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Greg Knight
09-28-2015, 11:06 PM
Folks,
Has anyone worked with cutting 1/2 basswood on a laser in 1 or 2 passes without leaving a lot of edge soot behind? The project is to cut a puzzle for carving and we have had a problem with soot accumulating in the kerf and getting over everything when carving.
Here is the recipe that we are using, and I would appreciate any suggestions or tests that someone might run.
Boss LS-1630 w/ 120w tube

Lens: 4" - focused at 111mm from top of lens
Speed: 5mm/s
Power: 65% of 95% of 120w tube
Air Assist to nozzle: 40psi
Exhaust Ratio: 25% Top of material / 75% bottom of material.

That is the minimum that we can get through without any issues. The Air assist made a lot of difference, and I am topped out on air pressure for the system so not sure if more air would make the difference. I am looking at upgrading the hosing but right now 40psi is about the top of the existing tubing so I can't tweak much more.



Any help would be appreciated!
Greg

Kev Williams
09-29-2015, 12:08 AM
Go back and try your 2" lens. With my 80w Triumph I've cut thru 1-1/16" cherry in one (slow) pass with my 2" lens, but it won't with the 3" or 4" lenses. Seems that the fatter beams of the 3 and 4 just doesn't have the heat.

John Bion
09-30-2015, 5:58 PM
Is Bass wood similar to Tulip wood? 1/2" Tulip cuts like butter with 2" lense on my 100w @ 75% power & 14 speed. The following image is a small project I completed today for a customer: 9mm Tulip laminated to 7mm Tulip and dyed. How mich air asist are you using? The more air the better. If you are only using the little air pump supplied as standard with Chinese lasers, do yourself a favour and get a proper compressor.
Kind regards, John

322518

Keith Winter
09-30-2015, 6:09 PM
Bass is soft like balsa wood if memory serves. Should cut easily. 4" lens is your issue never cut with that of you can avoid it. Use a 2.5" if it's available or a 2". I think you might try adjusting your ppi/hz as well. Not sure what they call that on your laser. Use a smaller lens then play with the settings till you get it right.

Keith Winter
09-30-2015, 6:10 PM
Beautiful John! How did you do the inset part, a cnc?

John Bion
09-30-2015, 6:50 PM
Beautiful John! How did you do the inset part, a cnc?

Thanks Keith,
I had offered either oak done on the CNC Router or Tulip done this way on the lasers. The Tolerances were very tight in this job, way too tight for wood in reality but one can only try to please a customer :) The Base had to be 7 mm thick and the Channel 9 mm deep, so I split the Tulip on the bandsaw, “thicknessed” it to these two specifications and then cut the Channel sides and the base from the two relevant pieces on the laser, marking the base with a kiss-cut so as to be able to align & laminate the internal channel sides perfectly.
Hope that made sense?
Kind Regards, John

Dave Sheldrake
10-01-2015, 10:46 AM
I think you might try adjusting your ppi/hz as well

It's a DC not RF Keith...no ppi / frequency adjustments available on those :(

Keith Winter
10-01-2015, 11:32 AM
It's a DC not RF Keith...no ppi / frequency adjustments available on those :(

I wondered about that. Controlling PPI/and Frequency is very handy, for example I can change the PPI from 500 for a lighter burn when engraving wood or to 1000 PPI for a darker burn on wood with my RF laser. When cutting, different frequencies work better with different materials on my machine.

Is there any kind of comparable adjustment on a DC machine that might help him out?

Greg Knight
10-01-2015, 10:11 PM
Thanks everyone! I was able to make the cut with the 2" lense and have a little less soot, but still wondering if there is a way to reduce the frequency of the laser so that I can reduce the heat but still make it through the material.
Also, all comments about getting rid of that dinky air compressor are dead on! I started with the 2" and little air, and the cut was pittiful. That is why I went with the 4" thinking that the focal length would make it through. The 4" will make it through, but like Kev mentioned the kerf is a little wide.
In between then and now, we talked to a laser fellow, and he mentioned the air, and he was dead on. It's all about the air. If anyone is reading this, and thinks air doesn't make a difference, they haven't seen what it does! Get a real air compressor and see what it does.

I am using laser cut software or RDWorks and I do see a adjustment for laser Freq (khz) but I haven't tried it yet. Any suggestions on a value to try?

Greg

Rich Harman
10-01-2015, 10:42 PM
I am using laser cut software or RDWorks and I do see a adjustment for laser Freq (khz) but I haven't tried it yet. Any suggestions on a value to try?

Don't! Freq and PPI adjustments are for RF lasers, not glass tubed DC lasers. Speed and power is all we have to work with.