The companies have been testing the process gas between January 2020 and March 2021, investigating its effect on spatter formation and process stability during laser powder bed fusion of Ti64 lattice structures. Linde and 3D Medlab announced their collaboration in July of last year, outlining their intention to understand how atmospheric conditions in additive manufacturing processes impact on the quality of printed medical devices.
Nearly a year on, the companies have found that spatter emission was significantly reduced when working with argon-helium mixtures compared to argon alone. With the help of optical tomography pictures, the companies have confirmed a 35% decrease in spatter emissions which helps to reduce the risk of defective parts and improve the overall surface quality. Spatter is when molten metal particles caused by the laser splash against adjacent parts being printed. The occurrence of spatter inside the build environment can result in less fine quality part threads and when using argon alone during the testing, Linde and 3D Medlab found there was a significant amount of spatter occurring, while also believing the level of porosity could be improved upon.
Having complete more than a year’s worth of testing, the companies believe their research could have a big impact in the medical sector.
“The ability to print reliably repeatable products is key to improving product qualification, which is crucial for the medical industry,” commented Sophie Dubiez-Le Goff, Expert Powder Metallurgy for Additive Manufacturing, Linde. “Additionally, from a commercial perspective, printing time is the greatest single cost element in additive manufacturing, but this can be speeded up for thin parts by using just the right atmospheric gas mixture. Linde’s novel argon-helium mix has been developed to do just that and is a major step forward in the manufacture of titanium medical devices.”
“The results of our joint atmospheric gas study with Linde shows that the right balance of helium to argon in the process gas mixture – and ease of implementation – can make all the difference to both quality of output and productivity,” added Gael Volpi, Head of Additive Manufacturing at Marle Group, in which 3D Medlab is a division of.
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