TinyG2 (ArduinoDue + gShield) FW ver. 89.02
Chilipeppr Eagle Import widget, inflate traces (16 mils): 0.2
Chilipeppr Autolevel widget: probing every 5mm
Cutting traces: V-bit 0.2mm 20deg, depth: 0.1 mm, feedrate 30mm/min
Quiet spindle 12000rpm (PWM)
Holes: 0.8mm and 1.0mm
Board cutout: endmill 1.3mm with steps 0.25mm and 60mm/min feedrate
Eagle generated g-code didn’t have Sxxxx (spindle speed) after first M03, added manually. The initial Z0 was too high feedrate and I cracked the bit at the first try. Moved F30 one line higher in g-code manually. Holes drilled with Z-1.5 which was not enough and I have to drill again with Dremel.
Beautiful looking traces. What kind of machine are you using? Is it ballscrew-based?
Also, you could re-run the drills if you want. The gcode is commented where the drills start. I recommend you just set your Z zero to say 0.2mm lower than you should and then run the code to get those last bits of material out of the holes.
We should add the Sxxxx after the M3 in the gcode.
Yep, this is 3040 with ballscrews. I re-drilled the holes on a CNC and board looks fine now. I did not expect such a beautiful traces by a CNC cut.
I used very conservative feed/plunge rates, but I think it is better to wait longer than crack bits.
It looks like you had to sand the board afterwards? I found with tapered stub endmills I no longer have to sand the board. V-bits always mangled the edges of the copper, but not sure if you really had to sand?
@jlauer Yes, I found three shorted traces and removed them with sandpaper, not the best option I must say. To remove one last ‘short’ I used a v-bit with cracked edge. Next time I will probably try car polishing paste.
Where can I get the endmills you mention?
I reviewed board with a USB microscope and even single trace board outline is close to perfection, except that there are little more copper ‘spikes’ creating shorts. Maybe going a little deeper would help avoiding that, but the cost is the width of the cutting area. Need to experiment more.