PCB track laying skills

Layout
1

Hi,

Almost finished my latest PCB, and would like opinions on my track laying skills.

I found it very hard to do, but must stress that it’s my fault not Kicad’s. I always try to avoid VIAS, but ended up with more than ever. Also there are VIAS where I’ll connect wires between tracks/pads.

Here is an image showing the results. Does it look reasonable, or poor track laying?

Camerart.

Tracks
Tracks1603×1007 300 KB

2

But still some unconnected nets. I would have moved the big SMD DIL package slightly up and away from the pqfp

3

The layout looks reasonable, however the placement of your pin headers seems a little random,

Vias are not evil, Its just a case of breaking ground planes under signals can cause some weirdness if your in some very electrically noisy environments,

Pretty much if you asked 10 different people to layout a board, each would come back quite differently, My own normal method is “Chunking” Where you group the functional parts into close little groupings, then wire them together, for more complex designs it means you don’t make any compromises about the functional pieces and only need to fight the interconnections.

If this is meant to mount in some kind of enclosure, don’t forget to add some mounting holes.

4

Hi D and R,

Thanks for your appraisal, and good to know it’s not a disgrace:)

If I carried on and connected the unconnected ones, it would be Christmas, so I added VIAS and will WIRE them.

Coincidentally I missed a track off, that needed the SMD DIL moving up a bit, and improved some tracks…

VIAS aren’t evil, but as I make my own boards and not proficient as surface mount, I try to avoid them as much as possible, but seemed to be adding them as if they are free.

Regarding mounting holes! Good idea, but they will be in different enclosures, so I’ll make it up later.

Cheers, Now to PRINT.
C

Done
Done1445×952 295 KB

5

So… sort of a 3rd layer using jumper wires.

With your jumpers, make sure that:

  1. If you are having these manufactured at a board house, you specify that your vias are NOT tented. Otherwise the vias will be covered in soldermask leaving you to scraping the mask off (and potentially out of the via holes themselves).
  2. The via drill holes are a large enough diameter for the gauge wire you plan on using.
6

He is etching/drilling his own boards, so the vias will need “plating” (ie. a wire). Soldermask won’t be an issue. :wink:

7

Sorry, I missed that. Please feel free to ignore me. :sweat_smile:

8

If soldering with an iron it can be a bit easier to solder TQFP etc… if you leave a bit of the trace straight after it leaves the pin, some of the footprints even extend the unmasked area a bit further. It makes it a bit easier to solder it without bridging as there is somewhere for extra solder to go other than between the pins.

9

In general, manual soldering is easier if pads are enlarged in a direction where it permits more contact with the soldering iron’s tip.

Dale

10

Yes that is what I was saying in the 2nd half of my post though not quite so explicitly… I don’t use longer pads though personally as I only assemble the boards once by hand then just have them mass produced. I don’t want parts trying to float around or anything on the extra unmasked area.

If you hand solder parts always the handsoldering specific footprints are great.

11

Hi,
Some interesting thoughts!

As I’m new to Surface mount, I’ve been experimenting with liquid solder. A syringe didn’t work so I either dab a touch of paste on the TQFP traces, making sure there are gaps between racks, then hot air the PICs to the board. The other method is to wick the excess solder of after soldering. I once had a problem where solder had run under the PIC, watch out for too much solder.

Cheers, C.

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