Daily testing goes without stating in a facility that has tight controls. One place I worked at, you could touch the test button with your thumb and with your finger touch the metal pole lightly and pass the ESD test without even stepping on the pad. Same was true of the wrist strap test. They wouldn't listen to me when I pointed out this flaw. Then again, many people would just test and sign that they passed - even when they didn't. Luckily, they were only making blender control boards. I also remember the ESD lotion - had absolutely no silicone in it. That was because silicone can interfere with solder ability.
I like what GopherT said about stress testing a couple sacrificial parts. A waste of parts if you fail to learn something from it. Personally I wouldn't have thought to suggest that or even try it. But I remember testing boards for hydroscopicity: Three types of boards, three boards each, three different tests: One test stored the boards in a tub of water for three days. One test stored the boards in a 250˚F oven for three days. Three boards were untouched and left in their shipping bags. After the test all the boards were run up the wave solder. The boards stored in the oven soldered the worst, but were not at all bad for soldering. Just a little minor non-wetting. The three boards stored in water actually soldered better than the baked boards. The best boards, with hardly any difference from those stored in water soldered just fine. The purpose of the test was to determine the need for baking boards before soldering. The notion was that water would outgas in the wave and cause all kinds of problems with soldering. Turned out to be not true. The point is that sometimes destructive testing is necessary to learn what parameters will work best. In the case of MOS & CMOS, it's been my experience that the best protection is just the grounded mat and the grounded wrist strap. 1 meg or 10, the point is there's a path to ground and a current limiting resistor to protect everything and everybody from accidental shock at 120 VAC 60 cycle (or 240 @ 50 cycle).
Interesting remembering all this fun stuff. Most recent experience with ESD was November 2014. Company I did some contract work had a pretty good system, one you couldn't fool. Had to use your badge to run the test, and then the test results were automatically recorded in the company computer. And there were no exposed metal bars you could fool the test with. THEY had it going on as far as ESD was concerned. They did all three, Automotive, Medical, and Aerospace/Defense work.
I like what GopherT said about stress testing a couple sacrificial parts. A waste of parts if you fail to learn something from it. Personally I wouldn't have thought to suggest that or even try it. But I remember testing boards for hydroscopicity: Three types of boards, three boards each, three different tests: One test stored the boards in a tub of water for three days. One test stored the boards in a 250˚F oven for three days. Three boards were untouched and left in their shipping bags. After the test all the boards were run up the wave solder. The boards stored in the oven soldered the worst, but were not at all bad for soldering. Just a little minor non-wetting. The three boards stored in water actually soldered better than the baked boards. The best boards, with hardly any difference from those stored in water soldered just fine. The purpose of the test was to determine the need for baking boards before soldering. The notion was that water would outgas in the wave and cause all kinds of problems with soldering. Turned out to be not true. The point is that sometimes destructive testing is necessary to learn what parameters will work best. In the case of MOS & CMOS, it's been my experience that the best protection is just the grounded mat and the grounded wrist strap. 1 meg or 10, the point is there's a path to ground and a current limiting resistor to protect everything and everybody from accidental shock at 120 VAC 60 cycle (or 240 @ 50 cycle).
Interesting remembering all this fun stuff. Most recent experience with ESD was November 2014. Company I did some contract work had a pretty good system, one you couldn't fool. Had to use your badge to run the test, and then the test results were automatically recorded in the company computer. And there were no exposed metal bars you could fool the test with. THEY had it going on as far as ESD was concerned. They did all three, Automotive, Medical, and Aerospace/Defense work.
