Unmanned Aerial Vehicles Fly Via Additive Manufacturing
A wing fuel tank for an Arcturus T-20 UAV made with EOS laser sintered plastic (PA 2201) by Northwest Rapid Manufacturing (part of the Northwest UAV Propulsion Systems family of companies).
Photo courtesy of Northwest Rapid Manufacturing
Curious how expensive this process is. You mention aerospace, medical and dental, where high costs can presumably be absorbed. Given the durability and ease of assembly (by aggregating more subassemblies into one piece), DLS seems like it should have huge uptake in automotive, but I'm guessing at this point that it's just too expensive.
Direct Laser Sintering technologies as a means to help Unmanned Aerial Vehicles has definitely been on Design News' radar screen for a while and is a great application for this technology. We wrote about one of the first UAVs built with this method taking flight this summer--SULSA,the Southampton University Laser Sintered Aircraft, which was printed using the EOS EOSINT P730 nylon laser sintering machine.
The materials have been costly, but the earlier machines were, too. Added to that, because items are produced one at a time the per unit cost tends to be higher than unit costs of a high-volume manufacturing process. And that's exactly why this technique is still limited mostly to specialty and race cars, not volume automotive manufacturing.
I think some of the parts being produced by this method are replacing parts that were previously produced by forging with secondary machining. If this is the case, how do the final parts stand up without the grain structures of the forgings? Aren't sintered parts produced from powdered metals fused together with heat and pressure. It would therefore have no grain and be lacking the inherent strength generally associated with that feature. While that would be immaterial on dental crowns and similar items not subjected to torque requirements, engine parts may be problematic. This is akin to plywoood being replaced by particle board. If that is not the case, I wish someone would explain why or why not.
From what I've read, metal parts made by direct laser sintering are typically not fully dense. They can be infiltrated with a copper alloy to help fill some of the porosity, or treated by hot isostatic pressing (HIP'ing) to increase the density. But I would not expect them to have the mechanical properties of castings or forgings. I would expect them to be closer to powder metallurgy (P/M) parts in terms of properties. That being the case, I would be very careful about putting them in any application which sees significant amounts of tension, torsion, or bending. Does anyone have any numbers for mechanical properties of laser sintered metal powders?
Some sintered parts are then forged, which does produce an oriented grain structure, and in addition does increase the density. The ultimate success would be to create a means to do laser forging. I have no ideas on how to do that, but when such a macine is invented I will buy one and go into the laser forged parts business.
@William: There's no reason why you couldn't powder forge a laser sintered part - except that you'd have to build a forging die, which would tend to negate the whole "rapid" aspect of laser sintering. I agree that anyone who could figure out how to make a net shape part with wrought properties through a rapid process with no tooling would probably become a multi-gazillionaire overnight. This would be the Holy Grail of rapid manufacturing. However, like you, I don't have the slightest idea of how this could be done.
I think at some point in the not-too-distant future, laser sintering might become competitive with investment casting for small production volumes - basically, where the production volume is too small to justify the tooling investment. Of course, investment casting foundries could stay competitive by using the same technology to make rapid wax patterns - and, in fact, they already are. In terms of mechanical properties, I would expect an investment casting to be superior to a laser sintered part.
To be fair, investment casting technology has had about a five thousand year head start compared to laser sintering.
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