I’m sure you will enjoy the increased Z, Nice work Jon.
Glass isn’t a material I have explored to any extent. But under magnification, I have noted the power deposited results in a very localized thermal shock, micro-fracturing it to a certain depth in a defined area. I also noticed the pieces can be easily picked out.
Between power/speed, and surface coating, I would be compelled to explore, seeking to minimize the size/depth of the fracture, and compare that result.
Introduce multiple passes and maybe you could dial it in to confine the effect to the very surface with fracturing so small it was homogenous.
The ability to deposit 40w in a .008 area accurately opens a rabbit hole that just keeps going.
The limited Z is a big restriction, but yours no more.
Nice! How do you account for the change in focus height as it goes across a curved surface?
DO tell! Is this increased Z something beyond removing the crumb tray?
I think they probably cut the bottom out of the machine allowing for more Z than normal.
there is a ‘window’ of burn where the lens will auto adjust – I am still learning that area.
As I’m sure you know, the classic way of characterizing that zone is to engrave a rectangular grid of filled circles to check both focus and distortion across the curved surface. Good luck!
Before buying my GF, I used a Rabbit laser at a local maker space. It had an integrated rotary device that made engraving glasses and bottles relatively easy. That’s where I learned to use dish soap and/or wet paper towels to reduce spalling. I have to admit that’s the one feature I’ve always wished the GF had, but I knew that going in, so no complaints.
I’ve never messed with glass, but the people I know that do recommend the following:
Make your design 70% black
Engrave with ordered dithering - pattern in the Glowforge app should work. To dither, you’ll need to convert the text to a raster.
The 70% black and ordered dither pattern separate out and distance the lasers firing pattern so that it doesn’t get blasted as hard in such a small area. Gives it more of a clean, sandblasted look.
They also generally recommend covering the surface of the glass with a wet paper towel.
When I started doing glass recently I got the best results from 2 full Pro power passes and a vector engrave. This made most of the design flake off, leaving a nice even impression.
If there were any parts that didn’t want to flake off I could scrape them out with a dental pick. I would try that on your test bottle. You may be able to clear those white spots.
Oh, I gotta try this, thanks for mentioning it! I tried a few things but was unable to get the frosty sandblasted look.
Welcome to the forum.
In all fairness that is a completely different thread that a new member might not have seen yet.
Thank you for providing them the link, but you come across as yelling at new comers. Not the most friendly introduction.
Welcome to the forum @hawesg ! There is a lot of great information here.
Did you cut a hole in the bottom of your machine? Looks very nice.
I understand. I didn’t think that is what you meant.
I was simply letting you know how it came across, and I didn’t expect that was how you meant it. But someone new who doesn’t know you as well could have been offended.