ESD Prevention Strategies- BUSTED!
In a previous blog from back in the day, ten myths about electrostatic discharge were explained. It is informative, and you should read it. But this blog is aimed at prevention strategies, specifically those that aren’t, actually.
A summary, before we get started: electrostatic discharge (ESD) happens when two electrically charged objects have a sudden flow of electricity between them. Like when you touch a doorknob and get shocked, or kiss your child goodbye and shock them, or your beautiful mane sticks to clothing and you hear sparks when you pull it away. Normally this is harmless, but not so with circuit boards and other sensitive electronics. ESD can cause a range of problems from minor glitches to total failure, and employing multiple prevention methods is vital since ESD will never go away. There is another blog about which prevention methods actually work (think wrist straps, heel grounders, anti-static matting, ground cords, and anything labeled “antistatic”) but today we focus on what intelligent people are saying on the internet…
- ESD is only a problem in the winter, so do your electronic work in the summer. No. Items are being charged and discharged all the time- it never stops. It’s just that drier air (winter air) allows the charges to build up to a greater degree and there’s little humidity to dissipate it quickly and more evenly.
- Engineers don’t generate static, so ask them to help. You might start to believe this after you’ve seen some of their desks- so many parts, like a little metal mountain. Who knows- maybe that’s the pile of shocked stuff… Engineers may be pretty cool, but they’re still human beings and “a human being is represented as a capacitor of 100 picofarads, charged to a voltage of 4000 to 35000 volts. When touching an object this energy is discharged in less than a microsecond. While the total energy is small, on the order of millijoules, it can still damage sensitive electronic devices.” Now, that was from Wikipedia and you know what they say about Wikipedia. So maybe this one is true.
- ESD bags (the bag the electronic came in) make good workstations. Uhm, no. Great that your device came in the special bag, but it was only protected while INSIDE the bag. Simplified, ESD bags are designed to be non-conductive on the inside and conductive on the outside, as a means to dissipate the charges that are inevitably happening around it. So if you use the outside of the bag as a workstation, you are working on a conductive surface.
- The foam that surrounds my parts during shipment make good workstations. The internet gurus seem divided here, but you should err on the side of no. There are different types of foam: anti-static, conductive, and dissipative, and some come in certain colors, like pink or black. The way some of them work is by keeping the voltage consistent across all points of the board, thereby eliminating high and low points, thereby protecting the board. But this means the foams is conductive to some degree and if you’re moving your parts around on it- well, that seems to be asking for trouble. Best to keep the shipping foam employed in it’s one task- protection during shipment. And if you’re wondering about ESD-safe packing peanuts- they don’t exist.
- I’ll just work in my bare feet. Okay, that would actually help. But since it only “helps” (bare skin builds up a charge at a slower rate than socks) and it just may not be practical, best to adopt some other strategies.
- Since humidity is the issue, I’ll buy a humidifier for my workspace. Humidity isn’t the issue, life is the issue. Remember, static will still build up in a more humid environment, just at a slower rate. The problem here is that while increased relative humidity WILL help (ideal levels are 40-70%), preventative measures that involve grounding should still be taken, and if your environment gets too humid, you will start to combat the dreaded C-word. Corrosion.
Now that you know what you’re doing wrong, go find some products by QRP, ACL, Chemtronics, and many others to help you manage ESD correctly. The easy way? Type “antistatic” or “ESD” into the search bar at GoKimco.com