gEDA-user: Galaksija motherboard

[Jeff Webb]

Tomaz Solc wrote:
> Yes. That CircuitCAM software has a feature called "rubout" that will 
> completely remove copper where it's not needed. It's a very time 
> consuming process but people in the lab told me that otherwise it would 
> be very hard to solder components on both sides without shorting 
> something (there's no solder mask).

The CircuitCAM software also has some settings to increase the amount of copper cleared around pads without rubbing out the entire board.  (It simply runs the router around a pad several times with an increasing radius.)  This should take care of most soldering problems.  Of course, if you don't want islands of dead copper on your board, then rubbing out the whole thing is they way to go.  You just use up a lot more router bits that way.

>> If so, why does it look like the clear areas are a diffferent height than
>> the trenches next to the copper tracks?
> 
> The rubout is done using a wider router (2mm I think). I guess that this 
> wider router was positioned a bit higher than the router used for 
> contours (I think the mill they used doesn't have Z-axis positioning).

With the LPKF milling machines I have used, you had to manually adjust the depth of the cut before milling.  It's easy to see how you could end up with a different depth when different router bits are used.

-Jeff