3D Printing Metals
The ultimate keynote presentation at our current Additive Manufacturing Methods, held in Boston and co-hosted by SmarTech Evaluation, was given by Craig Sungail, the Vice President of World Analysis and Growth for World Superior Metals, which simply so occurred to be one of many occasion sponsors. Sungail was a part of our new 3D printing metals observe, and offered a really attention-grabbing discuss tantalum, “the opposite grey steel.”
“We’ve used different metals for years, like cobalt chrome and chrome steel, to make implants,” Sungail mentioned. “In 80% of the circumstances, for most individuals, it’s profitable. However 20% of the time, sufferers aren’t pleased with the outcomes.”
He went on to say that there’s a 10% revision price every year for surgical implants 3D printed out of those different supplies, for causes akin to an infection, fracture, and changing into dislodged. That’s why he mentioned that we should always all “think about tantalum in its place.”
“This steel has an extended historical past. We’ve been reviewing the literature for the previous 25 years. The authors fluctuate – physicians, universities, and many others. However there’s a broad, various group of individuals investigating this steel for medical gadgets.”
Sungail defined that these journals have decided that tantalum (Ta) shouldn’t be poisonous, which “can’t be mentioned for among the different metals on the market at the moment.” Moreover, the analysis exhibits that when utilizing tantalum for implants, the osseointegration (bone ingrowth) of the implant into present bone is fairly good, and maybe even higher than implants made with straight titanium or the Ti-64 alloy.
He pulled up a slide itemizing among the different advantages of utilizing tantalum to manufacture medical implants, together with the truth that it may improve native host protection mechanisms, and that it could even have some antibacterial properties.
Sungail provided a short historical past about tantalum, which is a transition steel/aspect. He defined how the fabric bought its identify, citing a slide about Greek mythology, which I had not been anticipating and was very attention-grabbing. Tantalus, the son of Zeus and a nymph, stole ambrosia and nectar from his father, and the punishment positively match the crime on this case – he was compelled to face in a pool of water that was tantalizingly near a fruit tree.
“The water would fade away, and the fruit was simply out of attain,” Sungail went on.
Then, in 1802, Swedish analytical chemist Anders Gustaf Ekeberg grew to become the primary individual to find tantalum when he efficiently separated it from nyobium. Ekeberg was tantalized for a very long time making an attempt to attain what many others had not, and as soon as he’d succeeded, he was given the consideration of naming each of the brand new parts.
“I’m assured that all of you has been touched by tantalum in a roundabout way,” Sungail mentioned. “It’s extremely conductive, with a excessive melting level, chemical and corrosion-resistant, dense, arduous, ductile, and biocompatible. Now we have to make use of biocompatible rigorously, however I’m utilizing it with the FDA definition – it’s been implanted in a roundabout way into the physique, and research concluded that the implant was biocompatible.”
Sungail mentioned that the most typical software for tantalum is within the capacitor sector, akin to when it’s used for cell telephones. It does have a 40-year historical past in medical gadgets, and it may be combined with supplies with a view to make tremendous parts, which can be utilized in generators for jet engines and vitality era.
He defined that the corporate is “really world,” with places within the US and Japan. GAM additionally has a controlling curiosity within the largest reserve of tantalum on the planet, which is in Australia. I’m skipping forward a little bit, however I assumed this was a great query – on the finish of the presentation, an attendee requested Sungail in regards to the potential environmental impression of mining tantalum. He defined that GAM does what he known as a “bag and tag” once they obtain ore from a battle nation.
“We guarantee the cash isn’t going to terrorists, we do it ethically. If it wasn’t mined ethically, we wouldn’t have gross sales,” he acknowledged.
Again to the place we had been, Sungail mentioned that two years in the past, the corporate was having a look on the varied AM markets, questioning which might be the very best to take part in with its tantalum. Identical to the above graph exhibits, GAM decided that its “worth proposition was finest in medical, and never automotive.”
“We realized we’d should bridge the chasm between early adopters and later innovators. We’d have to show the business about tantalum and that it may be printed,” he mentioned.
So the corporate set to work, utilizing 200W and 300W lasers to 3D print medical gadgets like spinal implants and baseplates out of its tantalum; these totally dense elements at the moment are in testing.
Sungail listed a number of explanation why tantalum is an effective materials to make use of in 3D printed medical gadgets – it resists blood clotting, so it may be used to manufacture stents, and its excessive floor friction, confirmed by way of a number of analysis research executed on animals, is sweet for implant stabilization.
Tantalum additionally has no drawback with corrosion, which has been reported as being a problem with different implant supplies. Sungail had a slide that confirmed an image of a non-tantalum 3D printed hip implant, which required revision post-surgery attributable to corrosion; researchers decided that it was triggered attributable to crevice (the oxygen impact) and galvanic (dissimilar metals). He defined that particles attributable to friction can result in much more points with implants, akin to irritation within the tissue across the joint, which may trigger extreme ache, and that cobalt chrome and Ti-64 implants may even result in poisonous results, like bone degradation, if absorbed into the physique.
“Tantalum doesn’t corrode in a standard physique,” Sungail mentioned. “Its solely attacker is hydrofloric acid, and threading also needs to not happen with tantalum.”
Wanting on the graph above, you possibly can see that the fabric’s printability comes right down to a number of components, of which bioinertness combines a number of; Sungail defined that “these are generic combos of assorted options for straightforward studying.”
“It’s considerably extra printable than another metals we use for medical gadgets,” he continued. “Tensile and elongation properties sadly aren’t nicely reported, so we turned to engineering handbooks for this informnation, and modulus will be tuned with this materials. There are 4 to 5 papers out now from researchers who printed tantalum and made it 70-80% porous, as a result of that is the candy spot for osseointegration. They seen that the elastic modulus precisely matched bone on this vary.”
Sungail mentioned that he’s been at many conferences the place individuals have concurred that tantalum is a superb materials, however don’t know tips on how to justify utilizing it because it’s costlier than Ti-64.
“That’s the flawed query,” he mentioned. “Ask the price to the affected person.”
Whereas searching for a well-documented surgical examine, GAM discovered an instance with a 3D printed transforaminal lumbar interbody fusion (TLIF) implant, which is proven within the slide under with the price profit instance evaluation.
“We regarded on the entire course of, shopping for the uncooked materials and printing and cleansing it and sterilizing it, packaging, surgical procedure, to the purpose the place the affected person walks out,” Sungail defined. “Tantalum’s contribution to this implant on the slide is .02%. I believe that’s almost negligible. Tantalum will enable the affected person to stroll out a lot faster and get better a lot faster.”
3D printing isn’t even the costliest a part of the entire course of – it’s the surgical procedure itself. If annual implant surgical procedure revisions will be prevented by even 5% from switching to tantalum, the medical business will save $300-500 million a 12 months.
One other instance Sungail shared was a 3D printed knee implant made out of tantalum. The surgical procedure happened in China again in 2017, and the affected person was truly in a position to arise two hours post-op…that’s a fairly spectacular feat.
Wrapping issues up, he pulled up a slide exhibiting GAM’s “present” tantalum merchandise for 3D printing. In its angular powder kind, the fabric works for chilly spray expertise and DED printing, whereas spherical powder can be utilized with laser AM applied sciences. He mentioned that the corporate can be engaged on tantalum tungsten, and is “at all times searching for companions,” particularly since GAM doesn’t have its personal 3D printing system but and depends on its partnerships to print tantalum for them. Nevertheless, Sungail mentioned they’re contemplating a 3D printer buy…maybe that is an announcement we’ll see within the close to future?
Keep tuned to 3DPrint.com as we proceed to convey you the information from AMS 2020.
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[Photos: Sarah Saunders]
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