G’day everyone, i have got some DMLM experiments planned and was wounder if anyone here knew the best place i can gets my hands on 1kg of 3D printing metal powder. i’m looking for aluminium or brass, as i’m hoping that will require the least about of Laser wattage.
try stainless steel. aluminium and brass and copper dissipate heat too much.
@marc_kerger i think you might have a point there mate.
In the mean time, why don’t you pop that machine open and let us have a look eh?
@marc_kerger im not sure but i would more concerned about a metal that have a high absorption in the wavelength of my laser.
The head dissipation I would suggested is secondary ?
But that’s only my opinion
@Jon_Gordon you probably already gathered that this is currently just a minimum viable test,
but here you go. https://photos.google.com/share/AF1QipNJx5XDwXTcH7UY9LHuFpJjeDR4E1qrQ1o6V9pmSzTrKO_X_R7KgAp0hclh-X619A?key=QmpnVlhCaFB0c3BDQmZHRnBZWTVKa2pwUXVHcldR.
the plan is to spread the powder manually with a ruler or such, and just keep adding a spoonful of powder each time you lower the bed.
@william_foster Thanks! You know I’m not the only one thats curious.
You might see if there are any companies making powder metal components in your area? They are most likely going to be working with steel powders, but they might be interested in a partnership, especially if the initial investment is only a couple kg of powder. The Metal Powder Industry Federation http://www.mpif.org/ might have some useful information.
@Sebastian_Schmidt that’s probably my biggest concern currently. Co2 lasers, which is whats most accessible to me. loses heaps though reflection with aluminum. i should probably use plain steel powder in that regard.
My understanding is that commercial sintering systems use heated beds so that the laser just to raise the temperature of the material being used by a few degrees. That lets you use a lower power laser than otherwise. However, it wouldn’t be compatible with a printer made of plastic of course :-). Without that heating, I’d expect a lot of warping.
Are you planning on using any kind of shield gas? Oxidizable metal powders like aluminum and steel are violently flammable. Depends on particle size, laser energy intensity, etc. I don’t know if you have the conditions to ignite the powder, but you should probably do some research on that.
@Ryan_Carlyle flammability depends to big part also on particle size.
And if you need a shield gas maybe a cheap way would be CO2
Flour and yeast.
@william_foster maybe looking for the right powder can help.
In example smaller particle sizes tend to be gray and if they got smaller that goes to black.
@Sebastian_Schmidt Aluminum can burn in CO2. It will strip the oxygen off practically any other molecule. (That’s how thermite works – pulling oxygen from rust.) There’s a good reason laser-melting systems use nitrogen or argon.
@Ryan_Carlyle i’m not totally sure i will have enough laser power to get it to do much anything, but i have a bottle of argon on standby in the case that it does not work in an open atmosphere.
they put argon in double pane windows because it reflects far infrared. May not be the best choice of shield gas for an infrared laser.
In order to sinter metal with CO2 lasers, you need to bring the metal power up to a temperature just a degree or two below it’s melting point… that requires a tremendous amount of control over the heat.
You also need a system to keep the metal pure and make sure you do not come in contact with it, as the particles are very fine and can easily leach into your body. You can also breath them in, which is also very bad.
I’m pretty sure that plastic chamber won’t hold up to the temps required. 
There’s an Arcam at my work and the chamber is heated to 700-800C. It uses an electron beam in a helium filled vacuum chamber to sinter the titanium powder.
check out the matterfab, they produced some pretty decent looking prints without a heated chamber.
If its a helium filled chamber, then it is not a vacuum. Why not just use a vacuum chamber?
@william_foster , I might be able to hook you up with some real DMLS powders in steel and bronze, or even a whole DLMS printer without control software if you would be intrested
We crowdfunded a working used Eosint M250Extended with 100kg+ of powders for our Makerspace two years ago but the control computer hard drive crashed in the transport and we moved since then, and our new space does not fit the printer so it is just sitting in storage, so we cant even try to get it working again…