Putting components on both sides of the PCB

[Joao_Duarte]

Hello there!

I’m designing a 1 layer PCB and I have all my components as through holes. I’d like to put some components on one side of the PCB and others on the other side to decrease space. Knowing that, is there a way to put the components in the PCB Editor so it shows that intention? All I get is the red from the overlapping.

Note: This is my first time designing a PCB

Thanks in advance!

[gmc]

Press F to flip the component to the other side of the PCB

[3Dogs]

Note that making an actual 1-layer PCB (without plated-through holes) is probably a mistake these days, unless you have an extremely good and well-considered reason for doing it.

[paulvdh]

Single layer PCB’s are indeed becoming rarer, but there is at least one good reason and another plausible reason for it. It’s used a lot in mass produced FR2, and also for home etching (which can give you a result in hours, instead of days).

[Joao_Duarte]

There is a reason I’m making a 1-layer PCB, yes. I have a PCB assembler in my university which can do 2-layer PCBs instead of 1 but, from what I’ve been told, it’s kind of hard to do so because you have to make sure you align it just right…

[BlackCoffee]

It’s true that paying attention is important for alignment.

To help Alignment of Top/Btm, some options are:

• Use a Guide-Pin
• Use a Fiducial
• Use a Hole - either a THT or NPTH or Edge-Cut-Layer hole
(the three items in lower-left corner)

Quick-dumb example (not a real circuit)

[paulvdh]

My suggestion / idea for DIY etching of double sided PCB’s:

1. Draw something on an unused layer (alignment cross, text, some footprint, whatever) outside of the Edge.Cuts.
2. When you print the foils for lighting, make sure you also print that layer “on all file outputs” (Option during Gerber creation).
3. Also put some readable text on each of the copper layers, outside of Edge.Cuts. (To easily determine mirror image of the transparent output.
4. Mirror one of the layers during printing. The goal is that the ink is on the side directly towards the copper for both Front and Back. This gives the highest contrast for edges during etching.
5. Use scissors to cut out your masks, but leave the “extra’s” on it.
6. Use tape to fixate one foil to your PCB.
7. Place it on a mirror with the bare copper side up.
8. Put the other foil on top.
9. Align the foil by looking straight downward. Move you head so one eye is aligned in the mirror with the alignment mark, then shift the other layer so it also aligns. The mirror trick ensures there is no parallax error due to the thickness of the PCB.
10. Do the same with an alignment mark in the opposite corner of the PCB.
11. Use tape to fixate the other transparent.
12. Cut off excess transparent sheet, or light both sides as it is.

[3Dogs]

Back in PCB pre-history, when I used to etch my own double-sided boards, I used to align the front and back films before attaching one to the bare board. I would tape them together in alignment, and then slide the board in-between them. As long as the pad dimensions were reasonable, this used to allow perfectly usable alignment. But, it still required soldering wire-wrap wire through all the vias, so they were to be avoided when possible.

[paulvdh]

If you first align the films together, then how do you account for the PCB thickness when you slide the board in between?
Having a transparent plastic sheet (or two) with the thickness of the PCB would also be a nice alignment tool. You can than tape both films as a “book” to a thin strip of the stuff, and use a bigger transparent sheet in the place of the PCB to verify the alignment.

[3Dogs]

You just center the board so that the taped edge is in the middle of the thickness of the board.
But, it turns out that it’s really not that critical. I always tried to avoid using tiny vias anyway, since they became impossible to drill without breaking the carbide bits.