3D Printed Turbine Blades for More Efficient Power Generation | The Cool Parts Show #35

[@glennsharkie4882]

When he says Turbans, does he mean Turbines?

[@lincolnengland5005]

Lol.....yes it's the silent 'e'!

[@lincolnengland5005]

I don't wish to rain on your parade but Siemens Energy printed AND tested an HP Turbine Blade years ago.....these appear to be LPT's. AM has a lot of promise but has a loooong way to go. I have no doubt it's the future but not anytime soon. Keep persevering folks!

[@coreydickman8639]

This video failed to mention that the EBM process pre-sinters the powder in each layer, such that internal channels (especially small diameter and complex paths) become very challenging, if not impossible, to remove the powder. Yes, laser processes are subject to more distortion and more design restrictions, but they also make it much easier to remove the powder from complex internal features. Laser processes also use Inconel 718 and 625, which in my experience are not prone to cracking. I could be wrong here since I don't have direct experience with EBM, so any feedback would be greatly appreciated.

[@sumankvdas]

Completely agree. The show host can blather go on and on about complex internal passages but he doesn't know what he is talking about. The passages will be extremely difficult if not impossible to make via EBM and even PBF. The demanded surface finish on those passages is less than 5 microns Ra. First you need to get the powder out of those tortuous passages which in some cases will take more than a few weeks to do so, if at all you are successful. One major OEM making turbine blades with PBF was scrapping 30% of their printed blades because they couldn't get the powder out of those passages reliably. Every one of those blades will need to be X-rayed to make sure there are no powder particles left behind inside those passages and the passages are squeaky clean and dimensionally correct. This will be an iterative process of clean, inspect, clean, inspect adding to cost astronomically. Next, as is apparent from the pictures of the blades shown, the surface finish is absolutely terrible, not even close to as-cast surface finish of similar parts made traditionally via investment casting. It looks like a sand casting rather than an investment casting. The surface finish on those internal passages will be at least as bad as that on the exterior surface, if not worse due to partially sintered powder particles stuck to the inner walls. All of those passages will need to be cleaned and polished with abrasive flow machining and chemical etching, further adding machining cost. Furthermore, due to the intense heat and thermal gradients experienced by the part during layerwise printing, with heat, cool, heat, cool for each layer from roughly 600 degrees C to 1500 degrees C, there will be significant distortions that will cause the part to deviate from the nominal geometry in the starting CAD model. It is extremely difficult to (a) non-linearly compensate the print instructions to account for the distortions that will occur as a result of both print resolution and heat related distortion and (b) compensate the print instructions to add sufficient metal stock to the nominal part to allow for the multiple machining processes to get the part to the design print dimensional tolerances and surface finish. Lastly, there will be the need to have a custom and complex heat treatment cycle to get the microstructure of the alloy to be comparable to cast Inconel 738 which has been well understood for decades. Finally, the part density, elevated temperatures mechanical properties (tensile, hardness, creep) etc at elevated temperatures will need to be qualified to match those of commercial cast parts. The process is akin to making a trillion welds, and is a long road...

[@AdditiveManufacturing]

Mike Kirka, who you saw in this episode, offers this response: “Yes, laser powder bed fusion processes are extensively used for the processing of Inconel 625 and Inconel 718. However, these are weldable alloys. The alloy used in this case, Inconel 738, is a high gamma prime superalloy that was designed for casting of blades and falls into the traditionally non-weldable category. Laser powder bed fusion processes have not demonstrated the ability to date to process non-weldable Ni-bae superalloys crack-free and in complex geometries. A difficulty of the EBM process is the removal of the lightly sintered powder from internal passages, but methodologies do exist for removing the powder. This is a factor that must be considered when designing components to be fabricated through EBM, similar to the way laser powder bed processes have more restrictions on overhangs than EBM. In the case of the blades seen in the video, they belong to stage two and are solid (non-cooled), so powder removal was not a factor. Overall, each of the AM processes is a tool in the tool box, with the right tool being chosen based on a combination of materials processing capability, economics, and attainment of component design/performance goals.”

[@coreydickman8639]

​@@AdditiveManufacturing Ahhh...thank you for the explanation on the material choice! I always enjoy learning about processes for which I don't have direct experience with. Totally agree that both processes are complimentary... EBM is likely a better candidate for larger / thick walled parts, but I can't imagine how you'd remove partially sintered powder in a complex internal cavity without some extraordinary process. Even un-sintered powder in laser processes is notoriously difficult to remove without careful design and post-process planning for complex internal cavities. A quick search of the current literature seems to indicate that this is still a major hurdle for EBM as blasting seems to only work for directly accessible geometry. A novel solution would be a huge win for both processes! In EBM, is there a way to omit even a tiny portion of the build from being partially sintered?

[@balajjamal2671]

Turbans?

[@phaniyanala9954]

Did any one notice ?, they both look like Sheldon and Amy from "big bang theory". I'm really enjoying this "the AM cool parts show".

[@cwmaguire]

Love the show, as always, even though I have nothing to do with manufacturing.

[@ericphantri96734]

For prototyping then 3 d can help in making some part beyond CNC capacity

[@bob.bobman]

Failed to mention results of test. Thank you for video though interesting.

[@britttullos8119]

“Ter-bin”?

[@joshtechjunction7041]

which tech is more promising when it comes to strength and performance of turbo machinery parts , LPBF /EBM or Binder jetting?

[@sumankvdas]

PBF and EBM are akin to casting and will give similar results in strength and performance, but in the context of specific alloy capability. Binder jetting is a modified version of powder metallurgy and will not come even close.

[@AdditiveManufacturing]

Here is a reply from Mike Kirka, Oak Ridge National Laboratory, who appeared in this episode: “Each technology is a tool in the toolbox. Which one to use depends on the material, the necessary feature resolution, the economics associated with the part application, and ultimately the size of the part. In this case, we leveraged EBM to develop the science necessary to process a non-weldable crack-prone superalloy that cannot be processed successfully in complex geometries free of cracks in laser powder bed fusion based on current machine technology.”

[@Aaron_b_c]

TurbIne. Not turban

[@hafizuddinmohdlowhim8426]

From this video, it doesn’t show the test result. So I don’t see that this 3D printer works.

[@austumaspapartis6722]

Waste of time and money. 3D printed metal parts are EXTREMELY difficult to balance. While this might be useful for a rapid prototyping, but not much beyond that. No serious engineer would choose to 3D print the steam engine blades. the vibrations would be horrible :)

[@beng6319]

Some metal 3d printers have post machining processes built into the machine. That can get the part to exact dimensions and weight. The best engineers are the ones that can figure out how to make something work out of a process previously deemed impossible.