Phil's idea on speed is good, but I have issues with the temperature bit.  Your altitude is going to drastically affect the boiling/freezing point of water, as will the water's purity.  It may be better to talk to the equipment guys (if you have them) and see what procedure they use to calibrate thermocouples and use something along those lines.




Eric Kalgren
BFGoodrich Aerospace
Data Systems Division
[log in to unmask]
(505) 938-5139

>>> Phil Zarrow <[log in to unmask]> 12/16/99 11:59AM >>>
Jim -
The simplest approach is the direct approach.  Regarding conveyor speed, mark
off a measured length on the on-load (or off-load) and time how long it takes
a mark on the conveyor (or a link or pin) to cover the distance.  Calculate
the speed and compare it to the setpoint.  Most ovens have closed-loop
conveyor speed control but it is a good idea to test it.
The way I used to measure accuracy of temperature was to attach a
thermocouple to the the PDI controller (or you can use the inputs for
on-board profile tracking your oven might have come with) and place the
thermocouple first into a beaker of ice and then into a beaker of boiling
water.  The temperature measured by the machine should be 0 deg. C and 100
deg C respectively.
I suppose there are fancier, more "academic" approaches, but this is
practical, simple, economical and can even be incorporated as part of your
ISO-9002 procedures.

Phil Zarrow
ITM, Inc.
Durham, NH  USA
www.ITM-SMT.com 

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