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Aluminum (aluminium) printing

Posted by sid 
Re: Aluminum (aluminium) printing
October 15, 2013 07:15AM
I've been reading for a while your posts and other stuff on the web about laser sintering, I've got to tell you: this is something that I don't understand much, but, in my opinion, the only way to learn is to read and discuss about it. smiling smiley

In my opinion to sinter powders (aluminium in this case), maybe we should start to pre-heat a chamber on an Inert gas environment, yet there would be a problem, problem which is to make the chamber oxygen free, on which leakages could deal a real problem, maybe. While this is happening we also need to be careful about the "insides" of the machine, avoid meltdowns of parts and stuff, in this case I think it would be best to use galvos to drive the X and Y on the farther position as focus lenses can handle, yet a simple belt-driven X-Y system would also work, it's only about speed! smiling smiley

Definitely this would be something that I would put my effort into... I'm finishing my prusa and meanwhile I'm already trying to figure out a way to go "powder".

I think those milestones need to be reached to sinter aluminium, for example, I haven't said before, the insulated pre-heated chamber would possibly alow us to be able to melt and bond 2 layers at the same time with better control, the inert gas atmosphere to avoid oxidation and other build environment contamination, pressure leakages possibly could be a problem, the gas pumps,the vacuum pumps, and of course, a powder bed that also doesn't let powder go into threads, joints, motors, etc.. (a piston mabye?).

I mean, all this when dealing with aluminium, I guess. I don't actually know if it has to be that perfect, but when we think "Nylon" or "Teflon" it can get a lot easier, on the other hand we still need to deal with binders and stuff to get things going.

Regards,
Dz
Re: Aluminum (aluminium) printing
October 17, 2013 04:40AM
This is an interesting thread about using a 40W CO2 laser on some aluminium powder: [www.metalbot.org]

One idea to get rid of the oxygen (and therefore the oxidisation) is to 'burn it out' with a candle. But this does not get rid of all the oxygen...

Edited 1 time(s). Last edit at 10/17/2013 04:41AM by Hazel1919.

3D Metal Printing and more - visit [www.metalbot.org] !
Re: Aluminum (aluminium) printing
January 07, 2015 07:42PM
I think that the obvious solution to the Oxidization problem is to start with aluminium oxide powder, and fill the build chamber with hydrogen. Might even reduce the power of the laser needed.
VDX
Re: Aluminum (aluminium) printing
January 08, 2015 01:03AM
... what's the expected shrinking rates when reducing the oxide to aluminium?


Viktor
Re: Aluminum (aluminium) printing
January 08, 2015 02:55AM
Personally, I think that using lasers in a hydrogen filled build chamber at home is a not so great idea. I also have no clue how to calculate the change in volume, sorry.
Re: Aluminum (aluminium) printing
January 08, 2015 05:45AM
Though maybe the hydrogen idea is actually safer than the argon one. It seems that an argon leak from a pressurised tank in your bedroom would kill you: [www.cdc.gov]
VDX
Re: Aluminum (aluminium) printing
January 08, 2015 01:51PM
... I think, more people was been killed by hydrogen (+oxygen) explosions, than asphyxiated by Argon (with carbon-mono- or di-oxide this could be different) ... but either way round -- with inert or other gases you should use an oxygene sensor, reliable enough for detecting harmfull mixtures of the used gases.

I have some (pretty expensive) industry gas sensors, that can be switched to different measuring ranges, some of them related to Oxygene in Nitrogene or in Argon (have them programmed for the ranges some years ago) -- but this should be DIY-able with cheaper comercial oxygene sensors too ...


Viktor
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