View Full Version : Another "how do I - glass" question

Paul Williams from Nunavut
10-30-2012, 12:43 AM
I'm still learning to do surface glass engraving, but I was wondering (for future use): with the equipment I have is it possible to engrave inside a block of glass/crystal/acrylic? My laser is a 30 watt Epilog Zing, with CorelDraw graphics suite X5. How different is it from surface engraving? Thanks

john banks
10-30-2012, 6:37 AM
With a 10.6um CO2 laser I believe you will find that the absorbtion of this wavelength will mean you have difficulty altering the subsurface layers without interrupting the surface.

We tried to laser silver nanoparticles in glass and we did indeed change the appearance in the lasered areas from transparent to silver, but with the wavelength we were using I believe it was caused by the heat affected zone from excessive power at the wrong wavelength at the expense of microfractures on the glass surface which ruined the scratch resistance as the silver nanoparticle layer was exposed rather than being subsurface. When we used wavelengths from UV to near IR (so up to about a tenth of the wavelength of CO2) we could use 2% of the power whilst going much faster and not damage the surface, giving the effect we desired. Some people on here do glass work with shorter wavelengths and may post, but most find that all they can do with CO2 is microfracture the surface.

Michael Hunter
10-30-2012, 6:48 AM
The CO2 laser in your Epilog heats and acts on the surface of the glass as the far infra-red energy cannot normally penetrate into the glass itself.

The lasers used for marking inside glass blocks operate at a different wavelength (near infra-red I think) and have different optics (or even dual beams) in order to focus deep inside the glass block.
The software to drive these lasers is different too as full 3D capability is needed which Corel does not have.

The proper machines are very expensive and the value of the output has dropped since every trinket and souvenir shop has these blocks at low prices.

Paul Williams from Nunavut
10-30-2012, 9:24 AM
Thanks, guys. Just a thought. Appreciate the responses.