Wife requested a holiday ornament commemorating our pending addition to the family. I decided to try and make a two piece acrylic design with engraved image of the 20week sonogram on the front.
Had a lot of trouble getting the right settings and image quality for engraving anything good on acrylic. Found the default material settings for acrylic engrave to be awful with grayscale images. I ended up doing several tests with different settings and different image values.
Eventually I settled on inverted image (Black features, white background) and power-varying engrave with Speed = 200 and Power = 25. I also defocused the cut from .125 to .15 based on some comments from other posts to reduce the presence of lines. I think I used 450 lpi setting.
Based on test cut I increased the inner piece size from 2" to 2.01" to deal with kerf and create a good friction fit between the two pieces.
The outer green ring was easiest of all. Default light-engrave settings worked fine for vector art and the cut dimensions were accurate.
Fitted the two pieces together and used a touch of glue to keep them in place. Pretty happy with the final product and hope these methods help others looking to do similar projects.
Used Inkscape, Gimp for design and free online vector art for the ivy effect.
Transparent green acrylic came from Thingiverse.
One thing I forgot to mention. As discussed elsewhere on the forum you definitely want to remove the protective paper when engraving acrylic. Otherwise its just a mess.
Depends on the masking and what you’re doing with the design. Plastic masking is a definite rip-it-off before lasering as it will just melt. But, paper masking can be useful if left - e.g. when you want to paint afterwards. It can be an issue (not just with acrylic) if you are doing low power engraves because the GF can burn away the paper but leave the adhesive with low powers. In that case you may want to take it off. Also, with paper masking I almost always leave it on the backside to prevent flashback and scratches.
I have only done a few engraves on acrylic, but I’ve found the default settings to work quite well with pencil drawings. I don’t image that is an option for sonograms. For everything else, yeah you need to do some work on the image (or presumably the settings.)
A friend of mine from my early online gaming days worked on a bunch of movies. It is so interesting when you come across a guy that did the smoke on the Balrog’s whip.
I did some frame animation with one of those cameras too. Though I didn’t stay in the biz like you.
Chris
material settings for acrylic engrave to be awful with grayscale images. I ended up doing several tests with different settings and different image values.
