How can i Set a rule that no routing should be done at the back side of the PCB?

how can i Set a rule that no routing should be done at the back side of the PCB?

i am trying to routh my first project " led with resistor" in auto routh mode in freeRouting , but it routh on both front and back layers , how can i make it routh all in the front copper layer only?

As far as I know there is no way to communicate to freerouter to route other than in sets of two layers.

Also:
Lots of beginners expect an “autorouter” to be some kind of magical thing that does all the PCB layout for you. It is not. They can be a useful tool for some PCB’s, but they can never route a PCB properly if the footprint placement is not chosen carefully, and you only learn good footprint placement by manually routing PCB’s to get some hands-on experience. Finding the right footprint layout can be more time consuming than routing of the tracks itself.

In my experience autorouters just made a big mess of things and got a PCB “routed” for 95% in a few minutes (that was 20+ years ago, after that I just never used an autorouter) and then leave no possibility to route the last 5% and fixing it takes more time than deleting everything and routing the board manually in the first place.

Instead, my advise is to get acquainted with the interactive router in KiCad first. It has some quite nice features. For example it can push tracks and via’s aside to make room to squeeze another track in between.

The auto router usually also does not know anything about concepts such as GND planes, differential pairs and length matching.

I have also found a few mistakes in the schematic while manually routing a PCB. Looking at your work from this different perspective does help to find some mistakes. I also find manual PCB quite a fun puzzle to do. Much better than laying boring pieces of colored cardboard on a table.

3 Likes

Put a keepout zone on the back.

But I wonder why you need an autorouter for a “LED resistor” circuit which should be simple. Are you actually trying to make a one copper layer PCB at home?

1 Like

paulvdh speaks the truth regarding autorouters…

At first I thought they were an “essential” tool, but after spending more hours cleaning up DRC errors (and fixing some routing that was just plain [censored]) than carefully laying out the parts and trying for an X / Y scheme (one side has all the traces in the X plane, the other all in the Y plane), autorouters are just bleh. KiCAD has a good manual routing tool that works just fine once you get the hang of it!