1. What is ESD (Electrostatic Discharge)?
Fundamentally, ESD (electrostatic discharge) is a discharge of static energy that emits heat, light, and sound.
However, in electronics manufacturing, ESD mostly occurs at micro scales invisible to our senses of sight and sound.
This is problematic because we cannot detect it easily. In fact, most ESD damage can only be seen with the aid of a microscope.
Worse, we know from controlled testing that simply having an ESD Program that mandates all personnel wear wrist straps and use ESD safe transport materials can significantly reduce device failures. In 1983, Western Electric found that implementing an ESD Program reduced up to 75% of the device failures they were experiencing at one of their plants. Imagine what that number would be today for a company manufacturing smartphones.
Hence, it makes sense to standardize the rules for how everyone in your workplace handles circuit boards and components into an ESD Program. In the United States, implementing an ESD Program involves standardizing ESD Grounding Methods at your workplace, and carrying out regular ESD Testing to ensure all equipment is in compliance with ANSI / ESD Association standards.
2. The Role of Static in causing ESD
ESD is caused by the presence of static on the surface of materials: tables, chairs, floors, tools, bags, our clothes, and our skin. In fact, anything that insulates is a potential source of static electricity.
Materials that insulate prevent the loss of heat or keep out sounds by slowing down electrons- this also causes static.
If enough static builds up on the surface of an insulator it can be channeled into bottlenecks that cause it to be released as electrostatic discharge (ESD), which is what damages electronics.
For static control, we want to use materials that give electrons the green light to go as fast as possible to ground, or the yellow light to speed up so that they are not static.
“Anti-static” materials: mats for static on tables and floors; smocks for static on your clothes and skin; and static shielding bags for electronics and circuit boards should all be used as part of your ESD Program for your workplace.
What about if you have dry air? Low humidity is a known cause of ESD. If you are working in low humidity consider using ESD air ionizers above your workstation to blow static off your work area.
An air ionizer creates a swath of positive and negative charged ions to prevent electrons in the air from becoming positively or negatively charged and the airflow prevents them from becoming static.
While not all unknown device failures at your facility may be ESD related, enough studies have been done to show that you are taking an unnecessary risk by not having an ESD Program.
Consider reading up on the differences between anti-static materials, and you will be able to better identify which ESD protection products are appropriate for your ESD Program.
- Western Electric North Andover Works (1983). “ESD – How Often Does It Happen?” G.T. Dangelmayer, EOS-5, pp.1-5, 1983.