Try using a robotic coating machine.

I have used both (at different employers) Nordson and PVA equipment and
eliminated all masking such as what you are suggesting. SCS also makes
similar equipment, but I haven't used it in production. You also have the
advantage of coating components on either side above the dip line.

Another option I have used are cheap throway booties and plugs. Custom ones
can be made for under $1,000 tooling.

I have also used precut adhesive tape dots (and custom shapes) to mask
contact surfaces. They go on and off fast.

Aric Parr
Sr. Process Engineer
Eaton Corporation
1400 S. Livernois
PO Box 5020
Rochester Hills, MI 48308-5020
248 608 7780
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---------- Original Text ----------

From: C=US/A=INTERNET/DDA=ID/TechNet(a)IPC.ORG, on 9/6/99 3:33 AM:

For some additional info on what we are doing..

We are currently having to mask off on a typical board, 4 x 4.5mm hole
with large lands, 1x3mm hole with large land, 3x1.5mm hole & 4 pads for
LED's.
All but the LED's are too big for screened on peelable resist(drips
through), and we cannot apply that to the SMT side.

Once the board has been placed, reflowed & ATE tested, the above is done
to both sides (takes ages).
Then they are put to one side for a few hours for the masking to cure.
Then dipped & hung in a cabinet to cure overnight.
Then the masking has to be peeled of each individual pad (taking ages
again).

There are 12 boards per panel & done in batches of about 2000.

And that's only one product, we have lots more like it.

As you can see this adds a considerable amount of time to the production
times for this product.
If we could automate this better to reduce the time it takes to make
these products, everyone would be far happier.

Matthew Lamkin
Printed Circuitboard Draughtsman
Protec Hse, Churchill way,
Nelson, Lancashire.
England UK.
Email [log in to unmask]

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