Glass

[DLMACHINE]

Any ideas on milling glass at 3000 rpms on a vertical mill?? Could really use a point in the right direction for tooling.

[hardmill]

PM one of these guys @ this link, i have absolutely no
idea how to cut glass.

http://www.cnczone.com/showthread.php?threadid=357

Let me know how it goes/

PEACE

[cam]

we grind glass for a living here and couple of things to do
diamond tooling 80-150 grit roughing/180 and up for finish
our spindle speeds normally run around 6500 rpm(cnc)
we wax the material to "sacraficial"glass for reducing chips cracking or breakage
need more info let me know

[jahl69]

Then I can put a diamond wheel on my old 4000 rpm hand grinder mounted on a solid frame kicked over at a certian angle to put a spicific sag. in an optic morror??

[ImanCarrot]

I used to grind glass on a 2VS vertical mill. The tools are actualy sintered diamond on a torus on the outside diameter of a deep shank (picture a coring drill but scaled up with sintered diamond at the cutting torus
. Coolant is important otherwise the glass cracks.

Obviously if you tilt the tool one way it will produce convex surfaces and concave the other way. You will need to "smooth" the glass surface after this roughing using (usualy) 3 grades of Aluminium Oxide or similar. Youcan then polish it using the correct grade of pitch and Cerox or Jewelers rouge with water and a lot of time

hehe hope this helps. if you need any more info on optical working ive me a shout

[jolliesconcept]

I am also looking for ways to machine Glass.We are having
CNC 5-axes,vertical milling with 60K RPM.We are trying tp machine our Watch glass crystal using our machine.Pls send me all the precautions and process required.

ALso guide me some diamond tools to get the 3D shape as our watch crystal is not a commonly used flat glass but it consists of a spherical surface with a non symmetric profile.

Also guide me with the tool geometry...

[anonymality]

Originally Posted by jolliesconcept I am also looking for ways to machine Glass.We are having CNC 5-axes,vertical milling with 60K RPM.We are trying tp machine our Watch glass crystal using our machine.Pls send me all the precautions and process required. ALso guide me some diamond tools to get the 3D shape as our watch crystal is not a commonly used flat glass but it consists of a spherical surface with a non symmetric profile. Also guide me with the tool geometry...

Maybe I'm missing some details here but if you need to do a big production of these you may consider a tungsten carbide mould for optical quality finished part right out of the mould.
But if your wish to machine these parts you might have to make a lot of experiments or consider having them made by a specialized optical glass shop.
If you REALLY want to machine your parts then you will probably need to make a custom vacuum fixture and get your hands on some metal bonded diamond tooling (80-180 grit for roughing, 220-400 grit for "flat" finishing). For a clear finish seach for "glass buffing disc" on google. These buffing discs wear very quickly and they need to be changed often"0.2mm rad. wear for +/- 1m edje. Cooling your part and tools with lots of freshwater is essential especially when polishing.

Hope this helped you... or anyone else.