How to change track width and single side in freerouting


I was able to run free router on a Kicad layout and back annotate the routing back on the pcb. But during auto routing, the track width was chosen to be very thin and routing was done using both sides. I wanted to know the following:

** How to assign track width in auto routing?
** How to select on which layer the routing has to be done. I tried it on a board which had been manually routed (completely) on one layer. But auto router used both sides. Is here a way to tell auto router to use one layer only? Also, how to change the spacing options of auto router ie track/pad to ground plane clearance.

Arvind Gupta

Track width and clearance can be set for each net from PcbNew from the Design Rules -> Design Rules menu, Net Classes Editor tab. Those values are used for both design rule checking and autorouting.

You can set up PcbNew for a single layer board from the Design Rules -> Design Rules menu, Layer Setup tab. That should force the autorouter to try to do a single-sided board. But don’t expect a successful one-sided design for anything non-trivial.

Why are you doing a one-sided board, anyway? Everybody uses at least two layers today. Most board houses have their cheapest offering as two-sided with plated-through holes.


Think you can also set to limit the routing to a single layer within FreeRoute - it is under the 'Parameter … Autoroute" menu. But unless it the routing is really trivial it will probably fail if you force it to one layer (see screenshot of an arduino nano) .

There is another problem with relying on autorouting - if it is trivial it doesn’t need auto routing but if it is difficult the autorouter may still fail and you then haven’t got any experience in routing manually and will find it much harder to see an alternative solution.


Thanks for the above suggestions. They helped alot. I had a few other queries on auto-routing pls:

  1. Once the component placement is done, is it possible to assign separate track widths and clearance values to selected tracks. Presently the free router takes the default values of track width and clearances for all tracks and uses them generically.

  2. Is it possible to insert ground plane through free router. (This is a trivial query but if it can be done, it will be useful for me)

Arvind Gupta