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Designing a 3D METAL printer

metalbot

Plastic
Joined
Apr 26, 2013
Location
Canet, France
Hi everyone!

I would like to discuss the pros/cons and engineering challenges one would face in order to create a 3D printer capable of printing in metal.


I am sure most people here have heard of 3D Printers/printing, perhaps some of you've had the opportunity to use them.

From what I have learned, the two limiting factors with 3D printing have always been a - strength of the printed parts and b - part resolution. Hopefully it is possible to solve both of these problems by designing printer that works through a process called 'laser sintering' (although a few other avenues are being pursued).

I would be more than happy to answer any questions to the best of my knowledge!

Best regards,

Jethro.
 
Heresy I say!
If something ever replaces machining in my lifetime, I will be very pissed off!
"Jethro" talking about cutting edge tech...what is wrong with THAT picture? :)
 
Marcus the Implant Mechanix man and I are hatching a plot to get a 3D metal printer through some elaborate public/private/research/clinical/orthopaedic/dental partnership I'm currently pondering how to concoct. Thanks for the link Rob as this is the sort of stuff we want to look at. Anyway, the unit Marcus has identified is about $650,000. I do not see how you get from that sort of price point to a low cost open source metal printer than can do anything all that useful. As I understand it there are some fundamentally expensive parts to 3D printing such as powerful lasers and hydrogen ovens. Even for plastic 3D printers, the low cost ones really aren't past the amusing hobby level compared to real machines.
By the way I really don't think 3D printing is going to replace anything, but it does allow you do do certain difficult shapes or custom shapes more easily. We're only looking at one because between his shop and my institution we have all the mills, lathes, Wire and sinker EDM, Waterjet, grinding and welding machines already.

Here's a less unconventional link to the jawbone story. http://spectrum.ieee.org/podcast/biomedical/bionics/bone-transplantation-without-rejection

R
 
From what I have learned, the two limiting factors with 3D printing have always been a - strength of the printed parts and b - part resolution. Hopefully it is possible to solve both of these problems by designing printer that works through a process called 'laser sintering' (although a few other avenues are being pursued).

That's quite the challenge for an Open Source project. Direct metal printing is rare: most of the cool models you see on Youtube are powdered metal with an epoxy binder, and the laser sinters a very fragile foam model that must be baked in a kiln, and then backfilled with a filler metal like bronze.

The Matsuura that Moriboy links is one of the rare Direct Laser Sintering machines (EOS is the other big player): it spreads a layer of very fine metal powder in a tray, and then a 400W YAG laser locally melts each particle. If you watch the Matsuura video, it's building up those layers, 20 micrometres at a time :eek: At the end of each pass, the machine pauses, the squeegee spreads another fine layer of powdered metal, and the process repeats. Many, many, many times...

You can see that the direct laser sintering has a coarse styrofoam surface finish from the process. The Matsuura is unique (?) in that it's also a 5 axis machining center, and every X number of passes, it goes back over the laser sintered part with a miniature endmill and cleans up the part.

Good luck! :D
 
There was actually on article on something like that from either MMSonline or The Fabricator, I read it a few weeks ago, but it was 6-9 months old.
 
I realize the OP was a spammer, but in any event:

How about a MIG head and changing wire size for the resolution desired vs speed.

There's another Youtube video of a process very similar to that: I'm not sure if you can call it 3D printing: a 5-axis head carries a wire feed, and the head essentially builds the workpiece out of weld bead. It's much, MUCH faster than Direct Metal Laser Sintering, but it has a very coarse resolution. The final product truly does look like it was built-up from weld bead :)

It's funny though, I think 3D Printing is going to be one of those "almost ready for production" technologies for another 50 years: I ran across an article in Scientific American from 30 years ago describing 3D Printing, and how it was "on the verge of a breakthrough production method." ;)
 
3D printing is going to need a paradigm shift in technology to compete in production, for any material.

The metal printers I have see use a bronze matrix to sinter the base metal. So if you want to make something from steel, it's only a fraction steel, and only a fraction as strong.
 
3D printing is going to need a paradigm shift in technology to compete in production, for any material.

The metal printers I have see use a bronze matrix to sinter the base metal. So if you want to make something from steel, it's only a fraction steel, and only a fraction as strong.
Nope. Not any more. DMLS technology has matured into a viable option for many different types of parts.

DMLS parts made from Inco 718 have proven to have better mechanical properties than 718 castings. GE bought Morris Technologies and they are ready to put DMLS printed parts into gas turbine engines.

Morris Technologies : News
 
Nope. Not any more. DMLS technology has matured into a viable option for many different types of parts.

GE bought Morris Technologies and they are ready to put DMLS printed parts into gas turbine engines.

That summarizes every press release I've seen over 30 years about 3D Printing: they are ready to put the process into production.

If you watch the Matsuura video that Moriboy posted, they also show the construction of a turbine blade. So does EOS, the inventors of the DLMS process. That's because it's one of the few common industrial products that might make sense on a 3D printer.

You can see that the direct laser sintering has a coarse styrofoam surface finish from the process. The Matsuura is unique (?) in that it's also a 5 axis machining center, and every X number of passes, it goes back over the laser sintered part with a miniature endmill and cleans up the part.

From the American Machinist article about GE buying Morris Technologies:

http://americanmachinist.com/shop-operations/ge-aviation-takes-additive-manufacturing
geaviationadditivemfg.gif
 
@ Rob F. I read the exact same article, it is fascinating. The biggest pro to this tech is that complexity costs nothing. It requires the same level of expertise to print a block of metal as it would to print a perfect jaw bone replacement (provided you have the cad data). With regard to that article, the titanium can be printed so that the section that touches live tissue or bone is porous and can interface with the body well. This is called titanium osseointegration.

Here is more information: The First 3D Printed Jaw Implant they print in 20-40um layers. We have a target of printing in 30um layers.

@ jdj, in all likelihood 3D Metal Printing will not replace every aspect of machining or milling. The simple fact is that the more complex the part the more desirable it is to use 3D printing. In some applications it has already replaced machining, specifically in high end aerospace.

@rcoope, I have personally seen a couple of open source hardware projects take things that originally cost a few thousand down to a few hundred. (reprap, diy-drones). You are spot on about the major cost being high powered lasers (hydrogen ovens I'm not too sure about). We are looking at modifying a YAG or Fiber laser engraver that has the ability to melt metal powders. The other main costs will be a gas (argon or nitrogen) tight frame and fabricating a high precision powder system that can spread powder layers of 30um.

This is in fact on of the main reasons I started this topic here, we need help with the precision engineering of the powder system, any pointers would be much appreciated.

@ lazlo - I am surprised by how many people do not even know what 3D Printing is, let alone that it is possible to print in metal. I think the reason is that current systems are only used and known in the world of high end manufacture.

I had never heard of the Matsuura Lumex before but I know that the two main players in the world of laser sintering are EOS (fiber lasers) and Arcam (electron beams). We are currently looking at using lower powered lasers for a longer given time on a smaller surface area and with thinner layers.

There are many variables that need to be considered when sintering, for those interested:

Time spent on a given area - Size of the spot - laser wattage - laser wavelength - powder granule size - layer thickness - material.

One benefit of laser sintering is that there are no burrs.

@ ewlsey - Bronze infusion is an inferior technology and ill suited to the hobbyist (due to the requirement of a furnace). You might be surprised to hear that EOS EOS - e-Manufacturing Solutions has reported in a case study that their sintered titanium parts have shown an increase in strength as compared to a forged equivalent part! These printed parts are fully dense and can be used in real world applications.

@Philabuster - exactly.

As for the allegations of SPAM, I have posted the first post in a few other forums as I am willing to discuss this subject in a few other forums. Also it makes no sense to word it differently as it is what it is :) . I am sorry if it has come across wrongly!

Regards!

Jethro.
 
I am surprised by how many people do not even know what 3D Printing is, let alone that it is possible to print in metal. I think the reason is that current systems are only used and known in the world of high end manufacture.

The EOS and Matsuura machines are used for prototyping and one-offs. According to the American Machinist articles (I linked above), they've never been used in production, for obvious reasons.
 
There's another Youtube video of a process very similar to that: I'm not sure if you can call it 3D printing: a 5-axis head carries a wire feed, and the head essentially builds the workpiece out of weld bead. It's much, MUCH faster than Direct Metal Laser Sintering, but it has a very coarse resolution. The final product truly does look like it was built-up from weld bead :)
That could replace the need for castings for small runs though? Print weldment version, and put it in the vmc for final machining to high tolerance. Assuming the weld isn't going to be full of inclusions etc.
 
Nope. Not any more. DMLS technology has matured into a viable option for many different types of parts.

DMLS parts made from Inco 718 have proven to have better mechanical properties than 718 castings. GE bought Morris Technologies and they are ready to put DMLS printed parts into gas turbine engines.

Morris Technologies : News


I always asked why they couldn't cast impellers and had to machine them from solid. Do you (or anyone) ACTUALLY mean to tell me that this new 3D METAL printing has surpassed a technology that has had MUCH MORE TIME to be finessed? Pardon my skepticism, but...
 
We have a couple of laser sintering machines where I work. They are used to make dental crowns. We use a cobalt chrome powder and cook the finished product in an oven with a nitrogen atmosphere at about 2200F. Liquid nitrogen is used to cool the laser and the process is done under vacuum. They are pretty cool to watch run; it makes tiny sparks each time the laser hits a spot and it happens pretty rapidly.
 
You people are high.

I remember the same buzz with powdered metal. "You can make metals parts any shape you want" they said.

There are some neat things that can be done with 3D printing. Production is not one. Some shops are making prototype patterns on 3D printers, but it is usually faster just to mill them. There is a company that can 3D print sand cores. That saves having to make a core box. Again, machining a core box is cheaper for more than a handful of parts.
 
There's another Youtube video of a process very similar to that: I'm not sure if you can call it 3D printing: a 5-axis head carries a wire feed, and the head essentially builds the workpiece out of weld bead. It's much, MUCH faster than Direct Metal Laser Sintering, but it has a very coarse resolution. The final product truly does look like it was built-up from weld bead :)

It's funny though, I think 3D Printing is going to be one of those "almost ready for production" technologies for another 50 years: I ran across an article in Scientific American from 30 years ago describing 3D Printing, and how it was "on the verge of a breakthrough production method." ;)

Do you have any links? I'm curious to see it in action.

Personally I'm far more confident in the future of 3D printing than some seem to be here, at least when it comes to plastics. I definitely believe that well within my lifetime each home will have a 3D printer and many things that would be manufactured in bulk and distributed will instead be printed at home as one-offs. Call me a dreamer, but even I was very close to building a 3D printer for casting patterns but decided I didn't have enough call for it.

Metals? Yeah maybe a lot further away yet, but once affordable plastics are refined I don't think metals will be that far behind.

Pete
 








 
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