Beambox minimum power setting and cutting paper/cardstock without burnt edges

Hi,

I have a Beambox and and while it cuts thicker material quite well, I have some problems with cutting paper or cardstock (200gsm). I just can’t get a cut with clean edges, they’re always burnt.

Things I’ve learned or tried so far:

  • My Beambox has a minimum power setting of 17%, below nothing happens at all, the laser doesn’t even turn on. Below 20% I get very varying results. Is this normal?
  • This leads to the problem that if I cut at 20% power and the maximum recommended speed of 20mm/s, the power is already too high for 200gsm cardstock. At 20% power it cuts easily at 60mm/s. At that speed the edges get a lot cleaner, but the the resulting cut path isn’t acceptible any more (it’s wobbly and start/end don’t meet properly anymore).
  • The focus lens might create a beam that is just a bit too wide for this application. However, even if there were other lenses (do you know of any?), switching the lens for a single job in which I cut paper doesn’t really make sense.
  • I’ve read somewhere that other lasers have a so called “dot mode” for this application. In it the laser basically pulses on and off very rapidly, thus simulating a lower power setting. Would this be possible with the Beambox and is it a feature that will come to beam studio anytime soon?
  • I’ve tried simulating the “dot mode” by creating a path with very tiny dashes (0.05 mm on / 0.05 mm off) and this definitely improves the end result at 30% power and 15mm/s. However, I don’t know if this rapid on/off is problematic for the laser tube? But isn’t engraving done in a similar way?

Do you have any other ideas? How do you cut paper / cardstock without burnt edges?

Thanks in advance!

Gonna preface all this with, I’m nothing official, just this guy that does stuff.

  • My Beambox has a minimum power setting of 17%, below nothing happens at all, the laser doesn’t even turn on. Below 20% I get very varying results. Is this normal?

Yes, This seems in line with what I’ve observed with my BeamBox Pro, it seems there’s a base level of power to get the laser to fire anything at all.

Also makes sense. That’s way above the speed limit of 20mm/s that’s recommended for vector cutting.

It might be worth the time to quickly double check and really dial in the focus to be 100% that you’re hitting the right point. Maybe set up a piece of cardstock at an angle so it should move in and out of focus as it goes from high to low. Cut on that and see if there’s any spot that gives you a tight enough beam. That will at least demonstrate that there is or is not a tight enough beam at the ideal focal point to make the cut you want.

simulating the “dot mode”

That sounds interesting. I wouldn’t expect there would be any harm to the laser, because you’re correct, that appears to be much like how the raster cutting works. If you were having problems with it leaving a dotted, not cut out pattern you could theoretically make a 2 or 3 color rainbow line alternating red-blue and then layer by color in order to cut alternating dots in 2 passes.

Theoretically, you could also experiment with cutting a white filled shape in raster mode, so that it sweeps back-and-forth, cutting at high power, but high speed. But that’s going to increase your cut times very significantly, like up to an hour. Granted that’s still going to be very low laser time because the tube is going to be off for the majority of the work time. But still a long time to babysit the laser.

I’ve also found that a lot of my burning is caused by either burning or reflections from the support material, whatever the cut is sitting on. Maybe try suspending the cardstock.

Final crazy thought. If you want the material to go directly from non-burned to vaporized, without overheating and burning the surrounding bits. I wonder how damp to wet cardstock would cut? If you misted the paper with water, would the focused laser power be enough to vaporize and blow away both the paper and the embedded water, while in the surrounding area, the energy of phase-change of boiling the water would be enough to absorb the stray power and prevent burning. Like I said, just a crazy thought that would be interesting to try.