3D printing a diamond composite

Sandvik Additive Manufacturing's super-hard material can be 3D printed in highly complex shapes, changing the way industry uses the hardest natural material on the planet.

Sandvik Additive Manufacturing has created the first ever 3D printed diamond composite and even if this diamond does not sparkle, it’s shines for a wide range of industrial uses.

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

Today, production of super hard diamond materials only has allowed for a few simple geometric configurations to be formed. By using additive manufacturing (AM) 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.

Enormous opportunities

With Sandvik’s use of AM, diamond components can now be created application ready, in very complex shapes, without the need for further machining. This opens 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 aluminium. 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 a method called stereolithography, where complex parts are produced, layer by layer, using ultraviolet light.”

The step after the 3D-printing is however even 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. However, after extensive R&D efforts and several trials we managed to take control over the process and made the first 3D printed diamond composite. It was incredible to see what we can achieve when we combine Sandvik’s leading expertise in materials technology with our strong capabilities in additive manufacturing and post processing,” Schuisky comments. “We have some of the world’s leading experts in both materials and additive manufacturing, which in a case like this can benefit many industries around the globe making it possible to use diamond in applications and shapes never conceived possible before.”

“Rather than looking to actually develop completely new materials, today the big push within the industry involves the often-radical restructuring of existing materials,” notes 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 completely new ways of using the same types of materials that we have today, by building in the properties that we need.”