Materials

Sinterit’s SLS 3D printing technology opens new applications for TPUs 

According to Polish 3D printer manufacturer Sinterit, recent advances in both additive manufacturing materials and systems, have increasingly led to their broad adoption within the textile sector. 

The company’s Lisa PRO system for instance, is compatible with a wider array of printing materials than many other desktop Selective Laser Sintering (SLS) machines. What’s more, by leveraging thermoplastic polyurethane (TPU) powders like Sinterit’s Flexa Grey material, it’s possible to fabricate flexible parts that can be used within the medical, textile, and fashion industries. 

Speaking to 3D Printing Industry, Max Polesello, CEO of Sinterit, waxed lyrical about the manufacturing potential of the firm’s proprietary materials. “Our TPU powders offer numerous benefits over traditional manufacturing materials such as polyamides (PA),” said Polesello. “By managing to be both strong and malleable at the same time, TPU can be utilized within a wide variety of industries, ranging from the healthcare sector to textiles.”

Sinterit's Lisa PRO is compatible with TPUs as well as PA 3D printing materials, opening a range of new applications to users. Image via Sinterit.
Sinterit’s Lisa PRO is compatible with TPUs as well as PA 3D printing materials, potentially opening a range of new applications to users. Image via Sinterit.

The flexibility benefits of adopting TPU 

Additive manufacturing is widely used for producing hard or rigid components that are not meant to provide any flex or give whatsoever. Powders such as Sinterit’s Flexa Soft on the other hand, reportedly provide an “exceptional” softness, which allows for the creation of more flexible parts.

The material’s adjustable hardness also enables the production of components with a high degree of elasticity, lending itself to prototyping and design applications, and parts such as shock protectors and absorbers. What’s more, the Flex Grey’s pliability doesn’t come at the expense of durability either, and Sinterit’s own testing benchmarks have shown that it had a tensile strength of 3.7 MPa, and an elongation at break of 137 percent. 

Konrad Glowacki, Co-founder of Sinterit, said at the product’s launch, that the powder’s potential lay in its combination with the firm’s LISA range of 3D printers. 

“Our clients are very keen on experimenting with new powders and continually asking us to develop new ones, which will broaden the manufacturing possibilities of both Sinterit LISA printers,” said Glowacki. “We are very open to those inquiries because we are aware that the full capabilities of SLS rapid prototyping have not been used yet.”

Sinterit's Flexa Grey 3D printing materials are soft and flexible, allowing them to be used within the medical and textile industries. Photo via Sinterit.
Sinterit’s Flexa Grey 3D printing materials are soft and flexible, allowing them to be used within the medical and textile industries. Photo via Sinterit.

3D printing in the fashion industry

The creative freedoms afforded by flexible resins in additive manufacturing has seen a variety of fabricated fashion lines being developed over the last few years. 3D printer manufacturer Stratasys, for instance, has created its own novel direct-to-textile PolyJet printing Technology, which allows digital designs to be printed straight onto materials. 

Stratasys first unveiled its ability to 3D print directly onto fabric at New York Fashion Week 2019. The collaboration with esteemed fashion designers threeASFOUR and Travis Fitch saw pieces from the ‘Chro-Morpho’ collection showcased by models at the runway show. Although 3D printing had previously been used to create additional costume elements, the overall project leveraged direct-printing in a way that had rarely been seen before. 

More recently, the company worked with fashion designers Ganit Goldstein and Julia Koerner to produce outfits with nature-inspired geometries. Each line was based on 3D body scans of the designated wearer, allowing for garments to be personalized in a novel way. The collaborations are part of the broader Re-FREAM project, which has brought together artists, designers, engineers, and scientists to explore the use of 3D printing within fashion.

A number of celebrities also wore 3D printed dresses at the 2019 Met Gala. American fashion designer Zac Posen partnered with GE Additive and Protolabs to bring a range of additive fashion items to the party. Posen’s “glass slipper” dress, which was worn at the show, took Protolabs over 200 hours to complete, including its 3D printing and finishing by sanding and clear coating.

In addition to fashion lines in the textile industry, the flexibility of TPUs has also been deployed within other areas of the clothing sector recently, as well as the production of devices for surgical preparation. 

The increasingly wide applications of TPU

Since Sinterit debuted its Flexa Grey TPU at Formnext 2018, the material has gone on to find a number of applications in the textile and medical industries. Medical researchers, in particular, have increasingly utilized 3D printing to fabricate replicas of human anatomy for surgical preparation purposes. If they were to print such models using conventional PA, the plastic would be too difficult to cut through with a scalpel. 

TPU, meanwhile, is an ideal alternative to PA, because it can easily take the model’s desired shape under load or pressure while retaining its geometry when unloaded. The fashion world has also recognized the potential of TPU polymers in recent years, with their softness and flexibility allowing them to easily adjust to the wearer’s body. 

Sinterit’s LISA systems are optimized for 3D printing fabrics, as they feature the firm’s patented SLS technology, which enables the creation of both knitted and weaving-inspired materials. Leveraging the LISA, it’s, therefore, possible to produce a number of structural fibers such as high-quality decorative items, upholstery for use within furniture or automotive applications, or even interior design items. 

For instance, one group of students has used Sinterit’s 3D printing technology to produce part of scenography for a play. Mingjing Lin and Tsai-Chun Huang, Ph.D. candidates in Fashion and Textile research at the Royal College of Art  London, decided to 3D print the pleating on a costume for the Beijing Opera. 

Leveraging additive manufacturing and TPU rather than silk or cotton, the duo was able to create the costumes in dramatic geometries that would not be possible using traditional production methods. What’s more, the variety of properties featured by Sinterit’s range of materials, allowed the students to choose each one, depending on its wearer. 

As a result, the outfits were able to synchronize with the actor’s bodies’ while keeping the same shape and form of the traditional costume. “While Flexa Bright shows perfect strength characteristics, other materials, like Flexa Soft, can be used to design sensory fabrics and sportswear prototypes,” concluded Polesello. “But the number of possible applications is innumerable, and the designers still surprised us with their approach.”

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Featured image shows a range of components that were fabricated using a Sinterit Lisa PRO 3D printer. Image via Sinterit.