High-temperature polymers are all the rage right now in 3D printing, and for good reason. Materials like PEEK, PEKK, and ULTEM are reshaping the manufacturing space with their high strength-to-weight ratios, chemical resistance, and high operating temperatures. As a manufacturer of 3D printers designed for industrial applications, AON3D prepared a webinar to give you the low down on these high-temp materials.
Viv Campbell, Applications Expert, heads up the webinar. She begins by going over the current demand for HT materials. The aerospace industry is one of their biggest customers because weight reduction is so critical when flying metal planes through the air. They print parts for cabin interiors including housing, brackets, and mounts. The minimal outgassing of such materials is especially important for parts that go to space. Automotive manufacturers are also adopting HT materials for tooling and manufacturing aids; lighter jigs and fixtures translate to a safer and more productive factory. Biomedical industries are fond of the materials because they can withstand autoclaving and sterilization by ethylene oxide, steam, and gamma rays. They’re also strong enough to support specific weight profiles and are safe for skin contact. Finally, education institutes are researching the properties and uses of HT 3D printing materials. They are, after all, the strongest 3D printable polymers on the market.
Dr. Abraham Avalos, Head Scientist at AON3D, takes over to provide a brief lesson on the chemistry of 3D printing amorphous and semicrystalline polymers as well as glass transition temperature ranges. It’s quite interesting for those that want to know how molecular chains relate to the quality of their prints.
Additionally, he discusses the properties of the big three HT polymers:
- PEEK – excellent mechanical strength, vacuum-compatible, resists thermal degradation and can operate at continuous temperatures of 250°C
- PEKK – similar mechanical properties to PEEK but more printable, biocompatible
- ULTEM 9085 (PEI) – the most popular form of PEI, low flammability, highly printable, chemically resistant, very rigid, good dimensional stability
Campbell then returns to touch on print success with HT materials, which are more hygroscopic than most 3D printing materials. This means they absorb moisture from the environment, and moisture can cause polymers to crystallize sooner and inhibit layer bonding. HT materials are extremely hygroscopic and need to be actively dried in a convection oven before use. Process controls are also more critical for HT materials, and that includes more than just nozzle, bed, and chamber temperatures. Convection across the part, the melt zone, micro-retractions, and the first layer all have to be precisely monitored to achieve high-quality prints.
Z-axis strength is better on HT polymers but only if good layer bonding is achieved. Layer bonding is dependent on layer height and width, nozzle and chamber temperature, and print speed so process controls are just as important here. To optimize layer bonding, different heat settings for amorphous and semicrystalline polymers are available through print profiles on the AON-M2, and annealing can improve the crystalline state of PEEK and PEKK parts.
Finally, the presenters provide some features to look for when choosing a 3D printer that can handle HT materials:
- The most obvious requirement is a hotend that can sustain high temperatures and has liquid cooling.
- A heated build plate and an enclosed, heated chamber are also necessary.
- PEEK, PEKK, and ULTEM resist adhesives so being able to print large parts as a single piece is important.
- The software should be powerful, accessible, and flexible.
- And, ideally, the printer should operate on an open-materials platform so that users can choose their own suppliers.
Of course, the AON-M2 has dual, independent, liquid-cooled hotends that can reach temperatures over 500°C. Its build plate can reach 200°C. The enclosed build chamber can reach 120°C and is equipped with controllable forced convection to create isothermal conditions. It has a large 18”x18”x25” build volume and comes with a license to Simplify3D slicing software that’s loaded with print profiles for all HT and standard materials. AON3D wants to empower its customers so all of their systems are open to any material brand.
Indeed, they certainly check all the boxes. That makes sense because AON3D was founded by materials engineers. They understand how process parameters and polymer chemistry impact part properties so it follows that they can design a solid 3D printer for HT materials.