Thread by @Chethan_Dash

#Breaking #3Dprinting #Thread

@iiscbangalore researchers, addressing challenges of present techniques of obtaining metal powder, a major source for #3Dprinting has identified an alternative, low-cost technique to produce the same. To be useful across sectors. 1/n

Pointing out #3Dprinting creates objects by addition of material, layer by layer, @iiscbangalore said metal powders are predominantly produced using a technique called atomisation, in which a molten metal stream is broken up into fine droplets using air or water jets. 2/n

“However, despite its widespread use, atomisation returns poor yield, is expensive & inflexible in types of materials it can handle. A team led by Koushik Viswanathan, asst prof, dept of mechanical engg (DME), has identified a technique that side-steps these problems… 3/n

…This has interesting implications for AM processes in general, including areas such as the manufacture of biomedical implants,” @iiscbangalore said. 4/n

In the metal grinding industry, the material removed – called swarf – is often discarded as a waste product, IISc said, adding that this is commonly stringy in shape, like metal chips, but it often also throws up perfectly spherical particles. 5/n

Scientists have long theorised that these bodies go through a melting process to take up the spherical shape, thus posing some interesting questions like whether heat from the grinding causes the melting or Is there melting at all?... 6/n

…Now, Viswanathan’s team has shown that these powdery metal bodies form as a result of melting due to high heat from oxidation, an exothermic reaction, at the surface layer. 7/n

@iiscbangalore said they then refined this process to produce large quantities of spherical powders, which are collected & processed further to be used as stock material in #3Dprinting... 8/n

...Their study shows that these particles perform just as well as commercial gas atomised powders in the context of metal. 9/n

Priti Ranjan Panda, a PhD student at IISc’s CPDM & one of the authors, said: “We have an alternative, more economical, inherently scalable route for making metal powders. Quality of final powders appears to be very competitive compared with conventional atomised powders.” 10/n

Elaborating on the applications of their findings, Viswanathan said there has been significant recent interest in adopting metal AM because by nature, it enables significant customisation and allows design freedom. 11/n

“However, the large cost of stock metal powders has been the stumbling block. We hope that our work will open new doors to making cheaper and more accessible metal powders,” he said. 12/n

Reducing the cost of the AM process can widen the range of materials in situations such as manufacturing of biomedical implants, which could become cheaper and more accessible, Harish Singh Dhami, a PhD student at DME and co-author of the study said. 13/n

He added that making metal powder using abrasion also has potential in other high-performance applications such as in aircraft engines, where a high degree of specificity and sophistication are required. 14/n

Also, metal powders produced at an atomisation facility require transport for casting and recycling, thus setting up a big supply chain. 15/n

“This works for abundant metals like aluminium, but for strategic materials such as tantalum and lithium, where extraction alone is a complex process, it would be favourable to have a scalable process for producing metal powders… 16/n

…Then, in principle, the entire supply chain can be housed within a single facility – a possibility that their technique could offer,” Vishwanath added. n/n