Smooth Acrylic Engrave Settings, please help!

[starglazed]

Hello! I’m new here, have had my Pro for about a month!

I work with acrylic (proofgrade and Canal Plastics) and I have been trying to get some smooth engraving that is not too deep.

I have tried raising the lines per inch (450), which helps the smoothness some. I have also been defocusing the laser from .125 to .225. When I try lowering the power to say 80 or 60 to get a more shallow engrave it ends up bumpy, compared to the smoothness I get when I use full power.

Here are some examples:

Are there any other adjustments I can do to make it a shallow smooth engrave?

Thanks for your time!
Katie

[Jules]

LOWER the LPI. Fast speed. If you want clean edges, run a separate edge score afterwards.

[eflyguy]

As you’ve already tried a defocus engrave, have you tried one “normal” pass to get close, then a second defocused pass at a lower dpi?

You can lower the lpi on the first pass as well when you are going to go back over it, so it doesn’t result in a slower overall print time.

Personally, when I’m doing infill like that, I just put in enough paint to pretty much fill the engraved area.

[takitus]

This looks like it might be a case of raster engraving causing variable heights due to not-quite-black areas. I’m guessing it was hand drawn and scanned in somehow?

Have you tried making a vector out of this and using that instead? You’ll need to make sure there aren’t any voids in the areas you want engraved.

Once you get that set, I’d recommend 340lpi with a 1/16-1/8” defocus. Full power at 2k speed should give you a fairly shallow engrave

[rbtdanforth]

I have done such pieces frequently. To get rid of LPI bumpy you need a high LPI, I set the height at 0.3 to 0.5 full power and high speed (1355 LPI , 2500 speed variable …

[starglazed]

Thanks for replying, I am trying to match your settings.
How are you getting those options? Mine doesn’t look the same.

[rbtdanforth]

That only works for rasters. You would still want 1000 and as high in LPI as you can manage. I expect probably 450 or 690. The variable power has 256 power levels, so the larger it is able to spread the results but that is also a raster ability. For acrylic things like grain such as you have to deal with in wood. A height of 0.20 would be better.

[starglazed]

Actually it is a vector graphic already, so I’m not sure why it’s turning out this way.