Sandvik creates 3D printed diamond composite

May 23, 2019 By Leslie Langnau

It may not sparkle like jewelry diamonds. That only means it is better suited to industrial uses. Sandvik’s new process means that this super-hard material can be 3D printed in highly complex shapes and can potentially revolutionize the way industry uses the hardest natural material on the planet.

Diamonds are a key component in a range of wear resistant tools in industry, from mining and drilling to machining and also medical implants. Since 1953 it has been possible to produce synthetic diamond, but since it’s so hard and complicated to machine, it is almost impossible to form complex shapes.

Until now, the production of super hard diamond materials allowed for a few simple geometric configurations to be formed. By using additive manufacturing and a tailor-made, proprietary post-processing method, Sandvik has managed to 3D print diamond composites which can be formed into almost any shape.

The difference between Sandvik’s diamond and natural or synthetic diamond is that Sandvik’s is a composite material. Most of the material is diamond, but to make it printable and dense it needs to be cemented in a very hard matrix material, keeping the most important physical properties of pure diamond.

Due to Sandvik’s use of additive manufacturing, diamond components can be created application ready, in very complex shapes, without the need for further machining. This will open up the possibility of using it in applications that were previously considered impossible.

“Historically, 3D printing in diamond was something that none of us imagined was achievable,” explained Anders Ohlsson, Delivery Manager at Sandvik Additive Manufacturing. “Even now we are just starting to grasp the possibilities and applications that this breakthrough could have.

“On seeing its potential, we began to wonder what else would be possible from 3D-printing complex shapes in a material that is three times stiffer than steel, with heat conductivity higher than copper, the thermal expansion close to Invar – and with a density close to aluminum. These benefits make us believe that you will see this diamond composite in new advanced industrial applications ranging from wear parts to space programs, in just a few years from now.”

The 3D printing process
“The additive manufacturing process used is highly advanced,” explained Mikael Schuisky, Head of R&D and Operations at Sandvik Additive Manufacturing. “We are printing in a slurry consisting of diamond powder and polymer using stereolithography.

The step after the 3D-printing is however more demanding. This is where Sandvik has developed, a tailor-made, proprietary post processing method making it possible to achieve the exact properties of the super-hard diamond composite.

“This step was extremely complicated. After extensive R&D efforts and several trials we managed to take control over the process and made the first 3D printed diamond composite.”

“Rather than looking to actually develop completely new materials, today the big push within the industry involves the often-radical restructuring of existing materials,” said Annika Borgenstam, Professor at the Department of Materials Science and Engineering at Stockholm’s KTH Royal Institute of Technology.  “Using revolutionary new processes such as additive manufacturing will open up new ways of using the same types of materials that we have today, by building in the properties that we need.”

“Sandvik’s 3D printed diamond composite is a true innovation. It means that we can begin to use diamond in applications and shapes never conceived possible before,” said Susanne Norgren, Adjunct Professor in Applied Materials Science at Uppsala University. “Just imagine what it could do to industries, when it is possible to print anything, in any shape – in diamond.”

Sustainable with superior properties
The diamond powder in Sandvik’s process can be extracted from the polymer in the slurry after the printing, and then be recycled and reused in another print-job.

The diamond composite has been tested and found to have extremely high hardness, exceptional heat conductivity, while also possessing low density, very good thermal expansion and fantastic corrosion resistance.

“We now have the ability to create strong diamond composites in complex shapes through additive manufacturing, which fundamentally will change the way industries will use this material. As of now, the only limit to how this super-hard material can be shaped and used is the designer’s imagination,” Mikael Schuisky concluded.

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