corrugated cardboard

[Robert Walters]

Hey Folks,

I don't have my air-assist setup just yet, maybe by next week, but...

I've been trying to vector cut 0.150" corrugated cardboard and having the hardest time.
You know, the cardboard boxes all your toys/junk is shipped to you in =)

I can get through the top layer, I can get through the fluted layer, but there is ALWAYS that tad bit let of the bottom layers that holds on strong and just won't let go.

Even at 100% power and 30% speed on 5+ passes the sucker won't cut through completely.

I've even gone as far as making a couple of passes focused on the top layer, then raise Z axis up by 0.140" or so and go a couple more passes.

I'm even at the point now that it's starting to look like Ghost Rider with trailing ambers.

Humidity is a bit high, but I'd think after a couple of passes that would dry out.

I know some have mentioned that the plywood they are using now has a different glue and is becoming more difficult to cut, but the part that's still "holding" is not the glued areas of the corrugated cardboard.

Any thoughts or suggestions would be appreciated.

[Dan Hintz]

Start with the focus into the cardboard... doing multiple cuts and then refocusing is dong little more than if you had started that way. One pass should be adequate at a slow speed, but you're going to want/need air assist to cut down on the flame-up.

[Robert Walters]

Start with the focus into the cardboard... doing multiple cuts and then refocusing is dong little more than if you had started that way. One pass should be adequate at a slow speed, but you're going to want/need air assist to cut down on the flame-up.

Hi Dan,

That's what I've been doing...
Focus on the top surface, make a couple of passes, then refocus deeper into the material to cut the bottom layer.

I'll try again at much slower speed and see what happens, not worried too much about the flames at this time, just need to cut the stuff cleanly right now.

Just seems strange that I can cut 1/4" acrylic (abiet 1.2% speed), but can't get through corrugated cardboard!

[Tristan Ranatza]

Hi Dan,

That's what I've been doing...
Focus on the top surface, make a couple of passes, then refocus deeper into the material to cut the bottom layer.

I'll try again at much slower speed and see what happens, not worried too much about the flames at this time, just need to cut the stuff cleanly right now.

Just seems strange that I can cut 1/4" acrylic (abiet 1.2% speed), but can't get through corrugated cardboard!

I think what Robert is trying to say is that when you start to set the focus to about halfway through the cardboard, sort of like what you do with really thick acrylic when you don’t want to bevel the edges too badly.

[Robert Walters]

I think what Robert is trying to say is that when you start to set the focus to about halfway through the cardboard, sort of like what you do with really thick acrylic when you don’t want to bevel the edges too badly.

Nah, at this point I don't care of the edges are beveled, I just want a 100% cut out, not pieces hanging on with cardboard bridges.

[Dan Hintz]

Robert,

Reread what I wrote... I suggested you start focused partially into the cardboard... the very first cut should be focused into it. Acrylic works best this way because it acts like a waveguide and keeps the beam focused over a longer path. In the case of cardboard, you are attempting to cut two sheets of paper separated by an air gap, one of the more difficult materials to cut because of this. You'll have to go slower than if you were just cutting a single sheet of paper as significantly less of the laser's power will reach the lower sheet.

[Doug Griffith]

register the art between the 2 top edge corners of the cardboard, then flip the cardboard along with the art. Tolerances should be loose enough with cardboard for this trick to work.

[Robert Walters]

Reread what I wrote... I suggested you start focused partially into the cardboard...


Thanks Dan!
OH! Hawt Damn... it worked!!! I missed the "start in the middle of the cardboard" (obviously).

So, do this with acrylic too?
I usually get 90% through 1/4" acrylic on first pass.

Ironically, ULS Tech Support told me that I can't adjust Z with autofocus enabled. I just found that I could.

Again TYVM Dan, much appreciated!

[Dan Hintz]

So, do this with acrylic too? I usually get 90% through 1/4" acrylic on first pass.
Ideally, you want to cut acrylic in one pass, otherwise the meltback will clog up the cut line and create a rough edge. With a 30W, you're not going to get much better than 1/4", but by focusing in about 1/3rd of the way and slowing down a notch, you should be able to do it with one pass and a clean cut. The "1/3rd" rule of thumb starts to fall apart as you get past 1/2" thick material, but you're not about to get there with your machine.

[Robert Walters]

Ideally, you want to cut acrylic in one pass, otherwise the meltback will clog up the cut line and create a rough edge. With a 30W, you're not going to get much better than 1/4", but by focusing in about 1/3rd of the way and slowing down a notch, you should be able to do it with one pass and a clean cut. The "1/3rd" rule of thumb starts to fall apart as you get past 1/2" thick material, but you're not about to get there with your machine.

I'd just be happy cutting 1/4" cleanly in a single pass just to avoid the PITA factor.
If I can cut 1/2" using this method in a couple of passes, all the better!


I just found a quirk in my machine when re-homing Z (limit switch at bottom of travel) doesn't actually recalibrate Z for some reason and effects the autofocus too.

Anyhow... Thanks again Dan!

[Gary Hair]

Dan,
I have a 30 watt machine and cut 1/4 inch with no problem. I focus on the top and laser away. Granted, I use 1.2s and 100p, but it works fine. I cut through 1/2" using .1s and 100p and it worked amazingly well although it was painfully slow, but it worked.

Oh, and I don't have a "turbo-charged" machine, it measured about 35 watts when I checked it a few years ago.

Gary

[Dee Gallo]

Gary, I have a 30w Epilog and I cut through 1/4" cast acrylic with 4 speed/100 power/5000 frq. and get good clean edges. I never tried 1/2" but maybe sometime I'll try it!

cheers, dee