Homebrew PCBs

4 layer boards require a really elaborate process involving very
sophisticated laser drills, and a very laborious plating-through process.
It's always automated on bajillion dollar machines.

I've heard of some adventurous hobbyists playing with they're own 4 layer
solutions, but they can't get close to the pitch that the fancy-pants
machines are doing.

I'd LOVE to find one of those fancy machines in a liquidation or surplus
sale. I wouldn't care that it would take up half my garage. rofl.


Oh, and by the way, the terms FR-4 and CEM refer to the substrate that the
boards are made of, and not how many sides are clad with copper. FR-4 is a
UL flame retardant specification, and will usually refer to a board that is
Epoxy Resin bonded fiberglass. CEM boards are often a Synthetic Resin bonded
paper. So be careful when choosing your boards, and don't just assume that
all FR-4 Boards are double clad.

Peace!
-Mike

On Wed, Apr 22, 2009 at 6:35 PM, roycepipkins <royce.pipkins@...>wrote:

>
>
> When you do four layers, how do you connect to the internal layers?
>
> Regards,
> Royce
>
>
> --- In Homebrew_PCBs@yahoogroups.com <Homebrew_PCBs%40yahoogroups.com>, DJ
> Delorie <dj@...> wrote:
> >
> >
> > My stock includes 0.008 and 0.016 thick SS clad. I have some 0.032
> > DS. What I normally do is mask and etch the two (or four) sides
> > separately, then adhere them with double-sided sticky tape and drill.
> > For small boards, I do both sides on one piece of PCB and cut them
> > apart, saving time.
> >
> > Two 0.16 taped together yeild a 1/32" DS. If you add two 0.008 outer
> > layers it's a bit thinner than standard 1/16" boards (the copper and
> > tape add thickness). However, it's much easier to cut 0.008 and 0.016
> > than 1/16" - so I do most of the cutting *before* taping, then sand or
> > file the edges smooth afterwards.
> >
> > Also, the thinner boards work much better in the laminator.
> >
> > I do have some 1/16" stock but as it doesn't fit in the laminator, I
> > only use it when I need the extra strength.
> >
>
>  
>


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