Working with YAG crystals can be tricky, and the right diamond drill for YAG makes a big difference in hole quality and avoiding micro-cracks. Drill geometry, grit, and coolant all matter.
A good reference for drills designed for photonics applications:
https://ukam.com/diamond-core-drills-tools-for-photonics-industry/
What drill sizes, speeds, and coolant setups have you found work best for clean, precise holes in YAG?
I don’t drill yag but I cut several varieties of yag. The ND yag is a easy type to work with. The CR yag is a little different. It seems to have several extremely hard areas and is definitely harder than ND yag. I confirmed this with the manufacturer. I get my yag directly from the company that grows it and produces laser rods mainly for the medical industry. The CR yag is what they call Ruby yag. It cuts amazing stones if you understand the hardness and sometimes pitting issues on a few facets. The pitting is usually easily fixed by a change of lap direction. The hardness issue is not as easily solved but patience and a gentle touch on the cutting laps and a very good prepolish then 100k on a ceramic lap seems to be the answer. I have not cut enough CTH YAG yet to give an in-depth description. But I intend to in the next few months. What are you making that requires drilling yag?
That’s really useful insight, especially on the CR vs ND behavior. Makes sense why drilling would be even more sensitive with those harder zones. From what I’ve seen, lower RPM with steady coolant and very light feed help reduce micro-cracking, but consistency remains a challenge.
Mostly looking at small precision holes for optics-related work—so surface integrity matters a lot.
Yes optical work is definitely way beyond my area of knowledge. I was experimenting over the last few days trying to find a better cutting option. This doesn’t make sense to me but maybe it will to you. I have a few solid copper laps. I never hardly use them anymore but I charged one with 1200 grit diamond and oil. It cut the cr yag with the extremely hard areas like butter. I was actually shocked. I have 4 1200 laps. 2 steel crystalites and 1 aluminum crystalite along with a 1200 sintered lap. They all cut but they seem to struggle with cutting. The copper charged 1200 cuts like butter. I’m actually having 2 others resurfaced so I can see if they will polish better than anything else I have. I have 11 different polishing laps.