You're describing the standard method for volume electronic PCB assembly
anymore. The bare printed-circuit board is treated with a 'solder resist' in
all areas except where the mounting points of the electronic components are.
The board stuffing machine usually glues the components to the circuit board
in the right locations, with their contacts aligned with the mounting points
on the circuit board. Then a metal-mesh conveyor belt draws the circuit
board loaded with components through a molten-solder bath. The solder only
sticks to the mounting point locations and the component connectors (pads or
wires)... the boards are in the bath for only a few seconds. Then they go to
a wash, which is often now a hot water spray bath, then a forced hot air
blow-dry. Its a shame Freon isn't still around, it worked really well for
this kind of cleaning (and for degreasing camera apertures and leaf shutters
as well). Ozone, we don't need no stinkin' ozone! Nice tan you've got
there... <g>
--
Jim Brokaw
OM-'s of all sorts, and no OM-oney...
The things I've learned while purchasing electronic components, circuit
board assemblys and such...
on 4/9/03 9:49 PM, Scott Gomez at scott@xxxxxxxxxxxxxxxxxxxxxxxxxx wrote:
> Almost entirely jives with my memory of the electronics plant for a company
> I once worked for. Insertion machines stuffed in all the components, then
> they were literally floated across a solder pool to solder the whole board
> in one pass, then the entire board was placed in a washer. The washer wasn't
> a commercial dishwasher, though. It was a specialized piece of equipment
> using Freon as the cleaning solution. I'm willing to bet that Freon isn't
> the solvent of choice any more... :-/
>
> ---
> Scott Gomez
>
> -----Original Message-----
> From: lamadoo@xxxxxxxx [mailto:lamadoo@xxxxxxxx]
> Subject: Re: Re: [OM] Dropping things, or never say never
>
> Well, yeah. I read about a tour of an audiophile manufacturer in
> Stereophile.
>
> They had a machine that "stuffed" components into a board, then dipped the
> entire board in heated solder, making all of the joints at once. After
> cooling the circuit boards, they loaded them vertically into a commercial
> dishwasher and ran 'em though a cycle. They said it cleaned off the excess
> rosin. It wasn't the April 1 issue but it did surprise me.
>
> Lama
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