I have a couple question for you, I am new to pcb milling. I hope you can share with me your experience.
1)how do you derive at your feedrate? Is there a calculator you use or link you use?
2) Is there a difference between using 0.01 vs 0.0039 Precise Bits EM2E8 EM3E8 Etching Bits in terms of quality?
3) If I use the 0.0039, do you think it will effect the isolation performance of the board because the trace are so small?
4)Do you use auto leveling in your workflow?
scott216 wrote:I'm really happy with these tapered isolation bits, I'm haven't broken one yet! I've got the speed up to 26 IPM with my Dewalt DW660 going 30,000 RPM. I'm running dry without WD40 and the results are pretty good. I do clean up the edges with a little 400 grit wet-dry sandpaper and mineral spirits.scott216 wrote:By far the best bit I've used for making PCBs is the PreciseBits.com PCB Traces-isolation Bits EM3E8-0100-25V. You can get the same bit from soigeneris.com, P/N C5 - PB-EM3E8-0100-25V
I've made over a dozen PCBs and haven't broken a bit yet. Previously with a 0.0118" 2-flute micro carbide mill like this one I'd be lucky to get 3 boards. And that's at 5 IPM. With the Isolation bit, I'm going 18 IPM (@ 30k RPM) and I might be able to go a lot higher. One guy posted he's going 40 IPM a @ 40k RPM. And the edge finish with these bits is great, I don't need to sand the board. I do use a lot of WE40 and have yet to try doing it dry.
I use Cadsoft Eagle with pcb-gcode script to generate the gcode. My bit diameter is set to 0.015", which is a little larger then the actual bit, but I do have some run-out in my spindle. Some of my other pcb-gcode setting are:
Singly Pass - unchecked