Researchers develop a new method based on abrasion to produce 3D printing powders

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Researchers at the Indian Institute of Science (IISc) have developed a new method based on abrasion to produce metal powders for 3D printing.

The approach is designed to provide an alternative to atomization, the technique by which most metal powders are currently produced. In atomization, a jet of gas or water is used to break up a stream of molten metal into tiny droplets, which form powder particles when cooled.

Unfortunately, despite being the gold standard in the industry, atomization-based powder production can suffer from low material yield, can be uneconomical, and is not compatible only with a limited number of metals. The IISc approach aims to fill these gaps.

Priti Ranjan Panda, Ph.D. student at IISc’s Center for Product Design and Manufacturing, said: “We have an alternative, more economical and inherently scalable way to manufacture metal powders, and the quality of the final powders appears to be very competitive with the powders gas-atomized conventional ones.”

Steel 3D printing powder produced by surface grinding. Images via IISc.

Grinding of metals for the production of powder

In manufacturing, the waste material removed from metal grinding processes is called swarf. These metal shavings often appear as long, thin strips, but they can also include spherical powder particles.

According to the IISc team, it has long been thought that these spherical chip particles melt during the grinding process, making them perfect spheres in the first place. Thus, the researchers hypothesized that they could apply metal grinding, an abrasion-based process, to the production of 3D printing powders.

The study showed that melting due to high heat of oxidation does indeed cause the formation of powdered metal particles via an exothermic reaction on the surface of a metal. The researchers refined the milling approach and optimized it to produce large quantities of steel 3D printing powder, which they claim performs on par with their gas-atomized commercial counterparts. The grinding technique is also significantly more cost effective than gas atomization.

The Indian Institute of Science.  Photo via IISc.
The Indian Institute of Science. Photo via IISc.

The need for cost-effective metal powders

Koushik Viswanathan, lead author of the study, says that there has recently been great interest in adopting metal 3D printing due to the customization benefits and design freedom of the technology. However, the expensive nature of metal powders today has proven to be a hindrance for many companies, so there is still a need for cheaper and more accessible powders.

Harish Singh Dhami, co-author of the study, adds, “Reducing the cost of the AM process (via cost-effective powders) can expand the range of materials in situations such as the fabrication of biomedical implants, which could become less expensive and more accessible.

Additionally, the team believes their abrasion-based approach also has potential in other high-performance industrial applications, including aerospace engine parts.

Further details of the study can be found in the article titled “Producing Powders for Metal Additive Manufacturing Applications Using Surface Grinding”.

The powder 3D printing materials industry is busier than ever. Just recently, Swedish materials company Gränges Powder Metallurgy launched its very first additive manufacturing powder. Developed as part of the company’s DISPAL family of materials, AM S220 (AlSi35) is a high performance aluminum alloy suitable for laser powder bed fusion. The material is characterized by its high stiffness, low thermal expansion, excellent wear behavior, good machinability and low density.

Elsewhere, Germany-based smart materials developer Infinite Flex recently launched what it claims is the world’s first pure copper powder for SLM 3D printing. Called INFINITE POWDER Cu 01, the material has already been successfully tested on a number of standard SLM 3D printers such as the EOS M290 and Trumpf TruPrint 1000, and is now commercially available.

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Featured image shows steel 3D printing powder produced using surface grinding. Image via IISc.

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