Are you able to mill PCB's with the required accuracy to do some of the surface mount parts being discussed on other threads that may have a mere 0.25mm gap between the pads? I'd like to have a go at this, but the required accuracy seems daunting. I'm guessing ballscrews would be needed,but I'm not sure whether or not even they would have too much backlash. Plus, runout on the spindle is going to be a factor as well.
I purchased some 0.1mm 20 degree etching points and also some 0.2mm 30 degree etching points. I think my drillpress probably has too much runout, but maybe if mounted in a dremel (using a dremel press), it might work without too much runout(?). I don't presently have a mill, but I do have the Proxxon XY table (KT70) that I could maybe use for running some quick tests to see whether or not there's a snowball's chance of it working.
[Update: I went ahead and purchased the Dremel "workstation" today (really a Dremel press), so at least I'll get a sense from that what the runout on a dremel is like. Perhaps I can manually cut a solder mask out of soda can aluminum using the dremel press to provide an on/off z-axis and the Proxon xy table to orientate the metal sheet for cutting.
It looks as though 0.1mm is the smallest etching point available. I've read that 10 degree 0.1mm are mostly good at producing nasty shrapnel, which is why I went with 20 degree 0.1mm.
It occurs to me that the screws on most CNC machines may be too coarse for supporting this type of work. I get the impression that 5mm of travel per turn is what's common, but that seems like maybe too coarse for the level of accuracy required to etch the traces for fine pitched SMD parts. So, I'm just wondering aloud here as to whether finer threads on a regular screw might actually outperform a 1605 ballscrew in terms of accurate positioning?
Proxxon has come out with their own CNC machine that, unfortunately, is super expensive. What's interesting is that Proxxon claims that for really high accuracy CNC milling you also need brakes on the stepper motors to lock them down while doing cuts. I guess that's yet another way to address the backlash issue. There are inexpensive ($50) adapter kits, though, which allow the low-end ($400) Proxxon mill to be outfitted with stepper motors, and if it turns out to be accurate enough I may go that route. Perhaps adding some stepper brakes and also some precise linear encoders for positional feedback would do the job. That said, I'd really prefer to just buy something off the shelf, if it were affordable that is.]