Laser engrave/cutting for clear acrylic

I saw this guy was able to engrave directly on a clear acrylic
https://www.youtube.com/watch?time_continue=208&v=uwkPZETgdlc&feature=emb_title

I just tried using the following settings on a Snapmaker 2, but couldn’t engrave anything on a clear acrylic.

  • The laser module is 1600mw.
  • Work speed 1000 mm/min
  • Fixed power 100%
  • Used auto-focus, didn’t adjust focus manually
  • Used camera capture, then place the vector graphic file on top of the work area.

pretty much nothing appeared on the clear acrylic… any suggestions?

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I have same question. I’ve tried to cut and engrave clear acrylic board 2mm thick. I could engraved it but only back side , not surface.
About cutting , almost nothing has been done.
I’m doubting focus setting, but don’t know how to solve.
Please kindly advise.

my setting is as below.

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Thanks for your response.

I just tried again using the suggested setting for engraving, still nothing. I did observe that the laser beam appears to be going through the clear acrylic (I used 3mm) and the light dot is on the black aluminium workstation. I’m curious how you could engrave the clear acrylic?

I guess I should mention that I didn’t use a black marker to pain the acrylic surface since I want the engrave to come out as white instead of black. Just like this picture from the Snapmaker official website.

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Maybe this post helps:

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The 450nm laser won’t work on clear acrylic (PMMA), because PMMA doesn’t absorb above 400nm
(see absorption spectrum for PMMA) PC, PET and PVC won’t work for the same reason. A good trick is to look up the UV transmission/absorption diagrams of the material and choose it accordingly. After a quick search I found some transmission diagrams. (bad quality but readable)


https://www.idec.com/auen/technology_solution/our_core_tech/images/264_image001_en.jpg

You can either choose a different material like PP or HDPE or you can coat the surface with paint (white should work too, but might need more power / time)

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Thank you for everyone’s feedback. One easy fix I found was to place a piece of paper either on the top or bottom of the clear acrylic, that way the engraving can be done.

However, as the laser burns through the paper & acrylic, there are tons of black residue / charcoal left on the final product. I try to wash it with a toothbrush but can’t get all of them off.

I’m interested in creating a white engraving picture like this one below, any idea how it can be done? Much appreciated!

I tried to use a laser on the transparent acrylic board before. I use the white paper to cover the acrylic board and it worked.

I made different tests. The first time, I just put the paper on the acrylic board and without a fixture, and the paper did not stick to the surface of the board, there was a gap between the paper and the board. The result was very good and there was no much black residue. The second time, I use glue to fixed the four corners of the paper and there was no gap. The black residue stays on the board forever.

I guess my experience may help you in some way.

Regarding the picture, I guess it could be created by the CNC module?

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Hi Potter,

Thanks for your comment. I will test the paper on top approach again, in my previous testing, there was black residue on the board in either approach (on top/at bottom).

I thought about using the CNC module to achieve that, I guess I’ll have to use the V-bit for finer details. I’ll try that later today… Since I also need the final product to be cut out of the bigger acrylic board, might as well use the CNC for engraving too!

Yes, you should use the V-bit. And a slower work speed would lead to a better result.

What work speed would you recommend for acrylic engraving?

I use a chalk marker which is normally used on a white board, its like a chalky paint in a marker pen (surprise!). I use a darkish colour to ‘paint’ the area I’m etching. The paint just washes off very easily and leaves no residue in the acrylic.

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Snapmaker is using that particular picture (in multiple places on their site) as an example for laser engraving, not CNC, so it is a bit weird if it in fact cannot be done?

I have been doing some work with mine engraving clear acrylic with mixed results. Basic clear or coated with clear protection film nothing or cracking of the material. paper protection covered acrylic hit or miss. white paper placed under or on top so so engraving, thick cardboard under has given me the best results with 2 or three passes. the image is engraved in the underside so that needs to be considered when you engrave. power settings the same as listed in the engrave non-clear acrylic.

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as said to engrave on the front side you need to coat the surface with a removable substance, such as chalk or white board pen. i do agree with @pumich that it is not good representation of the product to show that as an example when it can not be engraved without additional resources & effort. my question is has anyone tried a clear spray paint enamel? it would be easily applied and should provide a good surface to absorb the light.