Question Questions regarding PCB milling

That was quite an ambitious layout for a first attempt!!

Getting the FR4 flat is, as you found out, critical to getting a proper depth everywhere. I chose to make a vacuum table so that with a good single stage vacuum pump I could easily get an effective pressure of 10lb/sq inch (700g/sq cm).

Milling the table flat is essential in my experience, and the final result is that over a 10x10cm board there is less than a 15micron deviation from level.

On my laptop I stripped out as many unused applications as I could - anything to reduce the chance of Windows screwing things up (which it will do given half a chance)!! Another thing I did was to make sure everything was earthed - in particular I connected the 0V of the control board to the frame metalwork of the Stepcraft (see picture).

I don't know if this made a difference, but it seemed a sensible precaution. The usb connection seems very solid - only had one instance of loss of comms in 5 months.



Peter

Sjömark wrote: Sadly the unccnc crashed at 90%. (Lost connection between PC and CNC.)
I'm using the provided UC100 usb interface and a laptop, Asus I7 8GB.
I guess I will move over to a real hardware parallel port if I get more problems.

In the Windows hardware control settings, under USB Energy Control, there is a setting "The computer can switch off this apparatus to conserve energy" (I don't know the exact wording in English). Make sure this setting is unchecked. This may have been the cause op your lost connection.

Lou

Thank you for all help.

Peter, or any, could you describe the procedure to find the backlash?
I have milled a similar pattern and meassured on it.
I find that 15mm is actually 14,8mm (X axis).
I also made a circle with the radius 29,65mm = diameter 59,3mm
I meassure the circle to aprox 58,5mm.

BR
Terje.