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Metal Matters SLM Printer - Discussion
#1
Thoughts and opinions.. Post them here
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#2
First, amazing work.
Second, have tried pulsing the laser to give dots and not lines, say 10mm/s and 10hz at 30-50%?
Third, what depth of material to layer thickness do you use? i suspect a lower powder depth may reduce pull in from the sides.
Fourth, have you tried perimeter first with the slicer to get less pull in on the boundary layer
Fifth, i like your laser focus, but i just do a 100mm line and drop 10mm through the line to get the focus point
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#3
Hi,

just want to say hello...and want to wish this project a bright future...realy amazing work!!

Will follow regulary...

Thank you for doing this...

Torsten
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#4
Where do you get your steel powder from? Would a blended aluminum foil be a viable option for a DIY crowd? Also have you tried using aluminum powder for your tests?
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#5
(01-17-2021, 11:29 AM)Bruce Baxter Wrote: First, amazing work.
Second, have tried pulsing the laser to give dots and not lines, say 10mm/s and 10hz at 30-50%?
Third, what depth of material to layer thickness do you use? i suspect a lower powder depth may reduce pull in from the sides.
Fourth, have you tried perimeter first with the slicer to get less pull in on the boundary layer
Fifth, i like your laser focus, but i just do a 100mm line and drop 10mm through the line to get the focus point


Thanks! I responded to you on YT but will add something here..

I'm not sure how suitable these lasers are in regards to pulsing them. I suspect they are of a high capacitance and may need an H bridge to be driven as you describe, probably shortening the lifespan of it severely. In their intended application (projector systems) they are not switched.

I have the same suspicion regarding the height of the powder. I think it might be a case of applying as finer layer as possible to permit the laser to move over it quickly so the region being melting doesn't experience saturation in terms of heat. In theory I have been applying coats of 0.06mm but until the powder bed issues are resolved I can not definitively say this.

Yes, perimeter first actually creates more issues than it solves. Jury is out to lunch on this one. I suspect heating a zone and then reheating it only extends the reach of the molten track.

I am aiming for repeatable parameters in regard to focus but I like your method!
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#6
(01-18-2021, 01:06 AM)Montec Wrote: Where do you get your steel powder from? Would a blended aluminum foil be a viable option for a DIY crowd? Also have you tried using aluminum powder for your tests?

I source my powder from metalpowders.com.au. I would suggest staying away from Aluminium as a beginner material as it is very reactive, toxic, and potentially explosive!
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#7
I love what you are doing and think you might have just messed up my plans for a CO2 laser build. You have fiber or the 20 array in the laser section did you build one with both, if so what direction would you recommend. I'm gonna use a belt drive Ox Heavy duty that had a 1.5kw water cooled spindle so weight wouldn't be a issue, lol, also water cooling still attached. Again thanks for starting this place, I've been thinking about metal a week after I picked up my first 3d printer years ago.
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#8
Glad to hear it!

I have only built a system using the 20 element array. I had a fiber system until I damaged it by not aligning the fiber properly. If I were to recommend one system over another it would be the diode array as it is relatively robust. I think the appeal of the fiber laser is the weight of the head. In theory you should be able to move it quickly, only limited by the speed of the supporting framework or power density of the laser itself, but I am not sure if a fiber will tolerate repeated movements as they are quite brittle.

I have another laser coming soon that I want to experiment with. I suspect I will be able to achieve a much tighter focus with it. It's also smaller and produces less waste heat. We shall see what becomes of it.
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#9
This is so cool. What is your background in engineering?
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#10
Possible spreader design upgrade.

So as far as I understand you changed from a round surface spreader to a sharp edge spreader from front and back. What I suggest is to have a sharp leading edge that would spread the powder equally on the surface and a rear end round surface that would help compact that remaining powder. Usually hybrid methods lead to best solutions. Let me know what you think @Junkers
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