Engraving on anodized aluminum

[eflyguy]

Don’t need specific settings, I have those, I’ve used this material a fair amount.

I’m looking for ideas on how best to engrave the likeness of a bank-note (it’s not genuine currency, they are images used to promote the financial plight of many of the Lakota tribe, and a friend of mine is heavily involved in that.)

So I have a stash of black anodized aluminum “business cards”, so obviously a direct engrave would result in a “negative” image. My thought is to just create an inverse image, and engrave that. I have plenty of material to test on, but figured I’d ask here if anyone had done anything similar and could share their results?

[eflyguy]

This is the goal. As the cards are quite small, I am worried I might lose the detail when reverse-engraving.

[evansd2]

I did the great wave once and found that fine details get lost. I have it around here somewhere and will upload a pic in a bit.

I did have good luck engraving large currency on wood though.

Electricity as the Dominant Force in the World

Before we begin: Currency Image Use – Reproducing Color Illustrations of U.S. Currency Federal law permits color illustrations of U.S. currency only under the following conditions: the illustration is of a size less than three-fourths or more than one and one-half, in linear dimension, of each part of the item illustrated; the illustration is one-sided; and all negatives, plates, positives, digitized storage medium, graphic files, magnetic medium, optical storage devices and any other…

[eflyguy]

I have done detailed engraves many times, but these cards are 3.4" wide and the text is quite intricate.

I have enough material to play with, was just looking for experience in this kind of stuff.

[evansd2]

Here you go:

[eflyguy]

Was that solid blue anodized and you engraved away most of it?

[evansd2]

Purple, but yeah.

Here’s the SVG:

[evansd2]

You can sort of see some vertical banding in the middle. I assume this is rough machining of the aluminum under the anodization, though I guess it could be some sort of physical moire from the laser pulses or motion control. I suspect material first though. I should go look at it with a microscope to confirm.

I kept the job in my dash apparently, these are the settings:

[eflyguy]

I have printed that on frosted acrylic, and built a box to back-light with a pale blue LED mix. It runs for week on a small USB power brick. The dark areas were filled with a light teal acrylic, thru the engraving on the masking. It was about 6" or so wide. I never took a pic before I gave it away to the sushi place I would go to often. When my daughter gets back from her stint in Hawaii, I’ll have her buy me dinner there and try to get a pic of it, behind the bar.

[deirdrebeth]

I honestly think you’ll be surprised at how much detail you do retain - I’d go high LPI though, at minimum the 340, and if the time won’t kill it for you, up into the 1355.

[eflyguy]

Thx. There’s no urgency so a high LPI will be perfectly fine. What was posted above is similar to the settings I already use for anodized Alu., so I’ll probably just bump up the LPI and speed it up to see what I get.

[evansd2]

Seconded, previously.

Aluminum dog tags

One quick note: I’ve since worked on settings a bit, lpi seems to matter a lot more than I would have thought. I was doing 340 but have since upped it to 600+ and the result is much better. Aluminum engraves so crisply that it was easy to see the lines at 340, 600+ gives a much smoother edge. I fooled with doing 340 engraving but then running a score of the same path to define the edges and got great results, but my specific path here had a few issues with open nodes and it was not cool. If I…