I’ve seen a number of comments on how to cut acrylic with or without film paper still on.
Seems to be a mixed bag.
I can see the benefits of leaving it on to keep from damaging the face, is there any good reason to take it off either side or both before cutting…
Just getting started in this venture, have a Monport 130w coming and trying to beat
the learning curve a little…
So I thought I’d ask the experts…
thanks to all
Chuck
I leave it on or take it off depending on speed I am cutting, slow single pass I take it off just to reduce risk of flame outs.
I will be cutting 20mm Acrylic … so I think taking it off is probably best from your experience !
even with the 130W , it will still be a slower cut !
this helps alot…
thanks Chuck
Let me take this a step further…
I have the basic honeycomb bed for cutting…
but since I want to cut acrylic… and not wanting the reflctions to damage
the bottom surface, is leaving the bottom paper on good enough ?
( when I get the acrylic I will do some tests )
I dont like hanging the material off the bed, ie. final point of cut etc…
Seems like lying on a flat surface would be better removing the bend point at th end cut…
Also is there a material, ie. wood backing to lay the acrylic on that would work and not interfere with the bottom cuting ?
Lastly…when cutting… is it better to cut each piece as a separate part…
or can you use adjoining lines to save material. ?
ie… two squares next to each other, using the center cut line as part of the part cut ?
Why…I have 100’s of square/rectangular parts to cut and … again… laying flat would help using the center line cut with parts, verse hanging in the air and final cut bending down…
Thanks in advance !
If used correctly it is a significant time and material saving. I like to use it, also with acrylic.
Speaking of acrylic and protective film, if there are not too many small details I cut acrylic with protective film/paper.
…here I sometimes use very few and small bridges, works fine without special post-processing, and also saves some ruined items.
You have to test yourself with the length and power of the bridges for your material, usually, as little as possible.
hey Bernd..’
I thought about using a bridge…
maybe something like 0.05 - 0.10mm
Would need to experiment..
I use an Atomstack tray which seems to work ok for cutting my 10mm pieces…
but I do like the bridge method… will give it a try… 
I don’t cut Acrylic on a honeycomb bed anymore. I’ve read it collects the material and can catch fire. I just use the bed blades now and clean them every so often.
Yes it can and does catch a flame…
If I do cut mine the honey comb, I turn the exhaust fan on high, and also increase
the nozzle PSI to 10psi, just enough to push air thru the cut and keep the flame ups off
yet not so much to cool the cutting…
It is a dance that works…
yet the eyes and fire extinguisher is always looking and at hand…
and having a 500cfm fan pulling helps…
It’s an old discussion…, (my?) conclusion is, if you have a strong extraction, advantageously supported with compressed air (under the machine bed), the danger of gas explosion/fire is minimal. Put another way, ask those involved in the production of acrylic parts how often they have had fires in their machines.
One small flame early on in my cutting, none after working the formula out…
so… agree completely 
I get the best cuts with acrylic using minimal air, only enough to keep the lens clean. This was advised by Russ Sadler. I’ve used this for almost 5 years. Of course, I don’t cut anything nearly as thick.
A couple of videos about how it works with acrylic tells a lot… Many people love their honeycomb, I don’t think mines around anymore and I don’t miss it… it was aluminum anyway.
The first is < 4 minutes, the 2nd is < 16 minutes.. Just another view of things 
Russ uses honeycomb himself …
Jack, please leave this old discussion about honeycomb alone for God’s sake. We haven’t all bought a laser head from him or even had a tee with this gentleman, but we’ve all seen Russ’ videos and we all love this institution of laser knowledge on two legs…BUT
This is not about honeycomb but about fire in a laser machine and how clean and usable the items are after cutting.
I’ve described it before, and now again… During corona I’ve had the largest order in acrylic to date, I made stands for sight plates (also) in acrylic, all in 6mm. I made a lot of them, all on my new little 60Watt OMT this time. There was no fire in a single cutting process and the number of items I had to clean was honestly minimal.
I often work with 2 and 3mm acrylic, with protective film on both sides, with my industrial exhaust on full blast and proportionally adjusted air intake, it works very well here, no fire no dirty items - here, for me…
For my lamps I cut 0.8mm Aeroplan BB plywood. The sheets are 600x400 which lie directly on the honeycomb - it cannot be clamped or placed on punkspikes or the like… Here there is also no fire in my machine and the items are used without post-processing directly in the assembly, (it is almost impossible to wash or sand this material without damaging it).
The only time I had a flare up was cutting my 15mm acrylic, the slow cutting would ignite the gases…
poof.. a small flame, but as I mentioned that was in the early learning stages and as Bernd says
turn up the exhaust to max always… and this is a 130W running at about 50-60%power 2-4mm speed.
I also use shelf liners on those areas of the open bed to help block the air draw and allow more air draw in the cutting area…
I do use the punk spikes about 20mm above the work bed with some acrylic cutting, but i don’ like when the pieces drop and then get hit with the next laser pass because they did not drop straight down,
Hence the Bridge as Bernd mentions, which I will be trying…
I don’t notice that much bed build up with my acrylic cutting, but of course there is with Birch/Basswood.
Which, just last week I noticed it is time to clean the honeycomb, this will be the first time to clean after about 6 mo’s of use, mostly acrylic but the wood lately is gumming it up as expected…
I guess some Orange cleaner or Fabuloso cleaner which seems to work well on other items around the shop…
then some power washing… BUT I am open to a better method if anyone cares to share…
Seems like some type of foam spray that can soak for a few minutes… hmmmmm…
I try to cut as fast as possible, but of course it is always a compromise with how the edge looks. 6 to 8mm I cut with approx. 8 - 6.5 mm/s and approx. 32 - 40% power of my 60 (55?) Watt machine.
Is it 2-4 mm/s for 15mm acrylic? I have cut 15 mm, but it doesn’t turn out very pretty, my machine is just not powerful enough for that.
I also don’t clean my honeycomb too often, only when it starts to get sticky, HDF is the worst culprit here.
I use brake cleaner, let it work for an hour or 2 and then I use a high pressure washer with hot water.
