One if the fundamental problems with deep cuts on a laser is that the beam is cone shaped. So as you try to focus deeper and deeper the side walls of the cut above impinge on the cone. If there is enough power to ablate at the fringes of the cone it will cut a V but if not the walls reduce the power at the focus point below.
The GF can only focus over a 0.5" range so I don’t think cutting 25mm deep from one side is realistic.
When I designed some of these in fusion I used toothpick holes for alignment. Little holes that you would slip a toothpick in and snip and sand or slipt it back out once everything is placed and set. Just don’t do holes for the top layer all the rest would be hidden
You can (at least with other lasers). I do 1/4" acrylic all the time using 60W at 95% and 10mm/sec. On the 40W that would have to be about 6mm/sec but still very doable.
If it’s a standalone piece the slope on the cut is indistinguishable. But if you’re going to be edge gluing you need either a gel-based CA or you do 2 passes (faster or lower power) and that tends to make a more straight cut (but never truly straight due to the shape of the beam). I always cut with the focus 1/2 way thru the acrylic vs focusing on the top surface.
Can’t do it with the GF, but other lasers that have the room let you switch to a 3" lens instead of the standard CO2 laser’s 2" lens. That makes for more vertical cuts as well.
Don’t know if you saw this post where I tested the acrylic. I did it with 80/20, figuring it would work from my small tests.
One of the things I am discovering is that when I do my own settings, I tend to make it as minimal as possible. So for a big job it will cut through all the way on 95% of the work, just barely making it through the masking or not even through the masking. Then that leaves some not cut through. When tight tolerances aren’t required, I can blow through it and not worry about a wider kerf.
For my shadow box, the Proofgrade settings in walnut did every cut on every piece just perfectly with an amazingly small kerf.
That’s a good idea. A nice geometry problem to solve. Once again 3D programs assist in this.
It is small at the focal point, maybe 0.2mm, but as it leaves the lens it will be a few mm in diameter, hence the cone. So over a 2" focal length it goes from something like 5mm down to 0.2mm. The shape is actually a bit better than a pure cone as it has an elongated point.
I have done one that was around 20" (500mm or so) which had about 20 something rings. I went upwards half way, then continued back down so the last ring was on plane with the bottom. Looked cool. I’ll try to find a pic.