I purchased the Glowforge to engrave on powder coated aluminum and anodized aluminum.
I’m happy with the detail of the first test engravings, but I can’t quite seem to get it to be that nice bright aluminum color that some of you are getting. The steering wheel plate is the powder coated plate and the mousepad is anodized aluminum. The powder coat is much thicker than the anodize.
I used acetone and that did seem to help a bit. One thing I’m wondering is if I take more time to prep the aluminum before anodizing and get a perfectly smooth finish, that the engraving will look better.
Anodized aluminum can vary a lot, as you seem to be aware. But I wonder why you’re going to slowly? Every single anodized aluminum item I’ve done I’ve done at 1000/100. I wonder if, by going so slowly, you’re possibly scorching the coating or the aluminum, making it darker. I’d recommend just doing some basic testing… A small shape at 1000/100/450, 900/100/450, 800/100/450, and so on. Then, without taking out your test material, you can take a look and see your result. If you want to, you can then do a 2nd pass on the whole thing and see your results there.
Anodized aluminum is one of the only materials I’ve tried that looks better at higher LPI. It removes any possible trace of overlap or anything caused by even the tracest amount of variation in image, power or anodization.
SOLVED! Newbie mistake I had the power down to 10% thinking it was 100%
Middle is 10% 400 speed 2 passes, bottom is 3 passes
Top is 400 speed, max power, 2 passes. Then used Acetone and a rag to clean it up.
The big thing about getting that finish was sanding the aluminum to 2000 grit and then using a buffing wheel to get a mirror finish on the aluminum. I then powder coated it and running it at full power gave an AMAZING engraving! Very happy
I’ve never tried that, so I can’t argue that. I can however vouch for the difference between low and high DPI. I’ve done quite a lot of anodized stuff, but the items are relatively so small that length of time to engrave has never been an issue…and one small step less than your idea. Maybe sometime I’ll try your idea, though. Always fun to test things.
Speaking of defocusing…I’m very interested in that concept…but, mostly for acrylic. I’ve read a little about it here on the forum, but there’s really not a lot to read. My question now is…how does one know how much to defocus? …and in which direction? Or does direction matter?
The other day I read .25" defocus to .433 …then today I read a different one, .125 to .03. I don’t see any rhyme nor reason to it, but if there is I sure would appreciate hearing what it is. And these numbers were both with acrylic.
The beam is an hourglass with the focus in the middle.
If the focal point is above the material it’s on the “bottom” of the hourglass and is progressively getting wider, and therefore less intense.
If the opposite, then the beam is still getting more intense as it approaches the focal point.
It seems to me that as you remove material therefore it’ll be increasing or decreasing the intensity as the engrave gets deeper.
This effect might be completely negligible in all materials, and certainly is when engraving something where no material is removed (aluminum), but (in theory) the two setting could have different final effects in many materials where the engrave has some depth.
My gut says the difference will be undetectable but the two settings are definitely not the same in terms of what’s happening with the laser.
For Acrylic I defocus to the max I can enter in the field (.5" iirc) in the operation - I’m overriding the material setting. The material setting stays as the true thickness if the material (generally 1/8 or 1/4") so I can get a good bed image and the cut focal length will be correct.
I did a defocusing test yesterday…on medium PG clear acrylic, using both the ‘above’ and below settings. The .5 setting gave me the best outcome, however…the engraved parts looked sort of yellow compared to what engraved acrylic normally looks like…the frosty white. I did a bit of cleaning on it which improve it, but I’d like to know why that happened?