PCB bits on sapphire
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Nixie

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The carbide PCB drill bits are tungsten carbide, right? I need to drill holes in a sapphire wafer, and I'm wondering if these bits are easy to sharpen, since sapphire is almost as hard as the carbide, and so for each hole through the 0.8 mm wafer, I'll loose a decent fraction of that from the carbide bit.

The other question is how to cut the wafer. I can't find any diamonds around here, artificial or not (the sapphire I got as free samples from an optics manufacturer). Someone told me to etch with hot molten lye, but that won't make a clear cut and will take forever.

And yes, this is sound related, as I need it for insulator in the plasma MHCD electrodes, for my Plasmatronic derivative.
 
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Heady

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If my material science is correct after all the years, the only practical thing to cut sapphire with, is a diamond bit. Even then, it won't be easy.
 
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Voodoochile

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I don't think carbide will do it either. I'd be worried about overheating and cracking, even with a coolant jet running on the tip.

You probably should locate a diamond-tipped bit or even a burr, and run it as slowly as possible with constant coolant to flush away the debris and keep things from getting too hot.
 
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Nixie

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Damn. Maybe I'll be able to find a jeweller to do it for me...
 
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ble0t

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I'd agree with Heady...my father is a dentist, and you'd be surprised what those dental drills can do (and the amount of drill bits a dentist usually has). I guess the only issue would be convincing a dentist to do it for you
 
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Nixie

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Actually, sapphire is (rarely) used for artificial teeth. It's after all alumina and thus pretty inert. I'll ask my dentist if he can source me some bits.
 
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