Hi Dan,
How does this etching work? How does it produce the required shade? Doesn't it just melt the acrylic?
The laser doesn't actually melt the acrylic, the focal point is far too hot for that, it vaporizes it. There is no residue or melted stuff, and the vapor just gets sucked out by my extraction system.
The image itself is generated from a raster scan with the laser being switched on and off as necessary (bit like an inkjet printer I suppose but just one line at a time). This is bit of a painstaking process for my machine because the mass of the combined X and Z axis is such that my maximum, reliable G1 feedrate is only 4000 mm / min. and with a line increment of 0.015 mm it took some time to complete.
Think you can do 3D shapes in a glass cube like those sold in souvenir shops? That would be lovely. But then you need to focus the laser at different heights - can you do this?
No can't do this. The wavelength of my laser is 10.6 microns and that treats almost all stuff that we see as being transparent as opaque and dumps its energy on the surface. (Different wavelength lasers each see materials differently).
Hope this answers your questions,
Tweakie.