3D printed diamond composite

Sandvik reveals 3D-printed diamond composite

Image credit: Sandvik Additive Manufacturing

The Swedish engineering company has marked a world first by creating the first 3D-printed diamond composite, which has wide-ranging industrial uses.

Diamond may be the most lusted-after and enduring stone on Earth but it is also a factory’s best friend. It is extremely useful in industry, being 15 times harder than any other natural material. Diamond coatings, blades, and tips are found on wear-resistant tools across a range of fields, including mining, surgery, and drilling.

The hardness of diamond is a double-edged sword; while useful for cutting and shaping other materials, it is incredibly difficult to reshape itself. Even the development of synthetic diamond in the 1950s did not allow for complex shapes to be formed, as synthetic diamonds can only be formed into a handful of simple geometric shapes.

Now, Stockholm-based Sandvik has become the first in the world to 3D-print diamond powder, opening up countless possibilities for new super-hard industrial tools.

Unlike a natural or synthetic diamond, Sandvik’s diamond creations are composites: the diamond is ‘cemented’ in a very small amount of hard polymer matrix material such that it can printed while retaining its most valuable physical properties. The diamond composite is printed via a method called stereolithography: each layer of diamond and polymer 'slurry' is illuminated and set using a very precise ultraviolet light before the next layer is added and treated.

Once printed, the custom diamonds undergo a complicated secret post-processing method which reproduces diamond’s desirable properties. After printing, diamond powder can be extracted from the polymer and reused to create another object, making the process highly sustainable.

The diamond composite may not shimmer like the Koh-i-Noor, but it can be printed in essentially any shape no matter the complexity and with no need for further machining.

Speaking at a press event in Sandviken, Sweden, a Sandvik spokesperson commented: “[This is] the first time that anyone has printed this type of hard material”. The 3D-printed composite has been revealed publicly for the first time at the RAPID + TCT show in Detroit.

“Historically, 3D printing in diamond was something that none of us imagined was achievable,” said 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 the diamond composite in new advanced industrial applications ranging from wear parts to space programmes in just a few years from now.”

The diamond composite was tested, and was found to have extremely high hardness, exceptional heat conductivity, low density, very good thermal expansion, and “fantastic” corrosion resistance.

A custom diamond composite tool is unlikely to come cheap, but Sandvik engineers are confident that the unique objects will be worth the initial investment. A company representative told reporters that: “Diamond itself is expensive, and now you’re creating a shape that hopefully will give you value in your process after.”

According to Professor Annika Borgenstam, a materials expert at Stockholm’s KTH Royal Institute of Technology, processes like 3D printing will be increasingly used to find new ways of using known materials: “Rather than looking to actually develop completely new materials, today the big push within the industry involves the often-radical restructuring of existing materials.”

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