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Vol. 6
March Issue
Year 2005
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Articles


in Vol. 6 - March Issue - Year 2005
What Could Possibly Go Wrong?


By Giovanni Gregorat, Sales Manager, Pometon S.p.A. Venice, Italy

The report came in just as the editors of this magazine were asking me to write a few lines on the hands-on demonstration which I have been giving at MFN shot peening workshops.

An important aerospace industry had claimed that the grain size distribution on a recent delivery of ASH 110 was out of specification. Between their reading and ours, there was a whopping 15% difference on one of the sieves! How could this be? Sieve analysis is certainly the less sophisticated of quality checks and rarely is it a matter of dispute between manufacturer and end user. All you have to do is pour a small quantity of shot into the top sieve, turn the machine on and read the results. What could possibly go wrong?

My mind goes back to the eager faces of the participants at our workshops. "A proper sieve analysis begins with proper sampling," I lecture sternly. "Peening media will separate during transportation and if you simply scoop up a small quantity from the top of the package, you won’t be getting a truly representative sample. Make sure your sieves are stacked in the proper order and check them periodically for holes or for leaks between screens and frames," I continue. As they scribble diligently, I ponder the fact that even well-maintained and calibrated equipment will never give the same results twice. What could possibly go wrong, indeed!