Thin material with 100W laser

[Patrick Shea]

We have an HL10060 machine 100w - Ruida 6445, and LightBurn Software. Trying to cut/etch some paper and not blow trough with the etch. Is there a pulse feature we can turn on? I think if we try to turn the power down too much, the laser will not fire- Correct?

Patrick

[Doug Fisher]

>> I think if we try to turn the power down too much, the laser will not fire- Correct?

Correct, CO2 glass tube lasers have a minimum power level for consistent operation. The exact amount will vary by tube, but many have a level in the +/- 10% range.

>>Is there a pulse feature we can turn on?

Are you thinking about something like dot mode that you can use in Line mode? If so, I don't know that this feature is available in Fill mode within LightBurn.

[Gene Uselman]

Etching paper may be dicey- use low power and high speed. Air assist is also going to take some experimentation.

[Charles Jones]

Engraving paper using the dithered graphics mode in RDworks is pretty good. Not sure if this is what you meant by "etching." I was able to get 254dpi on card stock by moving fairly fast with very low power using just a standard lens. I'm sure that someone with a compound setup might be able to do even better. I watched Russ's video on photo engraving and then used his test pattern which helped find the ideal settings. I made a matrix of tests and just tried a bunch of permutations until I had something that worked on my machine. I started with a 2.5" lens at the nominal focal point and then tried different speeds/powers to see what worked best.

Most importantly, I learned to lower the material several mm BELOW the nominal focal point. As you might have noticed in Russ's exploration of lens focal points, because of the spherical aberration inherent in the lens, the center of the beam which had higher power density focuses at a different distance than the outside of the beam. As such, if you are below the nominal focal point, then the central high power beam is actually in focus and the outer lower power portion is out of focus and getting more diffuse as you go lower. If you just pulse the beam on a spot, you'd cut through the paper with the center of the beam and char a large circle around the hole from the out of focus wider part of the beam. This is where moving at high speed is important. If you move quickly enough, the center of the beam has time to burn a very very small black dot without cutting through the paper, but the wider diffuse region of out of focus beam doesn't have any chance to do ANY DAMAGE AT ALL. This can be used to make very high precision engraved images on any material just by finding the right deep focal distance and speed. No fancy lens work necessary.

For my machine, I ended up using 8% power which is my absolute minimum, 160mm/s and about 5mm below the nominal focal point on a 2.5" lens. 1.5" lens didn't make any improvement. The 160mm/s was a compromise between getting nice black dots and starting to miss dots.

[Charles Jones]

Forgot to mention, I have a 130 watt machine, so I think the results apply to your question.

The photo with the micrometer shows how the size and spacing of the 0.1mm dots worked out nicely at 160mm/s, however I did start to miss a few dots at that speed. An acceptable loss at 254dpi.

I don't have a microscope, but in a pinch, the 2x optical zoom combined with the 10x digital zoom in my smart phone camera allowed me to get some pretty good pictures of the small dots.