Plating PCBs

[Electronics4you]

Hi there

What is the easiest way of through hole plating a double sided PCB - and cheapest?

I need to plate some double sided PCB's within a short time. Is it possible to have a fully operating plating system ready that fast?

 

[dknguyen]

I don't think easy and cheap go hand-in-hand...and my common sense tells me it's not possible to have a fully operating system up that fast, and there is going to be lots of problems.

I have heard of people running melted solder with an iron over all the traces on their PCB though to get the same effect.

I haven't heard of anyone trying to plate their own PCBs...if you really want quality like that it's probably better to just get the whole PCB from a boardhouse in the first place.

 

[Electronics4you]

The problem is, that the circuit is hard to route. I have tried manually and with the autorouter, but it still makes 20-30 unrouted connections. Using jumper wires would just be a mess, so I tried the double sided. The problem about that is, that vias may not be places in component holes. It's hard to solder under a DIP socket.

 

[dknguyen]

Oh, I see what you are trying to do. You are trying to plate through-holes to make vias right? Not apply a tin plating to your traces. What's wrong with just sticking a separate through hole pin in the via and soldering on both sides?

 

[evandude]

Read these pages for information:
https://www.thinktink.com/stack/volumes/volvi/condink.htm


I'm not going to say it's absolutely impossible, but for all practical purposes, plated through holes are way beyond being feasible for hobbyists - and even if you could pull it off, it would almost certainly be prohibitively expensive for small board quantities. In other words, you might as well forget about it.

Place your vias in open areas and solder wire jumpers through them, or if you want to place them on IC pins, use machined-pin DIP sockets which usually have 1-2mm of exposed metal on each pin above the surface, enough to solder to if you're careful.

Believe me, spending an extra hour or two carefully reworking your layout is going to be a LOT easier than trying to do plated through-holes at home.

 

[Electronics4you]

Maybe just because it's a hard job to do 200 vias both in software and afterwards. But it's the cheapest way, and the through hole proces might also be a bit to much compared to my status as hobby electro engineer

 

[dknguyen]

THen you might as well get a board house to make the board, no?

 

[evandude]

Yeah, if you're dealing with a board with hundreds of vias then it would probably be worth your while to get it made professionally anyway.

 

[Electronics4you]

Thanks for your sincerity...

 

[picasm]

It's hard to solder under a DIP socket.

It is possible with care to make double sided pcbs with vias.

First, solder small lengths of wire for all the non-component pad vias (may take some time!)
For vias in DIP sockets, fit the socket so that there is a very small gap under the socket for access to solder the top side and ensure that the pins just protrude enough to solder them on the underside.
Using turned-pin sockets makes it easier to solder the pins on the top side.

Use a very fine tipped soldering iron to avoid melting the sockets.

Test all connections for continuity and check that there are no shorts to adjacent pads or tracks!

Also leave gaps underneath any large components such as electrolytic capacitors that have to be soldered on both sides.

It is not easy to do, but allows you to make and test small prototype boards without having to wait for them to be made for you commercially.

 

[hjames]

This falls into the *definitely not cheap* category
**broken link removed**

The problem is that anything that is active enough to plate holes is also active enough to turn an etched PCB into a single conductive sheet. I think methods either plate the holes before everything is etched, or you end up doing what the LPKF guys do and applying some protective film while filling the vias.

I think I've seen a board where the via's were made of conductive plastic or something wedged into a hole. It didn't seem solderable, but you could make sure all your pads are on the solderside... Maybe some conductive epoxy might do something...
But then this would fall into the "not easy" category...

 

[Dean Huster]

Using IC sockets is usually pointless (unless everything you make never works first time) and is truly inane on a double-sided board. The down-side of IC sockets: add expense; add construction time; add board height; add more stray capacitance and inductance; just another 8/14/16/18/24 possibilities for an intermittent; difficult to solder pins on the component side of the board. The up side? You can easily remove and replace an IC.

No sockets makes it easy to solder the upper and lower pads on a pin. IC removal? Desoldering really isn't that difficult.

Sockets are necessary for some IC types (3,000,000-pin µPs) and may be warranted for things like firmware (ROMs and EPROMs) that may need to be changed periodically or for pricey ICs.

Dean