Acetate Sheeting (overhead projector type)

Hey All,

I am attempting to cut some stencils using 0.05 - 1mm acetate sheeting (like what is used on overhead projectors) but it’s either not cutting all the way through (not even enough to pop out with pressure) or it’s melted the backside…

Any tips out there?

Appreciate you! Kate

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My thoughts:

  • could be you’re cutting through it, but the edges are melting and welding back together a it cools…?

  • completely transparent? Have you tried cutting it with a piece of paper as a backing?

Better responses will probably follow shortly…

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Welcome to the forum.

I make stencils out of material other than acetate, so I have no direct experience with this material. How are you trying to determine correct settings? Are you using a template file or just making wild guesses and adjustments? I think you will probably need a fast speed and lower power and you may need something underneath it so that it doesn’t make contact with the honeycomb tray.

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Acetate sheet is not suitable for cutting on the laser.

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To expand on what @dklgood and @linefeed are saying (I think they’re both exactly right): Generally the best way to cut things[1] is “fast and hot” meaning you want to blast what you’re cutting at full power and move as quickly as you can while cutting. This logic doesn’t work too well with really thin materials, the laser tends to overburn too much even at high speeds.

If I were you: I would pick a very fast speed (450 or so) and then do a material test to back into how much power it takes to get through it, and use the very lowest power setting you can while still getting clean cuts.

My testing method is laid out here in #6:

As for the idea that it’s “not suitable”, that may be true… but until you do a test like I described you won’t know for sure. Some plastics are definitely not appropriate – they melt too much or are exceptionally flammable or contain chemicals that can damage your Glowforge.

You’re in the clear about the chemicals with acetate, now you just need to see if you can find a way to cut it reliably and safely.


  1. There are exceptions to this logic but I won’t get into that here. This logic holds for most materials at ~1/8" thickness. ↩︎

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Welcome @strouddesigns to the Forum.
Here you will find a treasure trove of useful information that you can exploit using the search function. Many topics have been discussed through the years, and odds are your question has already been answered somewhere. Try to use specific terms in order to get the most specific and useful information, as we tend to discuss things all over the place.
For laser cutting stencils mylar sheets are a better option.
searching for “mylar stencils” yields these results:

Mylar Stencils

Good luck with your endeavors and I look forward to seeing what you are up to. Remember we inspire each other with our creations.

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Good to see you here. I hope you find your answer and share it with the forum. You will get to teach us a new technique.

I spent considerable hours on acetate sheets (and also polycarbonate) to try and create labels for spice jars, it just melts and burns and often does not cut thru at all. I ended up using acrylic photo “glass” available at home improvement stores.

It’s simply not an appropriate material for laser cutting.

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Do you remember what thickness sheets you had? It might be relevant.

No idea, came from Office Depot. Most of theirs on the site today is 0.003". It’s buried somewhere in my supplies. Barely thicken than paper, I remember that.

From what I’ve seen recently there are plenty of acetate sheets that are PVC and you don’t want to cut those.

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Might have been. Didn’t know better back then, but it’s been years. I think I gave the rest of them away. don’t appear to be buried in my stash.

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From Trotec laser hacks- they have one where a thick acrylic sheet is cut by putting it on wet paper towels. But the same principle could apply in your case, you could use settings to cut thru with the wet paper preventing melting (and welding) on the back side. https://www.youtube.com/watch?v=VLxj8GRrJys

Well then they’re technically not acetate. Good point, be sure that they are truly made of acetate.

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Acetate is not acrylic. Very different materials.

1/4" acrylic cuts like butter with the correct settings. 0.003" acetate does not cut at all, it just melts.

I’ve had good success with Mylar sheets (4 Mil). I’ve cut some SMD soldering stencils using it using the following tricks. I sandwich the Mylar between two wet sheets of paper and tape it down to the tray with painters tape (blue scotch tape). I then laser using the following settings.

Engrave at 390 Speed, 40% power, focus height 0.05, 270 lines per inch

Make sure that the sheet is attached well to the tray and if you have long complicated stencils, the extracter fan will slowly dry the sheets out. I’ve cut dozens of different SMD stencils this way without incident.

HTH.

Nick

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