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How Serious is Static Electricity?
seanadams.com asks: "My company is considering the purchase of a small surface-mount assembly line so we can do our manufacturing in-house, and the issue of static control has come up. We've all been told to take ESD precautions when handling electronics, but how much precaution is enough? Obviously we plan to do the easy stuff like making sure that equipment and work surfaces are properly grounded. However, many shops go even further - conductive shoe straps, wrist staps, special flooring, humidity control, etc. The SMT equipment vendor says that it's unnecessary, and I would tend to agree. I've handled tons of electronics over the years and have never been able to attribute a single failure to ESD damage. Granted, Silicon Valley is a fairly humid area so that may be a contributing factor. Has the ESD threat been blown way of proportion by the guys who sell those little grey bags?"
ESD is a very real problem. Don't trust a conveyor belt salesman who says it is not. He will say anything to get the product sold. If that conveyor belt is made of something non-conductive, plastic bins placed on it will generate static. Soles of shoes, if not grounded with a heelstrap geneate static. Once at work, My heelstrap had slipped off. I found this out when I touched my workbench, and got a nasty shock. If I had touched any electronics, they would have been toast! Fortunately, I did not have a system on the bench at that time.
How ya like dat?
Are you serious? ESD is an extremely serious threat. You can't possibly think of setting up a commercial assembly line for electronics and not worry about things like anti-static wriststraps. Serious places install expensive conductive flooring just to mitigate the buildup from walking around.
Why are you asking Slashdot about this? Ask people who know about this.
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Twoflower
I worked for many years as a contractor at a large US-based defense company. They make lots of neat useful things, and some nasty things.
One thing was always stressed, in the hardware departments, in the software departments, in the finance departments, wherever. If you go into a lab, you must have ESD training. At least 3 levels of training existed. Level 1 was little more than awareness training. If something had an ESD warning label, stay clear of it. Don't touch. Etc. Why? The training also emphasized the costs associated with ESD damage to components. A great deal of effort was spent making sure that we all understood that ESD damage to components might not be visible or even detectable at test / QA time, HOWEVER, in the field, the defect rate over time was dramatically lower when ESD controls were in place on the assembly and test / QA lines. This was serious stuff, the examples ranged from deployed PCs going inop after years of reliable service up to air-to-air missiles not functioning due to static damage. In the end, a very large sum of money was spent investigating the effects of ESD on the reliability of components in the field and it was determined that the benefits far out paced the costs of training everyone and taking precautions in the labs.
I now work somewhere much smaller and have a really hard time getting people to believe that ESD is real. I even had to fight a bit to ESD mats at the workstations where we do assembly.
There are a lot of myths and misperceptions surrounding ESD incidents, and I think that people would be well served by understanding that damange to electronic devices is not either fatal or non-fatal. A FET device might have it's gate region severely weakened by an ESD incident, but it would appear to function normally for an extended period of time. Perhaps the thermal efficiency has been compromised because the gate has partially broken down. The added thermal stress on the part over time will lead to early failure. The reason, naively, would look like a bum part or a thermal problem. The ESD problems don't always reach out and slap you across the face with a sign that says: "Zapped by poor assembly / handling techniques".