Re: [CAD_CAM_EDM_DRO] milling fine detail in metal

I'm currently working on a small cylinder block in G4 gunmetal (a type of
bronze)- probably a bit larger than the work you are doing. Most of the smaller
features are profiled using 1mm and 1.5mm cutters. I started with a HSS 2
flute slot drill that lasted all of 20 seconds before it broke. After
switching to solid carbide 4 flute, I've not bust another one yet even with
some deep plunge cuts. Search out solide carbide carbide center cutting 4
flute slot drills (end mill in the USA) - IMHO robust and long lasting little
blighters ;-) A jet of air will clear the chips away, flood coolant would be
just as good, essential if you work with aluminium. One advantage of using
carbide, is you can cut dry, just don't use drip feed - the themal shock to
the cutter can cause micro fractures within the carbide. The disadvantage is
the high spindle speeds required for optimum cutting speeds. I max out at some
3500 RPM, so feed speeds have to be cut right down.

Rgards, Paul.

Here's a snip from an earlier thread that might be of interest.

bfp@...
engraving cutters all shapes
http://www.antaresinc.net/EngravPage.html

end mills & ball end mills
metric from .2mm up
http://micro100.com/Metric/index.html

end mills & ball end mills
inch from .005 to .125
(theres bound to be something 'close' to the metric size you want)
http://www.drilltechnology.com/drill/endmill/endmillmenu.html

> I have it working to a accuracy of about 0.1mm. To mill wax 0.5mm
> (0.02inch) broken drill bit works quite well. At this stage however I
> would like to mill brass (or another suitable metal) Ideally I would
> like a milling depth of 0.5mm but I can set the machine up to do it
> in multiple passes.
> Does anyone know if there are bits available of this size to mill
> metal (perferrably without using liquid cooling or forced air)
> I would appreciate any advice on this topic.
> Thanks.