(not) Cutting 1/4" Cork Sheet

[daniel coyle]

I have a 130W chinese laser and am trying to cut 1/4" cork on it. I run it at 80% (30mA) and 15 speed and results are variable. Ideally it would cut well enough that the pieces would fall out but that is rare and it is not uncommon for it to not cut all the way through. Depends on where in the field it is but it makes no sense to me. I have played around with the focal length and have tried to double cut (that does not work). Seems like if I go too slow it starts to char more. Could it make a big difference to put an additional air source on it (It already does have one).

Anyone have experience cutting thicker cork?

[Dave Sheldrake]

Density varies Danny, I try to avoid cork like the plague

[Joe Pelonio]

Density varies Danny, I try to avoid cork like the plague

I found that too, but have cut it with just 45 Watts, doing 2-3 passes, at a faster speed, with 40 lbs. air assist, and misted with water before starting.

[Mike Null]

I agree with the previous comments but I would try focusing into the material by about 1/16".

[daniel coyle]

What does the water misting do Joe? I will try that, along with doing multiple passes at reduced power and increased speed.

[John Lifer]

keeps it from burning.... Cork is bark and is extremely variable.

[daniel coyle]

I also, no matter how much I play around with it, can't seem to get a really crisp cut line on the cork that tells me I have the focus spot on.

[John Lifer]

It's like any other material, measure to focus, maybe shorten the distance to have true focus below the surface. But again, it just won't be super clean cut due to the material.

[daniel coyle]

Misting with water did seem to help. Still not getting great results (ideally the cork pieces would just fall out after cutting and I wouldn't spend good time manually popping each one out). Doing multiple passes hasn't improved anything yet. Increased the speed but the second and third passes did not appreciably improve the cut.

[Matt McCoy]

I would suggest dialing-in the settings to allow just one pass, good air-assist, transfer paper on both sides, and a clean lens.

The type of cork really matters too (large grain, small grain, etc.).

[Trey Tull]

I have had pretty good luck with cutting cork. When I get back to the office, I'll look at my settings and get back to you.

[daniel coyle]

Thanks Matt, what does the transfer paper help with? I am more concerned with actually cutting through the cork than I am about aesthetics (some burn darkening is acceptable, its for function more than form)

[daniel coyle]

I have had pretty good luck with cutting cork. When I get back to the office, I'll look at my settings and get back to you.

That would be great. I know that working with 1/4 inch cork has been much more challenging than any 1/4 inch woods I have tried cutting. I would take it to a water jet if it wasn't so expensive.

[Matt McCoy]

Thanks Matt, what does the transfer paper help with? I am more concerned with actually cutting through the cork than I am about aesthetics (some burn darkening is acceptable, its for function more than form)

Discoloration on the front and back of the cork.

That would be great. I know that working with 1/4 inch cork has been much more challenging than any 1/4 inch woods I have tried cutting. I would take it to a water jet if it wasn't so expensive.

You might be able to stack several layers of cork on the waterjet.

[Kev Williams]

About focusing below the surface-- when cutting, you want your beam spot at its maximum power density. Because the beam is tapered, max power is achieved at the point where the beam reaches it's smallest diameter, and you want that point right at or just slightly below the surface of what you're cutting. As you cut, the kerf is only slightly larger than the focused beam spot. So, if you focus a good distance below the surface of the work, the wider sides of the beam will be partially blocked by the edges of the kerf. That blocked light energy is lost, never reaching the focal point, substantially reducing the beam's max power density. Any possible gain in cutting power by focusing lower into the cut is likely more than offset by the unfocused light being absorbed. The power density falls off as the cut moves deeper anyway, focusing lower just gives the power loss a head start

Focusing a snick under the surface is okay, just stay within 1/2 of your lens's depth of field. Longer 3" and 4" lenses have much less taper and longer depth of field than 2" lenses, so they allow for more wiggle-room than a 2" lens would...