Hi Evan,

I used to have 2 types of spray fluxer, one is using Ultra-sonic transverse
type that make use of air to carry the flux to the board; and the other
using the compressed air to push the flux to the board.

I never had any issue with the top side fillet formation using the
compressed air spray fluxer, but not with the Ultrasonic spray-type.

What I do is make some simple modification to the Ultrasonic spray fluxer,
so that it has more pressure to carry the flux and penetrate through the PTH.

It is very important to have enough air as to carry the flux "through" the
board, as this will help to improve the top-side fillet formation.


Another possibility is due to insufficient fluxing from the spray-fluxer,
you may need to fine-tune your spray system.


Good Luck..

Poh
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======



At 02:49 PM 7/1/98 +1000, you wrote:
>We installed a spray fluxing system on our wave solder machine, based on a
>Nordson pulse sprayer, a couple of months or so back but have been having
>some problems getting good results. The system utilises a single spray
>nozzle with a fan pattern. The problems we have seen are poor barrel fill
>(presumably due to flux not penetrating PTH barrels), and shadowing effects
>on bottomside surface mount components.
> We are using a no clean flux. I tried using an active flux, with the same
>results, which suggests it is the sprayer setup which is the problem. If
>anyone has some experiences that they can share with me regarding
>successful implementation of airless spray fluxing systems I would be most
>appreciative. What factors influence penetration? spray pressure?
>extraction?
>Up until now we have been using a foaming fluxer with reasonably good
>results (except for difficulty controlling no-clean residue levels).
>
>
>Regards Evan
>
>Evan Jones
>Manufacturing Engineer
>Bluegum Technology Pty Ltd
>PO Box 609, Wangaratta, Australia, 3676
>Ph: 61 3 5720 2539     Fax: 61 3 5720 2412
>Internet:  [log in to unmask]
>
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