Got distracted by work, if you can believe that, and didn't finish.

You know all this stuff but if your conveyor is traveling at 4'/minute, that
means 1'/15 seconds (great math, eh?). If you use your Lev Chek glass one
inch grid plate and you verify your contact area is parallel and is about
1.5" across, then you can determine your contact time. For more "normal"
boards, depending on your matrix indicators, your contact time should be
about 1.5 - 3 seconds - depending on conveyor speed.

For massive boards, thermally speeking, the contact time may be much longer
as the conveyor speed may be as slow as 1'/minute or less. Scary stuff these
boards and conditions.

Of course, with all this stuff, I'm using through hole technology as the
baseline for the settings. Mixed technoloty will be the same though SMT ohly
types can be more "normally" profiled.

Once sub-process and process "calibration" is done manually, profilometers
may be used as well. Of course, many "trust" the machine's computer if so
equipped. No matter, I still do manual "calibrations" on a regular basis for
computer controlled machines and I do this at the beginning of each new
product lot on less automated machines - all a function of my trusty matrix
having all the "numbers"/paramaters for each board type required. My matrix
then is converted to SPC information as process control charts based on
process effects as acceptable quality solder joints.

I'm done and distracted by work again. Just killing a little time on a very
old subject I don't get to visit that much anymore. What's the company that
makes the Lev Check glass plate again?

MoonMan

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