Antarctica
Hot Rolled
- Joined
- Jan 16, 2007
- Location
- Annapolis, Maryland
I have an interest (and a moderate, but not immediate need) to make hemisphere's/lenses out of glass. I've searched through the forums and have found some good info, but not a lot. Both of these threads gave me a good starting point:
http://www.practicalmachinist.com/vb/general/generating-spherical-surfaces-139400/
http://www.practicalmachinist.com/vb/general/internal-hemisphere-138401/
and I picked up the text "Precision Optical Glassworking" by Zschommler mentioned in one, which provides good detail on fly-cutting hemisphere's with a knee mill.
So what I am really after are the tools and techniques for how to machine glass in low quantities. My understanding of the normal "grinding" process is that a tool is made (as in the "Generating Spherical surfaces thread) or a hell of a lot of grinding take place (for a lens that has a small radius of curvature relative to its diameter).
Poking around manufacturers indicates that most are cnc machining the glass to get to the basic shape and then polishing. If I have to make a tool to polish, that acceptable, but I really want to know how to get the glass to its rough shape in a cnc machine. And nto some special glass machining machine - I've seen them and they look like the cats ass, but I need to do this with what I've got. How do I do it with a basic CNC lathe or mill (i.e., the one's I've got).
Most of what I need would be low quantity - 5-20 units. Poking around on the internet brings up info on single point diamond turning, etc. Some corporations involved with specialized glass also list cnc operators in their careers section, so they must be doing it this way.
Am I right or worng - can glass even be worked this way?
Who makes the right diamond tools?
Feed and speed info?
Any good papers or books on the subject?
Absolutely any info would be helpful.
Brent
http://www.practicalmachinist.com/vb/general/generating-spherical-surfaces-139400/
http://www.practicalmachinist.com/vb/general/internal-hemisphere-138401/
and I picked up the text "Precision Optical Glassworking" by Zschommler mentioned in one, which provides good detail on fly-cutting hemisphere's with a knee mill.
So what I am really after are the tools and techniques for how to machine glass in low quantities. My understanding of the normal "grinding" process is that a tool is made (as in the "Generating Spherical surfaces thread) or a hell of a lot of grinding take place (for a lens that has a small radius of curvature relative to its diameter).
Poking around manufacturers indicates that most are cnc machining the glass to get to the basic shape and then polishing. If I have to make a tool to polish, that acceptable, but I really want to know how to get the glass to its rough shape in a cnc machine. And nto some special glass machining machine - I've seen them and they look like the cats ass, but I need to do this with what I've got. How do I do it with a basic CNC lathe or mill (i.e., the one's I've got).
Most of what I need would be low quantity - 5-20 units. Poking around on the internet brings up info on single point diamond turning, etc. Some corporations involved with specialized glass also list cnc operators in their careers section, so they must be doing it this way.
Am I right or worng - can glass even be worked this way?
Who makes the right diamond tools?
Feed and speed info?
Any good papers or books on the subject?
Absolutely any info would be helpful.
Brent