Laser cutter for 190 Mil Mylar

[April Fregd]

I own a successful stencil company for face and body painters. Right now I cut on Graphtec 6000 with a blade. I am tired of picking mylar parts out.

I am strongly thinking of a laser cutter but need good clean smooth edges, detailed cuts that can be thin. I can't have burn marks on the stencils as painters want perfection.

I would like air cooled with an exhaust but after that, I don't know what I should be looking at. I cut a couple thousand stencils a year.

What suggestions do you have for a cutter and tips for cutting?

[Mike Null]

Do you mean 190 micron?

[Lee DeRaud]

Just so no one freaks out, you mean 190 micron, right? That's about 7mil, which sounds a bit more reasonable for stencil work.

[John Blazy]

I looked at this thread because I have been searching for optically clear PET thicker than 14 mils for years now (would love ARPET in 15 or more mils), and to no avail, so 190 mils is insane - obviously a typo, but got me excited anyway.

I cut 10 mil PET all the time for premasks and test cuts with my laser, and although accurate and leaves a decent edge (for my needs) it likely will not deliver what you need. The smoke leaves a grimy residue, and can be lessened with a pin board (I made a nail board with my framing nailer for greatly reduced underburn / smoke, etc).

If you get PET with masking both sides (or at least the back), then you will eliminate the burn residue, but then you have to demask. Can't see how a laser will stop you from picking parts out - you need to weed anyway, but not sure what your plotter leaves - apparently it cuts, but leaves the part stuck to the backing? Laser will cut right through nice.

Whenever I cut my 10 mil for a stencil, I just wipe it with lacquer thinner, and it removes most of the grime. With the right settings, (barely cutting through) it eliminates nearly all burn, and if the back is masked, then its pretty clean, but not sure your standards. The edge has a tiny micro melt burr. Doesn't bother me.

[April Fregd]

So many months later I come back still considering a laser cutter. 190 Micron as stated. I am sorry for the confusion. When ordering my mylar to spec from Germany they state it as 190 MIL.

I am going to buy a laser cutter in the next 30 days but don't want to make an expensive mistake.

[Kev Williams]

I laser cut some 1 mil and 1.5 mil mylar gaskets a couple of weeks ago, using water as a heat sink-
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My customer couldn't use them because-- the edges weren't smooth enough. I cut them at like 10% power (40w Synrad) and 15% speed, they looked great, until you got them under a 20x loupe. Just too much melt, even with the water helping.

[Lee DeRaud]

I laser cut some 1 mil and 1.5 mil mylar gaskets a couple of weeks ago, using water as a heat sink-
My customer couldn't use them because-- the edges weren't smooth enough. I cut them at like 10% power (40w Synrad) and 15% speed, they looked great, until you got them under a 20x loupe. Just too much melt, even with the water helping.Is it the quality of the cut path that's at issue, or does the cut edge have enough thickness variation to make it a problem in that application?

[Kev Williams]

As small as these are the cut paths of the screw holes do leave a little to be desired, but the thickness variation due the slag is the problem.

[Lee DeRaud]

I laser cut some 1 mil and 1.5 mil mylar gaskets a couple of weeks ago...Upon further review...did you mean 1 and 1.5mil or 1 and 1.5mm?
Not sure I've ever seen 1.5mil mylar, much less cut it, but those settings are higher than I use for 7mil on a 25W machine.

[Dave Sheldrake]

Frequency doubled 1,064 fellas, CO2 is the wrong wavelength for Mylar

Most of my Mylar cuts are done with a 532 nm to get a clean edge but if you do give it a go, 532 is likely the most dangerous of all laser wavelengths, it's right in the middle of the visible spectrum and you need very little power to blind yourself. They make those aweful BluRay things look safe. Cheap diodes leech as much as 30% IR as well as the green too so dedicated lab style sources work the best (but are also the most expensive)

[John Blazy]

So many months later I come back still considering a laser cutter. 190 Micron as stated. I am sorry for the confusion. When ordering my mylar to spec from Germany they state it as 190 MIL.

I am going to buy a laser cutter in the next 30 days but don't want to make an expensive mistake.
I think you will be happy with a laser. I can't imagine body stensils requiring the perfect edge that gaskets need. I cut PET (Mylar) all the time, and the tiny lip on the edge doesn't bother me. You often can't even feel it. Speed of cutting the mylar is great, and you will find a ton of other uses for the laser like cutting thin wood / plywood, acrylic, thick paper, etc.

[Kev Williams]

Upon further review...did you mean 1 and 1.5mil or 1 and 1.5mm?
Not sure I've ever seen 1.5mil mylar, much less cut it, but those settings are higher than I use for 7mil on a 25W machine.

Look at my 3rd pic above, you can just make out the sheet size, 10 x 20 x .0015, and this amber colored is the .001...
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I probably could've gotten away with less power, but initial testing with both sides transfer taped required more than 10% power. I thought the taped ones were okay but my customer said the water cut was better. And getting transfer tape off of .001" thick anything, what a trick!

[Matt McCoy]

Frequency doubled 1,064 fellas, CO2 is the wrong wavelength for Mylar

Most of my Mylar cuts are done with a 532 nm to get a clean edge but if you do give it a go, 532 is likely the most dangerous of all laser wavelengths, it's right in the middle of the visible spectrum and you need very little power to blind yourself. They make those aweful BluRay things look safe. Cheap diodes leech as much as 30% IR as well as the green too so dedicated lab style sources work the best (but are also the most expensive)

April: If you want to cut Mylar stencils with a CO2, good results can had pretty consistently after settings are dialed in. Perfectly fine for body art applications and Mylar is listed on Epilog's website as a suitable material.

I did notice a section on your website dedicated to licensed characters. If you haven't already, you might consider looking into obtaining the necessary intellectual property rights to use those, to avoid any potential liability of putting you and your business at risk.

[Dave Sheldrake]

At the bandgap of Mylar CO2 is a photothermal cut,thats what rolls the edges. If you want perfect results you need a photochemical action if you want to break the molecular bonds of mylar, thats going to require 532nm or 445nm, 532 has a photon energy of 2.33 eV, 445nm has a photon energy of 2.78 eV. Mylar has a bandgap energy of 1.9667 eV so CO2 with it's bandgap energy of 0.117 eV will always be a photothermal action hence rolled edges and a melt effect.

Short version, can you cut Mylar with a CO2 laser? yes, will it ever have a perfect edge...? no

[Matt McCoy]

At the bandgap of Mylar CO2 is a photothermal cut,thats what rolls the edges. If you want perfect results you need a photochemical action if you want to break the molecular bonds of mylar, thats going to require 532nm or 445nm, 532 has a photon energy of 2.33 eV, 445nm has a photon energy of 2.78 eV. Mylar has a bandgap energy of 1.9667 eV so CO2 with it's bandgap energy of 0.117 eV will always be a photothermal action hence rolled edges and a melt effect.

Short version, can you cut Mylar with a CO2 laser? yes, will it ever have a perfect edge...? no

Really cool -- thanks for the info.

[April Fregd]

Thank you for the information. In the end I have kept cutting with my Graphtec plotter. There is person in Germany whom I have bought stencils from years ago. I hope to go visit him to see what machine he has. I did write but of course he never responded, as expected.

I don't want to make a 10K mistake.

[John Blazy]

April,
You need to post photos of the type of detail that your plotter can make as a comparison. I would believe that a laser can easily match the detail you need (can easily cut detailed letters like what you are reading here), yet still be easier to weed out that a plotter cut stencil. All this talk about the rolled edge of laser cut edges is likely not going to be an issue, and can actually be helpful in stencils, as the tiny (I mean barely discernable) lip might actually help prevent "bleed under" of paints.

The tiny melt lip of laser cut mylar is bad for gaskets, but I can't imagine bad for application on human skin. Nice thing too is that you can apply a low tack adhesive to the mylar for sticking it down. Can your plotter cut through mylar with PSA adhesive on back? Likely clog your knife.

[Matt McCoy]

Good luck with your search.

A laser will work great for mylar stencils, especially with an airbrush. While an adhesive-backed stencil sounds like a good idea, they get pretty dirty with heavy use (hair, etc.)

[Michael Hunter]

If you ring the laser manufacturer or their agents they and explain what you are trying to do, they should be happy to send you a sample or even cut a piece to your own design.
(if they are not helpful, you won't be buying from them will you?)
Trotec in the UK seems to have a big department providing demos and samples to support their sales efforts - I'm sure it will be the same in Europe.

I have made stencils and masks with very fine details with my laser. Yes - the material thickens right by the cuts because of melted material, but this is microscopic and for nearly all purposes the results are perfectly acceptable.