Selecting which side of a board to place a symbol ("part")

Layout Footprints
1

I’m to make a board that is largely SMD components on one side and a ground plane on the other… except there are couple of through hole parts to be installed on the ground plane side. When selecting a symbol to be placed, where can I specify on which side of the board it will appear? Realizing that the footprint will be a mirror image from what it would be if it was on the SMD side.
Perhaps a related issue, but when I started routing traces between the SMD components, the router would not allow traces on the “red” side of the board. There was no conflict to make that necessary, I had already routed most of the “blue” side before that started happening.
Feeling that I have missed something very fundamental here.

KiCAD 9.0.1, Win 10

2

If you want to add a trace you will need to add a via to get from the “blue side” to the “red side”.

3

Add the footprint, then select it, right click, select “Change Side / Flip”. Carry on

4

Apologies, I mis-spoke. I want all of the traces on the blue side. In the course a placing traces, I could not get KiCAD to allow my next blue trace; it instead insisting to run the trace on the red side. The red side is my ground plane.

5

Symbols are for schematics. For the layout the correct term is footprint.

6

“Change Side / Flip” was exactly what I was looking for… for a day and a half now. Thank you.

7

Ah - correct. I’m not very exact in my terminology yet. I’ll get there!

8

Which layer is active when you are adding tracks?
image

9

I’m on the blue side. When I go to place a track, the curser shows a red track and the layer indicator is suddenly red. I hit Esc, and the layer indication returns to blue.

10

Do you have a schematic?

11

Yes - that is where the layout came from.

12

If you are trying to create a track from a SMD footprint that is on the front aka “red side” layer then you will need to add a via to transfer from the red side to the blue side to continue.

Something like this
image

13

This dropdown selects the layer to work on.

image

14

When I opened up the PCB editor, I “assumed” that I was working on the blue side and I was placing components (er, footprints!).on the blue side. My ground plane would be the red side. Is it possible that KiCAD won’t work like that?

15

The status line as well as the pad colour will tell you which side of the board the footprint is placed
image

16

ding ding - we have a winner! Completely resolved I think! Thanks.

17

You’ll need that layer selector also when drawing the board outline on Edge Cuts, and if placing text or drawing graphics on a Silkscreen layer.

18

For clarification:

You do not specify this in the schematic. When footprints are placed on the PCB, they are on the Front (red) by default. As thebigg mentioned, when footprints are selected, and you press f, then they are flipped to the other side of the PCB.

Putting SMT on the front, and the GND plane on the back is the traditional method. It improves the resemblance to what KiCad shows, and what you get when ordering. It’s also (arguably) easier for manufacturing of the PCB.

Also: When you start routing a track from an SMT pad, KiCad automatically switches to the same layer as which the pad is on. Regardless of whether the Front or the Back is currently the active layer. So first do the footprint placement, then route the tracks.

19

Thanks - good mentoring and I appreciate it. I wasn’t paying enough attention to the front/back as I started out.
Ron

20

If it was me making my PCB, I’d place all the smd and tracks and flipped tht on the red side, then, when assembled, mount the PCB upside down.
This would save a lot of messing around.