In a message dated 7/31/00 7:43:51 PM EST, [log in to unmask] writes:

<< We require our Reflow ovens to be calibrated and more importantly, to be
under process control.

 Currently we use a thermal profiler to check the oven and use the profiler
to determine the profile for each type of board put through.

 What is the best way to ensure that the oven will produce good results with
the minimum of fuss.

 I understand that a our profiler which thermocouples are soldered to the
board, does give an indication what the PCB is subjected to.
 The other method is to have thermocouples connected to the oven but it does
not give a true indication what is happening to the PCB,

 Can anybody help.

 Regards,

 Mick >>

Hi Mick!

Ahhh, the ol' oven calibration thing! I've run into that before. I have a ECD
M.O.L.E. (and that is calibrated regularly, rather than the daunting task of
calibrating each thermocouple in the oven). What I've done that satisfies
most people is to create a "calibration profile"...150-degrees C. across all
zones at a fixed belt speed (you can use whatever you want, I use 30-inches
per minute).

Then run my MOLE through the oven with the thermocouples hanging in the air
in a fixed position that is spread across the width of the conveyer to create
a baseline plot.

I then run that same profile monthly and print out the graphic. You can
compare each plot from month to month and keep it on file to show that the
oven is staying consistent. Of course most ovens will tell you when something
is outta' whack, but this usually satisfies most auditors....

-Steve Gregory-

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