Removing char on laser cut acrylic

I’m wondering if anyone has a good solution for removing the dark char around the edges of laser cut acrylic. Even though I mask both sides of the acrylic before cutting, I still get some unsightly burn marks around the edges. I’m specifically interested in how to get rid of the char on white acrylic. Perhaps soaking in a bleach solution? Let me know if you have any ideas. Thanks!

Can you show me what type of charring you are talking about? I cut white acrylic all day long and have no charring what so ever. Also please list type of laser, power of tube and settings you are using as this might be the culprit.

Acrylic/plexiglas/perspex does not laser-char.
Polycarbonate or Lexan does.
Maybe your mask is charring.

Here are some pictures that show the char; it’s not super noticeable, but it’s the brown tinge on the inner cuts. The outer edges seem to be fine for the most part…once in a while it might get a small black scorch mark where the masking tape might have had an air bubble in it. I purchase my acrylic from an acrylic manufacturer, so I’m quite confident that the material is indeed acrylic.

I’m using an epilogue 36EXT 60W laser to cut 1/8" acrylic. I’m using relatively high settings to cut a very intricate vector pattern (speed 15, power 100, dpi 5000). The masking material that I use is a product called “R-tape” that I also purchase from the acrylic manufacturer.

Let me know if you have any suggestions, I appreciate your feedback!

Here are some recommendations from one of our acrylic suppliers that may have some details that help:

· Engrave @ 40 power / 90 speed / 400 DPI Cut @ 30 power / 15 speed / 1000 hz.

Please note these are intended as ‘a starting point’ and adjustments in 5% increments may be needed to achieve optimal results.

· Bottom Up Engraving - Change the orientation of your laser to begin engraving from the

bottom of the material upwards. This simple process will minimize the amount of residue
being exhausted over previously engraved material which can re-deposit on the warm
core and make clean up difficult. You can change the orientation of your laser to bottom
up engraving from the advanced tab in your print driver.

· PPI – Lowering the number of pulse firings per inch, particularly when engraving larger

text or objects, will help keep the material cooler minimizing warp tendencies. Setting
your PPI at 400 for photo engraving helps to minimize the ‘banding effect’ often
experienced with this fabrication process.

· Vector Cutting – When your application will permit, they recommend leaving the

protective masking in place when performing vector cuts. This will minimize burn residue
and clean up efforts. Ensure laser is properly focused to ensure clean, smooth cuts.
Note: PPI’s over 400 when used in vector cutting are likely to cause of tacky edges.

I have also read that the paper protective masking used on some acrylic to protect the surface contains paraffin which can cause charring. It sounds like you are using a different masking material. Are you cutting on top of a honeycomb grid or directly on the bed of the laser?

i just joined this site so i know im a bit late to this thread but rubbing alcohol works well.