1. Differences between Anti-Static Materials
Anti-Static materials, (those used for static control to prevent ESD), are either conductive or static dissipative.
However, “anti static” can sometimes also refer to the upper end of the static dissipative range (1 x 1010 to less than 1 x 1012 ohms / square). For example, anti static polyethylene used in bags is typically in this range.
The border line between conductive and static dissipative is 1 million ohms / square. This is also referred to as 1 meg ohm or 1 x 106 ohms / square.
Conductive materials are used to speed up electrons at the point of contact so that electricity can be grounded, or as part of a product to “shield” electronics from ESD.
For example, carbon threading is woven into ESD smocks in a grid pattern to make them “static shielding”.
Static Dissipative material is used to speed up electrons so that they are not static, but not speed them up so fast that they cause ESD.
Anti Static bags and mats are the most well known static dissipative materials. In these cases, you do not want electrons to be static, but you do not want them to be moving so fast on the surface of the bag or the mat that they cause ESD.
For example, a typical anti static mat is static dissipative on the top, and conductive on the bottom. This design allows electrons moving on the mat’s top working surface to move slowly to ground, and then speed up as they fall through the mat from the work surface into the Earth below.
Whatever your need is for static control you will need to know the differences between the materials in your workplace. This allows you to identify the variables that could be causing device failures, if you have not implemented an ESD Program yet.