Durablack - power settings question for a CO2 system

[Ian Stewart-Koster]

I have the flyer and blurb from Durablack suggesting that about 15% of 100w is an ideal power setting, and not too fast...
When I tried it on either of our chinese systems, that was no good.
The crisp sample of Durablack work I have here, I expect was done on an RF laser, eg ULS/Trotec.

I've come up with about 33% Power, and 80mm/s and 0.075 line advance. (0.10mm was too coarse, and 0.060 was blurrier than 0.075mm per pass)
Lesser powers than 30% were just too brown in the background, not white, and greater ones had the edges melt more, for a bit less clarity when you get the magnifier or loupe out. The lower ones mentioned were way too light - or should I have slowed down much, much more?

I'm about to give it a try in the old ULS, but I was wondering if anyone had any updates that might assist me - I did a search and read old threads - no, not too much news...

Thanks!

[Kev Williams]

Try something along these lines:
drop the power to 30%, increase the resolution (decrease line space) to .045, increase the speed to 200mm/s... the hope is to keep the edges from melting while letting the laser overlap more on the straightaways to remove the brown... And with a 100w tube, increase or decrease your power in 0.3% increments, I've found with my 80w machine 1/2 percent changes are sometimes huge...

[Ian Stewart-Koster]

Thanks, Kev.
I did try the compound 38mm lens, instead of the 50mm one (on the Reci 100w tube), but it made scant difference to the quality or letter sharpness.

I chopped and changed speeds and powers - to no conclusion except I didn't really like any of them, much!

I ran a few on the old ULS and the clarity was beautiful, but still had some faint brown streaks at the edges of the letters if you tilted it in the light.
Going much slower didn't change it, not did dropping from ULS 1000 ppi to 500 ppi.

I'll try what you suggest - I'd like to be rid of that faint golden brown.

[Ian Stewart-Koster]

Wow! Huge improvement, thanks, Kev. The 0.040 interval or line advance I think was the best part, but I got the best burn at 200 mm/s and 45%.
Below 40 there was a browny tinge still - faint but there. Thanks heaps. I would not have thought to go to 200mm/s - though whether it actually achieved 200 is another matter, in the tiny test sample I did.