Russ, On both instruments, I ran them through the wave 20 times each using identical profiles and wave parameters, and then used statistical formulas to measure the variation and repeatability of each. I had these all in Excel, but that was around 1999.I'll try dig this up somewhere... The parameters which I felt were worth measuring were:
1.) Dwell Time 2.) Contact Length 3.) Parallilism 4.) Delta T (temp delta before the last pre-heat and chip wave) 5.) Conveyor Speed
Note: #'s 2&3 can be derived from 1&5.
Don't use immersion depth. It's a bullshit measurement and neither device had a reliable method to measure theis.
Each gave slightly different readings but both were within 0.5 seconds, and 10 Deg. remember, each instrument's got its own thermal coupon as well so your delta T's will vary a bit.
I would get a statistics book, or google GR&R formulas, or use a statistical software like MiniTAB. If my memory serves, I believe I used traditional statistical formulas like average & standard deviation and the formula for instrument repeatability.
In the end, the WaveRIDER fared a little better, and as others stated, the SPC software was nice. I also liked it better than WaveRIDER because it used the MOLE as its brains, and you could do other stuff like run the Wave Rider whilst profiling a board behind it. At the time, too,I was a MOLE loyalist. The Wave Optimizer, although pretty good when it worked, had some not-so-good features (that ripoff $300 replacement battery pack), and lame software.
The key to success in implementing this is to train the proper personnel to run this, and have a reaction plan in place if one of your measurements falls outside the control limits. In my experience, when I was at a big OEM in Riyadh with 10 lines, the GOOD operators always called me out to the floor during an out-of-control condition. Others didn't bother running it. (we had one on each wave). So, again, half your battle will be getting the proper personnel to run this. At my 1st small company, we used the Optimizer on just one very old 1980's Econopak and it worked great! So, it all depends on how your shop is run.
Okay...enough rambling for one night. Damn, I should move to America and consult for you guys. At least they don't saw your hands off! :)
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