Mylar - cutting multiple layers

[Kathy Burton]

I have a 45-watt Epilog laser and cut stencils from Mylar. Single layers are easy, but I need higher production so I'm trying to cut 2 or 3 layers at a time. After days of experimenting with speed, power and pulse rate, I'm still not happy with my results. The second layer is irregular or gets a burned/hazy edge.

I tried this before and got discouraged, so I'm wondering if it is even possible. Any success stories out there?

Thanks!!

[Leigh Costello]

HI Kathy,
I too would like to know if layers can be cut. I have mastered melting and hazing, now a clean cut would be nice.

Have you tried using a scrap of something like birch as a backing that would be sacrificed? (This just occurred to me, so I haven't tried this.)

Good luck.

[Mike Null]

If you're doing a lot of these a vinyl cutter might be a good investment.

[Joe Pelonio]

Not with mylar, but I was cutting multiple layers of laminating adhesive film for a customer. I sandwiched them between two sheets of card stock, taped to a sacrificial piece of 1/4" acrylic that had items cut out of it previously. I was able to manipulate the settings to get a clean cut with 3 at a time, though the edges stuck together a bit.

[Stephen Beckham]

Going GEEK here, but imagine the bandwidth of the laser beam... How many wave lengths can fit in the tiniest airgap between layers. I know it may sound star trek level 10 - but if there is even a micro thin slice of air -which there will be - the laser waves will diffuse between layers, causing the charring or burn edges. You can't expect to have the reaction of the focus like it's in the middle layer - that beam is beat up hard with the smallest of substrate - even a piece of tissue will diffuse the beam enough to cause a difference in etching.

The only thing I've been able to do is like Joe stated is sandwiching items and very tightly binding them - also had to over focus so the focus point was in the center of the layers. I found that the extra effort preparing the layers wasn't worth the time of hitting the go button again at the higher speed doing single layers.

I'm sure it's possible - IMHO it's kind of like 3D etching, nice to have, not worth the work/trouble in most cases.

[Peck Sidara]

Kathy,

I've found that cutting one layer at a time provides best cutting and edge quality. Reason, probably has a lot to do with what Stephen said.

Suggestions:

Place a peice of printer paper between each layer and try cutting 3-4 total mylar sheets at a time.

Try multiple sheets of mylar (4-6) at a time w/ nothing sandwiched in between. You'll likely get 2-3 good stencils while having to discard the top and bottom layers.

Above suggestions help... but there may be a little more cleaning up to do then expected and you may not like having to discard some of the layers (wasted material).

I've also found that air-assist doesn't help much with this type of application so try it w/ out air-assist (but be aware of possible flare-ups/catching on fire).

Mid range speed, low power, low frequency for one layer.

Mid range speed, mid power, low frequency for multiple layers.

HTH,

[Kathy Burton]

Lots of good ideas here and three that I'm definitely going to try tomorrow. Thank you for your expertise and for taking the time to respond.

-Kathy