I have 0.25" cork sheets that I’m trying to cut.
Does anyone have settings or anything that could point me in the right direction?
I have 0.25" cork sheets that I’m trying to cut.
My experience with 0.2" thick cork. (The cheap stuff from Hobby Lobby.)
Use 200/50, 4 or 5 passes
Cork is really hard to cut.
- Slower than 150 causes fire.
- Faster than 250 doesn’t cut deep.
- Too much initial power causes fire, charring, and smoke stains. Keep it at power 50 or less.
- Even 200/50 4-passes barely cuts all the way. (Still need to cut/pull apart.)
- Cutting over an etched area causes fire and smoke staining. Cut first, then etch! (Or don’t cut near etched areas.)
The problem: Cork is a great insulator. First pass burns the cork and caramelizes the top of what is left. 2nd pass takes more power to get past hard caramelized area. 3rd pass needs even more power.
Cork also really stinks. You will smell up your entire building, even if you have a good vent to the outside. (My office mates have forbidden me from cutting cork on the GF because of the smell. Engraving is fine, but not cutting.)
Unless absolutely necessary, don’t cut cork.
For engraving/etching, I had great luck with 1000/10/225, dithered.
Works really well: just burns where the laser hits, no smoke stain. No visible rastering. (No masking tape needed.)
Your mileage will vary based on the type of cork, density, kind of glue they used, etc. As with all materials, get one piece that you can use for testing. These settings that worked for me may not be ideal for you.
I’ve had excellent results scoring/vector-engraving cork with s200/p5, which produces a nice black line.
Cutting the 1/4" thick stuff has been too slow to bother with.
If you have a simple shape, it’s quick and easy to cut with a razor blade around a laser-scored outline. Cork also cuts wonderfully with a router, so you could make a draftboard template and go around with a pattern routing bit—you can also use a light scored outline on the cork if alignment is critical. I’ve done both of these methods and it works great.
I outlined some cork cutting here:
I was dealing with .130” cork and a charred edge wasn’t a problem. I got through it in one pass, but it’s not apples to apples. I also found that engraves took less power than others have said.
You might be able to jig, cut, flip, recut to get through your piece, though that might be too flamey. Good luck and be careful.
I am trying to cut some custom gaskets with this cork sheet found on Amazon:
Product title: Cork Sheet: 12" Wide X 36" Long X 3/8" Thick, Single Sheet
The sheet received is actually 0.36" thick
I’ve tried numerous settings (150-250 speed / 100 power) with up to six cuts and its’ still not cutting all the way through.
Has anyone had any success with thick (it does seem quite dense as well) cork?
Part of the problem is that cork absorbs heat. Another problem is that cork is quite variable. I have cut cork that is much thinner than this at 280/full on a pro, but as others have stated it is really difficult to cut cork that approaches 1/4" let alone stuff that is thicker than 1/4". If you have any success, please share.
I have not had luck with that thick for the same reason @dklgood said, heat absorption. I instead use the GF to trace out what I want to cut and the I just cut it by hand.
I have an alternate theory: it’s the sheer volume of char that makes cork difficult. The char absorbs a lot of the energy and prevents the laser from reaching new unlasered cork in subsequent passes.
Whatever the cause, that’s pretty thick stuff and cork is not always very easy to get through.
My suggestion is to possibly do two things:
First, use full power, not 100. They aren’t the same, especially if you have a GF pro.
Second, if that doesn’t work, do two passes but do them one at a time so you can set a different focal height. I’d go the first pass at 0,36” and then the second at about half that, 0.18”.
I’d set the power at full and vary the speed in a proper material test as described in #6:
Good luck, as has been mentioned above cork can be difficult and inconsistent.
The laser is the wrong tool for this job.
It’s covered all the way to the beginning of this thread. It’s OK to score and engrave.
I think a big component here is that you don’t have any wave guiding. Or, at least, I don’t think you do.
Acrylic is the master of this and you get some effect of it in most wood as well, which allows you to cut deeper than the focal depth would normally allow. I think that the edge lit acrylic designs are a good example of this in practice.
Leather is a lot like cork in that regard. Thick leather can be really tough.
In a general sense, with acrylic and a lot of wood materials, you have the beam bouncing back and forth, or skipping, keeping it in focus (or relatively close) for longer than you would in empty air, or cutting a material like cork, leather, foam, etc.
The depth of focus, so to speak, for a 2” lens is only something like a tenth of an inch. The waveguiding effect is what allows for thicker materials to be cut pretty well without completely blowing out the kerf.
For the cork, or thick leather, I would try manually setting the focus somewhere in the middle of the material.
Got any good external resources about this? It’s sounds like an interesting theory, I’d like to see some sort of supporting experimentation about it.
The physics of exactly what happens when the laser hits your material is interesting, a mix of combustion, ablation, sublimation and incandescence at the least. Waveguiding is a whole other set of ideas, I’m curious.
Waveguiding is probably technically the wrong name for the behavior. Just how I remember the principle in my head. It’s actually called Total Internal Reflection. That phrase should pull up a lot more in Google.
That’s what I thought, too. Thanks for confirming. Oh well - lesson learned