Saturday, December 31, 2011

Creating PCBs addendum - drilling

Just a quick one to finish up the Creating PCBs series. I've loaded the demo PCB into the CNC machine and set it up to drill the header holes.
Here's the final result:
The area on the right is where I attempted to tin some tracks with solder. I need some new solder wick I think, and some liquid flux.

Some stats on how the drilling was done:
1mm HSS drill bit in a standard mains power drill, mounted in my homemade CNC machine. The power drill nameplate says 2700 rpm max speed. I had it set to max, so the "spindle speed" was somewhere near that.
CNC driven by EMC2 from a IBM Thinkpad G40
G-code generated by pcb-gcode user-language program in Eagle 5.11
Feed speed: 90mm/min.
Drill depth: 2mm
Retract height: 1mm
Dwell: 0.1 seconds

I had to add these commands to the generated gcode output to get it to work correctly:
F90 (set feed rate 90mm/min)
Z-2 R1 P0.1 (set Z depth, retract and dwell, added to first drill line only. Values still apply on subsequent drill movements)

And of course, here's a video of the CNC in action...