On 4/7/2013 12:04 PM, Peter wrote:
> Threading a wire through holes is a very bad way to make vias but sometim=
es
> it is the only option. Riveted through holes are supposed to be soldered
> after riveting. Rivets can be hollow and also serve as pin pickups for
> through hole parts, several makes are available.
>
> The good part about rivets is, they are relatively easily inserted and
> riveted with a machine. The bad part is, you need oversized holes and pad=
s
> to take the rivets which can take a standard IC pin after that. Also, the
> simple mechanical machine is VERY expensive. Rivets are sold by many
> suppliers, among them, Farnell I think, they are relatively cheap per hol=
e.
> But installing them without the machine is not a good idea, even if solde=
red
> afterwards on both sides.
>
> I have used the threaded wire method and I use wire bridges made by hand =
all
> the time (single sided boards, milled). Hard to beat 30 minute turnaround
> time on milled single sided boards with the CNC next door. But it took
> almost 2 years to get the wrinkles out of the process and boards need to =
be
> redesigned and reimaged to be manufactured by other means.
>
> Tip: needle nosed pliers make great lead benders for jumper wires. Not in
> the way one would expect. Eyeball the length of the jumper and use the
> appropriate place on the needle nosed pliers jaws to catch the wire at th=
e
> needed width, then bend overhanging ends down using 2 fingers, insert int=
o
> PCB. Perfectly shaped jumper every time.
>
> -- Peter
>
>
I stopped the proto process many years ago when I realized that the time=20
saved was an illusion.

The resulting prototype was operationally so far  from the actual=20
product that many more iterations were needed anyway.
So, I checked carefully and made an actual PCB. It wasn't the final=20
product, but it was close. Best of all, I was able to get
a number of things solved, such as running temperature, shape and=20
function, placement of logo and document numbers, and a thousand other=20
things that were almost impossible to make by "guess". My time is just=20
too valuable.

Find a reasonable low-volume house that will make a board as close to=20
the final production board as possible.

Ya never know, you might get it "right" the 1st time!

-------------------------

Rivets as thru-holes: indeed, you saw 'em on military boards.

In the olden days, when I was young and stupid (I'm old and stupid, now)=20
I worked for a military contractor. The rivets were there because the=20
thruhole plating process was too fragile, and the components wouldn't=20
stay on the PCB after vibration testing. As the parts were reduced in=20
size and weight, it became less of a problem.

--Bob A


--=20

The only place success comes before work is in the dictionary.

VINCE LOMBARDI

--=20
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