisture) to prevent degradation during processing.
What is the difference between PEEK and PEK?
PEEK (Polyetheretherketone) and PEK (Polyetherketone) are both in the PAEK family, but PEK has a higher ratio of ketone to ether links. This gives PEK a slightly higher glass transition temperature (Tg) and melting point, making it marginally more stable at extreme temperatures than PEEK. However, PEEK is generally tougher, more widely available, and easier to process, making it the more common choice for most applications.
With 20+ years of experience, we have been at the forefront of injection molding, transforming the most challenging engineering polymers into precision components. Our mastery of PEEK is not just about having the right equipment; it’s about two decades of accumulated knowledge, process refinement, and a deep understanding of material science. With a fleet of 45 advanced injection molding machines and hands-on experience with over 400 material grades, we possess the expertise to navigate the complexities of PEEK molding—from mold design and process optimization to post-mold annealing.
We understand that choosing PEEK is a significant investment in performance and reliability. Our team of engineers is ready to partner with you, providing the technical guidance needed to ensure your components meet the most stringent specifications while optimizing for manufacturing efficiency. If you are developing a product that demands the ultimate in thermal, mechanical, and chemical performance, contact us today to leverage our expertise and bring your design to life.
1 Crystallinity: The degree of structural order in a polymer. In semi-crystalline polymers like PEEK, ordered molecular chains form crystalline regions, which impart stiffness, strength, and chemical resistance, while disordered chains form amorphous regions. ↩
2 Hygroscopic: The tendency of a material to absorb moisture from the surrounding air. For molding plastics, this is a critical property as absorbed water can turn to steam at processing temperatures, degrading the material and causing defects. ↩
3 Glühen: A heat treatment process where a material is heated to a specific temperature below its melting point, held for a set duration, and then slowly cooled. In polymers, this relieves internal stresses locked in during molding, improving dimensional stability and mechanical properties. ↩
Ready to start a PEEK injection molding program? Contact us or explore our Spritzgießen3 for engineering thermoplastic expertise.
Bottom line: PEEK is an extreme-performance resin that costs 20–50× commodity plastics and requires specialized barrel and mold equipment. It’s the right answer when no other material meets the temperature, chemical, or structural requirement—not a prestige upgrade. Process it at 350–400°C melt with 160–200°C mold temperature, dry at 150°C for 4 hours, and run dedicated equipment to avoid cross-contamination. If your application can be served by PPS, nylon 46, or PEEK/CF blends at lower cost, that’s worth evaluating first.
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injection molding: A manufacturing process where molten thermoplastic is injected under pressure into a closed mold cavity, cooled, and ejected as a finished part. Used for high-volume production of complex geometries in commodity and engineering thermoplastics. ↩
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mold design: The engineering process of creating injection mold tooling, including cavity/core geometry, cooling circuit layout, gating system, and ejection mechanism. Mold design directly determines part quality, cycle time, and tooling cost. ↩
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term 3: A key concept in injection molding manufacturing and tooling. ↩
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