[cncron]

Anybody have any knowledge or tips about using diamond edged cutters to achieve smooth polished finish when cutting optical parts like acrylic custom lenses. I keep hearing this can be done but our experience shows a "better" finish but not one that can be used without hand polishing.

[tc26]

I use diamond cutters to mill glass on a cnc (HAAS). Anything that requires an optical finish is polished on polishing machines.
I am open to suggestions, if there are any.

[warrenb]

Anybody have any knowledge or tips about using diamond edged cutters to achieve smooth polished finish when cutting optical parts like acrylic custom lenses. I keep hearing this can be done but our experience shows a "better" finish but not one that can be used without hand polishing.

There are 3 edged cutters I use from Onsrud that leave an excellent finish on cutting acrylic. There are a couple ways to get a nice polish on the cut edges. One is buffing and the other is use a hydrogen oxygen flame from a jewelers torch (available at harbor freight) and flame polish the edges. It's tricky but you'll get the hang of it. If they edges are rough you'll have to sand it first. If you are face milling acrylic you'll just have to get the best you can with your endmills, sand, and buff / flame polish. I don't think diamond bits are the way to go with acrylic. Acrylic will just load up the cutter and melt the acrylic.

[ImanCarrot]

Not unless you use Single Point Diamond Turning like wot I do.

You need:

1) A diamond turning lathe, vibration isolated and temeprature controlled with air bearing spindle and slideways (optical encoders for linear positioning)
2) MONOCRYSTALINE gem quality diamonds (see Contour Fine Tooling)
3) For Acrylic- zero degree top rake and 15 deg front clearance on the tool.
4) CAST acrylic (not extruded).
5) Correct depth of cuts and feedrates.
6) Spray coolant optional. personaly I just use air.

Here's some I made earlier (no post polishing, straight off the lathe)

[Edit] Oh, these tools cost about 300 to 700 quid each depending on spec. If you use it on a normal machine you WILL wreck the tool. If you set the tool above part centre or past centre you WILL wreck the tool. If you touch the diamond cutting edge you WILL wreck the tool. Sometimes they can be resharpened at about 30 quid each and 3 week lead time.[/Edit]

If you want more info lemme know.