type of laser for sls

Hello!

I'm engineer from Poland, and I'm representing a group of 3D printing community. Our last goal is to make SLS printing machine for our work shop. We manage all issues with feeding pistons and printing bed. But we've stuck on laser beam. There is very few information how to control the laser beam, also what kind of laser is best for SLS printing - in this case for plastics. My question is that anybody can share some knowledge on this topic?

Of course we have read all information and we are familiar with opinions that home-made sls is impossible to make... But however we decided to give us a chance on this project.

If You want to share some knowledge or You have similar issues please contact me on formowniki (at) gmail.com !

... you can melt plastics with any laser that outputs more than some hundred Milliwatts of power -- but the laser energy has to be absorbed inside of the plastic particles!

So try to get some IR-diodelasers with 808nm or 975nm and >5Watts of output power (and protective goggles for this wavelengths too!) and use dark plastic powder or mix bright powder with some carbon black ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Old school CO2 tube lasers are the cheapest and easiest. The IR wavelength they output is perfect for even plain natural nylon powder. Other lasers will need to have the nylon powder doped with carbon dust or laser toner in order for the different wavelength to be absorbed correctly.

Last few days I was looking around the net and I was trying to collect all puzzles in on. So please can somebody ( VDX?) review is possible to combine all below in SLS printer:

1) [pwdr.github.io] - for powder distribution. Of course we need close chamber so it need to be changed. But for base I think is OK.

2) [www.sintecoptronics.com] laser marking system based on model: M-UL-50OEM

3) [www.lasermarkingsoftware.com] software with Z-ax control. I have no clue how it that compatible with M-UL-50OEM

4) [www.onsitegas.com] while we are gonna sinter powder, it the chamber has to be continuously supply with neutral gas. So whatever we buy it will be OK. Of course withe proper parameters.

So what do You guys think?

... 'pwdr' will give a good basis - even better, if you have linear XY moving.

For a galvo-scanner system a radial wiper would be easier to build and easier to enclose/shield with inert gas too.

If you have a galvo-driver already included with BeamConstruct, this would be fine ... otherwise you'll need a programming license what's 500€ per year.

Argon would be the better gas for shielding -- N2 is cheaper, but can be problematic when sintering metal alloys and ceramic-polymer compounds ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Victor

thanks for rep.

First what is "radial wiper"? I'm not familiar with this.

About galvo scanner and software. Do You know some solution how to translate 3D CAD model to galvo scanner? Is such thing on market or I have to wrote my own software? The thing is to send instruction to printer: everything is OK, inert gas pressure is in, doors ale locked, temperature is OK so You can put 1st layer, scan, next layer, scan, next layer etc. I think it will be necessary to write own BIOS for machine which will manage the temperature and doors and inert gas. But the thing is how to translate specific slice to galvo. I don't think that there is something like Cura or Kslicer for SLS machines...

... in most of the DIY-powderbed systems a linear wiper is pushing and evening the surface by moving back and forth -- in a radial setup this wiper will move like the arm of a record player, what's smaller in footprint and easier to build for a small powder bed area.

I think, you can use most RepRap slicers with adjusting the line width (and/or scaling factors) for creating the slice images ...

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I have found such N2 generator: [www.ebay.com]

What do You think? Is that sufficient for lets say 210x210x210 building volume? On the pro sls printers there is only compressed air consumption and that is for N2 generator.