Ioan,

Here's an input from my colleague, Art Kramer:

The concern with specific gravity of the flux is diminished with spray
fluxing assuming the spray reservoir is airtight. Without the agitation of
foam fluxing the flux solvents will not volatize and the specific gravity
should remain relatively constant. It is always a good idea however to
regularly monitor the specific gravity but not nearly as often as with a
foam flux system. It is imperative to regulate and adjust as necessary the
amount of flux applied and the direction of the spray nozzles. Once properly
adjusted there should be a uniform application of flux over the entire
underside of the assembly. Also ensure proper adjustment of any air knives
used to remove excess flux. However if the spray fluxer is properly set-up
there should be very little need for air knives. Finally, maintenance with a
spray flux system is essential to good operation. Ensure the spray nozzles
are flushed thoroughly after each use. This is essential if you are using a
water soluble flux because the higher solids content will clog the spray
nozzles if allowed to dry. Although it may seem that spray fluxing is more
difficult to set-up, the advantages are worth the additional effort. Spray
fluxing yields more consistent application and also aids in top-side wetting
due to the increased penetration of flux into plated thru holes.

Good Luck

Lee Whiteman
Senior Manufacturing Engineer
ACI / EMPF
Telephone: (610) 362-1200; Ext. 208
FAX: (610) 362-1290
E-Mail: [log in to unmask] <mailto:[log in to unmask]>


> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Tempea, Ioan
> Sent: Tuesday, January 09, 2001 1:18 PM
> To: [log in to unmask]
> Subject: [TN] Spray fluxing
>
>
> Hi again Technos,
>
> and a Happy New Year.
>
> Badly need some information on the principles of setting up spray
> fluxing in
> our wave soldering process. The main problem I have is that, with the foam
> fluxer, the target was clear, a certain specific gravity of the
> flux has to
> be observed in order to avoid poor soldering and dirty boards.
>
> Now, what do I have to monitor with the spray fluxer?
>
> Thanks,
> Ioan
>
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