Have you tried painter’s tape? That sometimes help on the Glowforge. I haven’t had the opportunity on the Snapmaker yet, but I’d think it would be worth trying.
I am a newbie Snapmaker person. My first laser prints on wood, converting photo to wood etching, worked great. Then I wanted to create acrylic panel for LED light base. I couldn’t get the laser to do anything on clear acrylic. I tried different speeds and power settings. Consulting forum and YouTube, I tried paper, tape, putting dark stained glass on top or bottom of acrylic trying to focus on bottom of acrylic. I tried black window tinting material. Next I tried chalk marker as seen in a YouTube video. I got etching but uneven etching. I bought a can of spray on chalk from Menards that is supposed to be for kids creating artwork on sidewalks. I got good coating but I scratched up the acrylic trying to remove the chalk from the etched area. Long story short: I used scrubbing bubbles bathroom shower cleaner and rubbing with finger only, not fingernail, to remove chalk and that worked pretty well. But the etching was still uneven to my liking. Assumed again due to uneven coating. Then I tried dry erase marker which worked but my etching was streaky I assumed because coating was uneven or streaky. My etching was blotchy. I bought a bottle of dry erase marker refill ink and an ink pad and roller but the ink coating was better but still uneven. Then I bought some water soluble printing ink which seemed to give an even coating when wet. Trying to etch with this ink wet gave no etching. I assume because the wetness cooled the acrylic too much. When this ink was dry it too was uneven but better than dry erase ink. Etching was still blotchy. I watched the YouTube video of the guy who used original snapmaker to etch clear acrylic Darth Vader without any coating. I used 100% power (or so I thought) and 100 mm/min speed. No etching at all. I still have no clue how he made that work. Then I watched a video of guy who used white chalk marker and he got good results with sailing ship that did not seem blotchy. I stopped the video to see what his settings were. This led me to realize that by using the Gcode determined power setting checkbox I was only using 50% power. I unchecked that box and selected 100% power. He used 2 passes at 0.6 steps. I set up now to use 2 passes at 0.5 step and 100% of 100% power. I suspect that previously my controller was using 100% of 50% power. (Does that make sense?) My engraving time went from 40 minutes to 18 hours for same design; roughly 6"x10". Will let you know how this turns out. So, I have either embarrassed myself here or perhaps helped other newbies skip some hard earned lessons and wasting $50 of acrylic. Now, I need to ask which is better cast or rolled acrylic and how to I determine the difference?
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For the transparent acrylic, you need to cover it with a thin layer to reduce laser energy dissipation.
Just present an example of the transparent acrylic.
- Machine: Snapmaker A350
- Laser power: 1.6 w(100%)
- Work speed 42 mm/s
- Thin layer: Non-transparent tape
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Thanks! I am learning. I bought black contact paper from Staples that seems to be working well. Also using cast acrylic rather than extruded helps. My last trial was nearly perfect on the laser side but the laser also burned the adhesive from the brown paper protection film on the bottom side. The burnt adhesive melted into the bottom surface and ruined that piece. At the moment I am laser etching .25” cast acrylic with paper removed from both sides and the laser side (top) covered with black contact paper. Hopefully that works well. The black contact paper is much thinner than the brown paper that comes on cast acrylic. I am using 100% power and 100mm/min speed, 2 passes, 1 mm deep. If this works I will next try one pass at .5mm deep.
I am trying to make panels for LED light base for Christmas presents.
Rick Lyon
ricklyon135@gmail.com
what kind of black contact card are you using? could you put a link to purchase?
I tried some of the suggestions here (and in the PDF on the Snapmaker site), and as a first test, I tried to cut a piece of 3mm acrylic. With 100% power and 40mm/min (as suggested):
-Nothing on top, original brown protective material on bottom: No effect on top (as expected), shallow engrave on bottom with 2 passes, 0 stepdown between passes.
-Painters tape on top: Shallow engrave on top with 2 passes, 0 stepdown between passes.
I’m trying to figure out how to cut/engrave these for LED light bases, so as a first pass I wanted to get the settings to cut down the 12x12 sheet into smaller bits. Seems like the “cut” settings that SM documents aren’t going all the way through though. Next step is going to be to try some different whiteboard/chalk markers. Other questions for the group:
-Has anyone managed to cut 3mm acrylic with the laser, or is it better to just use the CNC for this?
-Is there a way to preserve the work origin between passes? Rather than program in multiple passes I wanted to just try running the same gcode again manually, but it looks like you have to reset the work origin. I suppose I just have to write down the coordinates next time-I thought it might remember the last work origin set (especially if you selected the same job a second time).
So I managed to get this to work with a combination of CNC and laser:
Solution was to create the logo as a vector in inkscape, create a linked offset path to get the outline, and then do the outline and engrave as two separate jobs. I did the outline using the built in CNC settings in Luban for acrylic, although I had to set the depth at least 0.5mm thicker than the material (and even then I didn’t get a cut all the way through on one side). For the engrave, I did 100% power, 40mm/min, and a vector image with one pass. I used a regular whiteboard marker to cover the side I was lasering, and it came off really easily with a combination of an eraser and some windex.
So from the looks of things, 3mm clear acrylic isn’t cuttable with the 1.6w laser, but you can CNC it pretty easily. I wasn’t sure how the edge would turn out, or whether the bit would melt the plastic, but it ended up fine on both counts. Only thing that was kind of a pain was making sure everything was lined up properly, since the boundary check on non-rectangular shapes isn’t immediately obvious, but that is solved by choosing the right origin.
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that look really nice! want to do something like this too. wich marker did you use?
hi guys , i have the ortur 20w and i have the same problem with the acrylic , are you using the lightburn program? because i´m tryign using differents setting and doesnt work 
i hope someone could help me please
Just a plain black expo whiteboard marker. Needed to make sure I covered the whole area, but worked great.
I created the images in inkscape and exported as SVG, then used Luban to print. Never tried lightburn.
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will it work with white Marker??
No. It needs to be something dark to absorb the laser energy.
Sharpie or dry moly spray lube also works. But with those you have to use alcohol to remove the residue.
-S
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damn it than I ordered the wrong ones 
Sharpie is going to be hard to get off. The black whiteboard marker comes off with a paper towel and some glass cleaner.
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Sharpie scribbles should come off with isopropyl alcohol, which a lot of us have around for use in cleaning print beds and such. There’s some on the shelf to my right. Our glass cleaner, on the other hand, is in a cupboard on a different floor of the house. So which is better depends on your setup.
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So i tried it today but the result is very bad. I did it with a green chalk marker and the settings from @cbardon . The green comes kot off and the lines are not clean
Its been a while since i used the laser and im not familiar with the new interface how do you set it up right
Looks like you’re melting the acrylic - too much power, and too slow. I usually run:
Work: 3000mm/min
Jog: 3000mm/min
Pass: 1
Depth: 0
Power: 50%
I have never used a chalk marker, so I don’t know if that affects it either. I’ve always just used a black dry erase.
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Make sure your ‘density’ is set to highest # (10 or 20 depending on mode). That way you get the highest resolution. (Thats in Luban V3s. They’ve changed what they call it and the numeric range is different in 4.0. Not sure what that corresponds to. One of several of the reasons I still just use 3.14)
I tend to do two passes whenever I’m using any type of coating (paint, sharpie, dry moly lube). I find the second pass burns away any excess residue that sometimes remains. Doesn’t always make a difference. Run tests if run time is important.
-S
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A few months back, I laser-engraved some clear acrylic (part of my make-your-own-ruler test to verify the accuracy of the laser engraver). I used white spray-chalk on the acrylic, worked fantastic. I was trying to do thin, precise lines, and did not want the acrylic to melt, so I kept power pretty low (somewhere between 10% and 25%) with multiple shallow passes.
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Did you do multiple passes? I only did the one pass, but at 40mm/min/100% when I did acrylic, but I haven’t gone back and tried again after that first one.
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