High-Temp 3D Printer Filament: Material and Hardware Considerations
High-temp 3D printer filaments are challenging to print, but they can be used to make vital end-use parts like automotive components.
Machines like the Stratasys Fortus 450mc can process high-temp 3D printer filament (credit: Stratasys)
As industries seek more durable and heat-resistant components, the demand for high-temp 3D printer filaments has surged. These materials offer exceptional thermal stability, mechanical strength, and chemical resistance, making them ideal for creating functional parts in aerospace, automotive, and industrial manufacturing sectors. From aircraft components to under-hood automotive parts and specialized tooling, high-temp filaments are enabling engineers to produce complex geometries with properties that rival traditionally manufactured parts.
This article looks at how the ability to 3D print with materials like PEEK, ULTEM, and PEKK is opening new avenues for rapid prototyping, custom manufacturing, and the production of end-use parts in critical applications where standard plastics fall short.
Common Heat-Resistant Filaments
3D printed PEEK filament (credit: MSNJ)
High-temperature 3D printing filaments are essential for applications requiring strength, durability, and thermal resistance. However, what counts as “high-temp” for one application may not meet requirements in another. In other words, common materials like ABS, ASA, and Polycarbonate (PC) outperform other affordable options like PLA filament in terms of heat resistance, but they are significantly less heat resistant than high-performance polymers like PEEK.
Entry-Level Options
ABS and ASA are low-cost, high-temperature materials typically used in consumer-grade 3D printers. These filaments can withstand temperatures up to around 100°C and are suitable for items like outdoor parts and automotive dash parts. Polycarbonate (PC) is a step up, offering better impact resistance and heat tolerance (around 140°C), making it suitable for more demanding uses like functional prototypes and enclosures.
These materials offer a good balance of heat resistance, printability, and accessibility. However, they are inferior to genuine high-performance polymers like PEEK and ULTEM, which offer exceptional thermal and chemical resistance. PEEK, for instance, can withstand temperatures exceeding 250°C, making it ideal for aerospace, medical, and industrial application. However, materials like PEEK are very expensive and require more advanced printers, typically costing tens or hundreds of thousands of dollars.
PEEK
Polyether Ether Ketone (PEEK) stands at the forefront of high-temperature 3D printing filaments, offering an unparalleled combination of thermal resistance, mechanical strength, and chemical inertness. This semi-crystalline thermoplastic polymer boasts a glass transition temperature of 143°C and a melting point of 343°C, allowing it to maintain its properties in extreme environments where other plastics would fail.
PEEK's exceptional heat resistance is attributed to its molecular structure, consisting of aromatic rings connected by ether and ketone linkages. This structure not only provides thermal stability but also contributes to its remarkable mechanical properties. With a tensile strength of up to 100 MPa and a Young's modulus of 3.6 GPa, PEEK rivals some metals in terms of strength-to-weight ratio.
The chemical inertness of PEEK is another standout feature, making it resistant to a wide range of solvents, acids, and hydrocarbons. This property, combined with its biocompatibility, opens up numerous applications in demanding industries.
In the aerospace sector, PEEK filament is used to produce lightweight, high-strength components that can withstand extreme temperatures and chemical exposure. Specific applications include:
Aircraft interior components such as seat backs and armrests
Ducting and cable management systems in engine compartments
Structural elements in satellite systems
Lightweight brackets and fasteners for reducing overall aircraft weight
The medical industry leverages PEEK's biocompatibility and mechanical properties for various applications:
Spinal implants and orthopedic devices
Dental implants and prosthetics[2]
Sterilizable surgical instruments
Custom-made cranial implants
PEEK's ability to be sterilized using standard methods without degradation makes it particularly valuable in medical applications. Its radiolucency also allows for clear imaging in X-rays and CT scans, facilitating post-operative monitoring.
Recommended reading: PEEK 3D Printing: Unlocking the Potential of High-Performance Polymers
ULTEM
ULTEM, also known as Polyetherimide (PEI), is a high-performance thermoplastic that has gained significant traction in the realm of high-temperature 3D printing. This amorphous polymer comes in several variants, with ULTEM 9085 and ULTEM 1010 being the most popular for additive manufacturing. Each variant offers a unique set of properties tailored to specific application requirements.
ULTEM filaments boast an impressive array of characteristics that make them suitable for demanding engineering applications. They exhibit high strength-to-weight ratios, excellent thermal stability, and remarkable chemical resistance. The glass transition temperature of ULTEM ranges from 186°C to 217°C, depending on the specific grade, allowing it to maintain its mechanical properties at elevated temperatures.
One of ULTEM's standout features is its inherent flame-retardant properties. Unlike many other plastics that require additives to achieve flame resistance, ULTEM's molecular structure naturally inhibits combustion. This characteristic makes it compliant with stringent flame, smoke, and toxicity (FST) standards.
The flame-retardant nature of ULTEM, combined with its excellent electrical insulation properties, makes it an ideal choice for various electrical applications:
Electrical connectors and sockets
Insulating components in high-voltage systems
Circuit board substrates for harsh environments[3]
Protective housings for electronic devices
ULTEM's versatility extends beyond electrical applications. Its biocompatibility and ability to withstand repeated sterilization cycles make it suitable for medical devices and food processing equipment. While PEEK may have slightly higher mechanical properties, ULTEM offers comparable performance with the added benefits of inherent flame retardancy and often at a lower cost. This balance of properties and cost-effectiveness has led to ULTEM's widespread adoption in industries ranging from aerospace and automotive to healthcare and consumer electronics.
PEKK
Polyetherketoneketone (PEKK) is another important option in the high-temperature 3D printing filament market, offering a unique set of properties that in some aspects surpass PEEK. This semi-crystalline thermoplastic belongs to the same family of high-performance polymers but boasts a modified molecular structure that imparts distinct advantages.
PEKK's molecular backbone consists of alternating ether and ketone groups, with an additional ketone group that distinguishes it from PEEK. This subtle structural difference results in a higher glass transition temperature (Tg) of approximately 160°C, compared to PEEK's 143°C. The increased Tg translates to better dimensional stability at elevated temperatures, making PEKK an excellent choice for applications requiring high heat resistance.
One of PEKK's standout features is its improved layer adhesion in 3D printing applications. The material exhibits a lower crystallization rate than PEEK, which allows for better fusion between printed layers. This characteristic is crucial for producing parts with enhanced z-axis strength and isotropy, addressing one of the common challenges in 3D printing high-performance polymers.
PEKK also offers advantages in terms of processing temperature. While it maintains high-temperature resistance in its final form, PEKK can be processed at slightly lower temperatures than PEEK. This property can lead to reduced energy consumption during printing and potentially extend the lifespan of printing equipment. The processing window for PEKK is also wider, providing more flexibility in printing parameters and potentially improving print success rates.
PEKK's unique properties make it particularly suitable for aerospace, automotive, and industrial applications where high performance under extreme conditions is required.
The Science Behind High-Temperature Filaments
In the realm of high-temperature 3D printing, understanding glass transition temperature (Tg) is important. The Tg represents the point at which a polymer transitions from a rigid, glassy state to a more flexible, rubbery state.[1] For high-temperature filaments, a higher Tg is essential as it determines the material's ability to maintain its structural integrity under heat stress. High-temperature 3D printing is typically defined by the use of materials with glass transition temperatures above 120°C.
The following table compares the Tg values of standard and high-temperature filaments:
Filament Type | Glass Transition Temperature (°C) | Molecular Structure Stability |
PLA | 60 | Low |
ABS | 105 | Moderate |
PETG | 80 | Moderate |
ASA | 105 | High |
PEEK | 143 | Very High |
ULTEM | 217 | Very High |
PEKK | 160 | Very High |
The molecular structure of a polymer plays a pivotal role in its heat resistance. High-temperature filaments like PEEK, ULTEM, and PEKK possess complex, rigid molecular structures with strong intermolecular bonds. These structures resist deformation at elevated temperatures, maintaining their mechanical properties well above the point where standard filaments would fail. The stability of their molecular structure directly correlates with their superior thermal performance, allowing them to withstand extreme conditions in demanding engineering applications.
In addition to glass transition temperature, a material’s heat deflection temperature (HDT) and Vicat softening point are also valuable indicators of its heat resistance:
- HDT measures the temperature at which a material deforms under load, giving insight into its performance in high-temperature, stress-loaded environments.
- Vicat Softening Point, on the other hand, is determined by the temperature at which a standard needle penetrates the material to a specific depth under controlled conditions. This test helps gauge when the material starts to soften rather than melt.
Hardware and Process Requirements for High-Temp Printing
The Intamsys FUNMAT HT is one of the more affordable high-temp 3D printers (credit: Intamsys)
High-temperature 3D printing demands specialized hardware capable of withstanding and precisely controlling elevated temperatures. The unique properties of high-temp filaments like PEEK, ULTEM, and PEKK necessitate robust equipment designed to handle their extreme melting points and processing requirements.
In 2024, the high-temperature FDM 3D printer market is expanding due to the demand for advanced materials like PEEK and ULTEM. Stratasys is a market leader with its Fortus series, offering industrial-grade printing with high heat tolerance for aerospace and automotive applications. Other hardware companies include AON3D with its M2+ printer, known for dual extrusion and large build volumes, and Roboze with its Argo series that excels in precision and repeatability for high-performance polymers. Elsewhere the INTAMSYS Funmat range has affordable models like the HT and Pro series, while 3DGence offers robust solutions with its Industry line. MiniFactory's Ultra series also supports high-temp 3D printing materials.
Key Components
All-metal hot ends are a crucial component in high-temp 3D printer extruders. Unlike standard hot ends that may contain PTFE liners, all-metal variants can withstand the high temperatures required to melt engineering-grade thermoplastics without degrading. These hot ends typically feature heat breaks made of titanium or other high-performance alloys to maintain a sharp thermal transition zone, preventing heat creep and ensuring consistent filament flow.
Precisely controlled heated build chambers are essential for maintaining optimal printing conditions throughout the build process. These enclosed environments help prevent rapid cooling and warping of printed parts, which is particularly critical for materials with high crystallization rates. A controlled chamber temperature also aids in reducing internal stresses in the printed parts, resulting in improved mechanical properties and dimensional accuracy.
High-temperature bed materials are another key aspect of high-temp 3D printing. Standard build surfaces like glass or PEI sheets are inadequate for the extreme temperatures required. Instead, materials such as polyimide films or ceramic-coated plates are used to provide a stable, high-temperature resistant surface that ensures proper adhesion of the first layer while withstanding the heat from both the bed and the heated chamber.
Temperature Control
Temperature management and control — as opposed to the mere generation of very high temperatures — is the cornerstone of successful high-temperature 3D printing. The precise control of thermal conditions throughout the printing process directly impacts the quality, strength, and dimensional accuracy of the final part. High-performance polymers like PEEK, ULTEM, and PEKK require exacting temperature control due to their high melting points and sensitivity to thermal gradients.
The critical role of temperature management in high-temp printing stems from several factors:
Material Behavior: High-temp filaments have specific temperature ranges where they exhibit optimal flow characteristics. Deviations from these ranges can lead to poor layer adhesion, warping, or even material degradation.
Crystallization Kinetics: Many high-temp polymers are semi-crystalline, and their crystallization behavior is highly temperature-dependent. Proper thermal management ensures the desired crystalline structure, which directly affects mechanical properties.
Thermal Stress: Rapid temperature changes can induce thermal stresses in printed parts, leading to warping, delamination, or internal defects. Controlled cooling rates are essential for minimizing these issues.
Dimensional Accuracy: Consistent temperature control helps maintain dimensional stability throughout the print, crucial for producing parts with tight tolerances.
Techniques for maintaining consistent temperatures throughout the print process include:
Multi-Zone Heating: Implementing separate temperature controls for the hot end, build plate, and chamber allows for precise thermal management at each stage of the printing process.
Thermal Insulation: Proper insulation of the build chamber minimizes heat loss and helps maintain a stable thermal environment.
Gradual Cooling: Implementing a controlled cool-down phase after printing helps reduce thermal stresses and improve part quality.
Real-Time Temperature Monitoring: Using high-precision thermocouples or infrared sensors to continuously monitor temperatures allows for immediate adjustments when deviations occur.
Adaptive Temperature Control: Advanced systems can adjust temperatures based on the geometry of the part being printed, compensating for heat accumulation in different areas.
Post-Processing to Improve Heat Resistance
Post-processing is a critical step in high-temperature 3D printing that can significantly enhance the mechanical properties, surface finish, and overall performance of printed parts. For high-temp applications of any 3D printed thermoplastic, specialized post-processing techniques are essential to unlock their full potential.
Annealing is a particularly effective method for enhancing the mechanical properties of high-temp 3D printed parts. The annealing process involves heating the part to a temperature below its melting point but above its glass transition temperature, holding it at this temperature for a specified time, and then cooling it slowly.
Annealing offers several benefits:
Improved Crystallinity: The controlled heating and cooling cycle allows polymer chains to rearrange, increasing crystallinity and enhancing strength and stiffness.[4]
Stress Relief: Annealing helps relieve internal stresses built up during the printing process, reducing the risk of warping or deformation over time.
Enhanced Layer Adhesion: The heat treatment can improve bonding between layers, leading to better isotropy in mechanical properties.
Increased Temperature Resistance: Properly annealed parts often exhibit higher heat deflection temperatures.
Recommended reading: The Ultimate Guide to 3D Printing Post-Processing Techniques
Temperature Resistance With Other 3D Printing Processes
Formlabs high-temp resin used to make prototype OXO coffee maker components (credit: Formlabs)
When it comes to printing high-temperature parts, several other 3D plastic 3D printing technologies besides FDM can be used. Resin 3D printing (SLA and DLP) can achieve highly detailed prints, but heat-resistant resins like High Temp Resin from Formlabs are required for thermal stability, capable of withstanding temperatures up to 238°C. However, resin prints tend to be brittle compared to other methods.
Powder processes like Selective Laser Sintering (SLS) can also be used for certain high-temperature applications, particularly with materials like Nylon 12 or Nylon 11, which can handle temperatures above 180°C. SLS parts are durable and isotropic, making them ideal for functional prototypes and end-use parts in automotive and aerospace industries. Multi Jet Fusion (MJF), developed by HP, is another option for high-temperature nylon printing. MJF offers superior surface finish and consistent mechanical properties, making it well-suited for demanding applications requiring thermal stability.
The most heat-resistant 3D printed metals include Inconel and tungsten, which can withstand temperatures above 1,000°C, making them ideal for aerospace and energy applications. For ceramics, silicon carbide and alumina offer exceptional thermal stability, withstanding over 1,500°C, making them crucial for high-performance industrial and engineering applications.
Conclusion
High-temperature 3D printer filaments have revolutionized the landscape of advanced manufacturing, offering engineers unprecedented capabilities in producing complex, high-performance parts. These materials, including PEEK, ULTEM, and PEKK, provide exceptional thermal resistance, mechanical strength, and chemical inertness, enabling their use in the most demanding applications across aerospace, automotive, and medical industries.
As additive manufacturing technology continues to advance, high-temp filaments are poised to play an increasingly crucial role in the production of critical components. From lightweight aerospace parts to patient-specific medical implants, these materials are pushing the boundaries of what's possible in engineering and design.
Frequently Asked Questions
Q: What are the main differences between PEEK and ULTEM in terms of performance?
A: PEEK generally offers higher mechanical strength and chemical resistance, while ULTEM has better flame-retardant properties and is often more cost-effective. PEEK has a slightly higher temperature resistance, but ULTEM is easier to print with due to its lower processing temperature.
Q: How do high-temp filaments compare to metal 3D printing for aerospace applications?
A: High-temp filaments offer significant weight savings and corrosion resistance compared to metals. While they may not match the strength of some metal alloys, they excel in producing complex geometries and can often be used for non-structural or semi-structural components, reducing overall weight and cost.
Q: What are the main challenges in printing with high-temp filaments?
A: The primary challenges include the need for specialized high-temperature printers, precise temperature control throughout the printing process, potential warping or delamination due to high thermal stresses, and the necessity for post-processing to achieve optimal mechanical properties.
Q: Can high-temp filaments be used for end-use parts in medical devices?
A: Yes, certain high-temp filaments like PEEK are biocompatible and can be used for end-use medical devices. They are particularly suitable for implants, surgical instruments, and custom prosthetics due to their strength, chemical resistance, and ability to be sterilized.
Q: How does the cost of high-temp 3D printing compare to traditional manufacturing methods?
A: While the material and equipment costs for high-temp 3D printing are higher than traditional methods, it can be more cost-effective for low to medium production runs, especially for complex parts. The ability to iterate designs quickly and produce custom parts without tooling can significantly reduce overall development costs and time-to-market.
References
[1] Kalogeras IM, Hagg Lobland HE. The nature of the glassy state: structure and glass transitions. Journal of Materials Education. 2012 Aug 1;34(3):69.
[2] Reddy KU, Verma PC, Rathi A, Saravanan P. A comprehensive mechanical characterization of as-printed and saliva soaked 3D printed PEEK specimens for low-cost dental implant applications. Materials Today Communications. 2023 Aug 1;36:106438.
[3] Krzeminski J, Blicharz B, Skalski A, Wroblewski G, Jakubowska M, Sloma M. Photonic curing of silver paths on 3D printed polymer substrate. Circuit World. 2019 Jun 7;45(1):9-14.
[4] Pastorek M, Kovalcik A. Effects of thermal annealing as polymer processing step on poly (lactic acid). Materials and Manufacturing Processes. 2018 Nov 18;33(15):1674-80.
Table of Contents
Common Heat-Resistant FilamentsEntry-Level OptionsPEEKULTEMPEKKThe Science Behind High-Temperature FilamentsHardware and Process Requirements for High-Temp PrintingKey ComponentsTemperature ControlPost-Processing to Improve Heat ResistanceTemperature Resistance With Other 3D Printing ProcessesConclusionFrequently Asked QuestionsReferences