Interview: ETH Zurich start

Jul 11, 2023

"We have the ability to bring industrial scale silicone 3D printing to the mass market."

by Sam Davies

25 September 2018

09:00

Spectroplast AG

Soft robotic applications printed by Spectroplast.

An SLA 3D printing silicone service geared towards meeting the production needs of multiple vertical markets has been launched in Zurich, Switzerland.

Spectroplast AG has been spun out of ETH Zurich after five years of research and development in silicone resins, and within that timeline, between 18-24 months working on the hardware side. The company has been founded by a foursome with interdisciplinary experiences and expertise, from materials science PhDs to entrepreneurial prestige. But it is a group that feels it has the means to achieve industrial-scale silicone 3D printing, and in doing so, oblige many a client high quality products.

Powering this service is a VAT photopolymerisation process comparable to others on the market and patent-pending materials technologies, the intricate details of which remain secure behind the company's tight-lipped hierarchy. All CEO & co-founder, Manuel Schaffner would divulge is after an additive is added to a silicone resin, the print platform lowers itself into the resin tank up to the surface of the silicone, a wiper splits a thin film of silicone onto said platform for each layer, a light illuminates the areas that need solidifying, and with that process repeating, a usable silicone part is formed.

It's an alternative method of manufacturing with silicone. Traditionally, silicone products are produced with injection moulding, while companies like Fripp Design and Wacker are among the players in the additive manufacturing space to have developed technologies to support the 3D printing of the soft material. Fripp Designs’ Picsima method prints Room Temperature Vulcanising (RTV) silicone rubber by taking a base silicone oil, adding a cross linker to determine the softness, and then adding a catalyst through a 0.2mm aperture which polymerises the silicone sub surface. Wacker, on the other hand, uses a drop-on-demand process, the print depositing silicone voxels on a building platform to form a homogenous surface, before curing is activated with UV light.

Spectroplast AG

Models 3D printed in silicone by Spectroplast.

Spectroplast's method does away with the need for moulds and, according to Schaffner, works around some of the typical challenges of printing silicone. Being an SLA technology, almost by default, it significantly increases the print accuracy too.

"There are two main challenges when printing silicone," he told TCT. "The first one is that silicone has a really high viscosity, which means it behaves like a gel and doesn't really want to spread out, and spreading out is quite intrinsically important for making it accessible to 3D printing. The second challenge is that silicone usually solidifies at elevated temperatures. And both the viscosity, as well as the higher temperature solidification or cross linking required for silicone, are intrinsic challenges for 3D printing. With our patented technology, these limitations can be overcome, allowing us to make industrial standard silicone of high precision accessible to 3D printing without using moulds."

Another advantage of its silicone printing platform is the room for scalability. Currently, Spectroplast has a sole machine with building capabilities spanning 30 x 50 x 200 mm. The plan is not only to increase the number of SLA systems, but also the build area, initially to 300 x 450 x 200 mm, and at some point in the future, perhaps even greater than the largest SLA printer on the market. It feeds into the company's ambition of offering a genuine option for volume additive manufacturing of silicone products, and it is expected by the end of the year, Spectroplast will be a step closer to realising that vision.

Meanwhile, the company also has a prosperous approach to materials, its SLA printer able to support the silicone materials of all Shore hardness between Shore A 00-30 and Shore A 80, meaning parts as soft as gel shoe insoles can be printed, as can parts as tough as tire tread and shoe heels. Working side by side with its customers, Spectroplast aims to garner a comprehensive understanding of what they need and then customise a silicone material based on those requirements. It's been this way since the beginning.

Spectroplast AG

"We started off talking to many industries, and the goal is always to expand the range of materials accessible to 3D printing," Schaffner said. "And we realised that the soft elastomeric side is lacking right now, and that is when we started on this."

Those markets include soft robotics and aerospace, where flexibility and the ability to print lattice structures offer great advantages, or in the sportswear, footwear and baby care sectors, where silicone's softness can be of use. Other applications are expected to be seen in wearables, children's toys, and in the entertainment sector. The silicone market is expected to total more than $18Bn within the next five or so years. "Your imagination is where it ends," Schaffner exclaimed. Here in reality, where this venture is to end up having its largest impact looks likely to be in healthcare, which accounts for more than an eighteenth of those billions.

The company has earned ISO 10993-5 and ISO 10993-10 certifications which confirms its materials boast safe toxicity and no skin irritation, respectively. Thus, it paves the way for the service to be utilised by medical professionals far and wide, silicone a material that has for decades been used to manufacture hearing aids, implants, catheters, seals and gaskets, and feeding tubes, among other things. Then there's the customisation aptitude of 3D printing technologies to take into account.

"The entire healthcare industry is at the turning point where mass customisation, customised healthcare and pharmaceuticals, are just starting to take off," Schaffner noted. "We think that we can provide a solution to some extent, at least to soft implants and medical applications. So, really, the long-term strategy is medical."

Spectroplast AG

It's not hard to understand when you consider the ability, for example, to use SLA/ DLP technology to manufacture over 1,000,000 hearing aids a year like Sonova is doing with EnvisionTEC machines, or produce surgical guides on-demand with similar technology, like axial 3D. Spectroplast's unique selling point, of course, is the potential to achieve similar feats with a different group of materials. And that's the motivation for a company that has chosen now to come to market, a time when 3D printing silicone is still nascent, and mass customisation output in the service prover's target market is on the up.

"We have the ability to bring industrial scale silicone 3D printing to the mass market, and in a way that blends the characteristics of nature with our revolutionary additive manufacturing process," Schaffner articulates. "Today, additive manufacturing is mainly known as a technology to materialise rigid objects made out of metals, ceramics, and plastics, but when you look at what materials nature is actually employing, we realised that nature embosoms basically the entire cosmos of soft materials that transform, morph, and self-heal. Here are compliant materials that adapt, interact and conform to the environment, and such soft materials exhibit a number of unique characteristics that cannot be, or so far have not been, accessible to 3D printing.

"We believe 3D printing has the potential to shift focus from rapid prototyping to mass customisation of functional parts coming out straight off the printer, and with the world's first SLA silicone 3D printing technology we can expand the range of 3D printing materials from rigid and stiff materials to stretchable elastomeric materials, such as silicone."

by Sam Davies

25 September 2018

09:00

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