Used this process with SonoFlux units.

Even coverage it the most important criteria.  To start with the team used a
localized air velocity probe in the exhaust stack above the fluxer to tune
the dampers and achieve laminar flow past the board and into the duct.  This
resulted in even coverage.  Coverage measurements were visual; a glass plate
or paper covered board both work well.  With experience we could judge this
on real product.  In our application, (water based non-voc flux),
maintaining consistency while minimizing flux was critical.  Too much flux
stayed liquid beyond the preheat and produced disastrous results at the
wave.  Uneven coverage would result in a board with areas where the flux had
lost activity prior to the wave and areas where flux remained liquid until
the wave, difficult to determine root cause on the finished product and no
fiddling with settings could fix that.

Once the airflow was set, a DOE provided surprising (yet not totally
unexpected) results.  Optimum settings on the fluxer were extremely
different from the manufacturer's recommendations. We would never have
achieved the success we did trying to "tweak" or fine tune the original
parameters that seemed to solder most of the boards well.

If you choose to run a design of experiments, try to get away from attribute
evaluation criteria like first pass yield, or number of defects, and measure
something quantifiable like average hole fill or rise and deviation.
Settings that give you 75% fill across the board may not be acceptable if
the result is 100% rework; but they bring you closer to the final answer
than 95% acceptable joints and 5% with no almost solder in the barrel. Of
course, if you have to ship product tomorrow to make payroll, go for the
95%, warm up your soldering iron, and fix the process later, hopefully soon.

Good Luck,
Brad Vanderhoof
AITI


----- Original Message -----
From: "Peter L" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 07, 2003 6:04 PM
Subject: [TN] Wave soldering - Spray fluxer parameters


> Technet,
>
> Can anyone recommend a process for setting up the operating parameters
> for the spray fluxer?
>
> How can one verify the optimum amount of flux is being applied to the
> pcb prior to the board going through solder wave?
>
>
> Rgds,
> Peter
>
> ---------------------------------------------------
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/archives
> Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
> -----------------------------------------------------
>

---------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------