Q: Why is “Antistatic” not always the answer for static control?
A: “Antistatic” means minimal generation and/or retention of an electrostatic charge. However, it is often misused as a broad term to describe items utilized to control the effects of static electricity.
Antistatic is used as a broad term, but has a very specific meaning. You would measure Charge Decay or the Electrostatic Field to ascertain if a material is “antistatic” or “low charging”. A resistance meter would not be used, as it has nothing to do with resistance; metal is not antistatic, but it is conductive.
Common, but incorrect usages of the word “Antistatic”
“Antistatic wristband”- wrist-bands are not actually antistatic, but conductive around the inner & insulative around the outer surface.
“Antistatic mat” – bench mats used when assembling ESDS (Electrostatic Discharge Sensitive) components, PCB’s, etc. are not antistatic, but have a dissipative top & conductive bottom layer.
“Antistatic box” – black conductive boxes used to store or transport ESDS devices are not generally antistatic.
“Antistatic bag” – mistakenly used for metal shielding (Faraday Cage) bags, which are silver in colour; antistatic bags are generally pink in colour and will not offer protection against an ESD.
Antistatic is different to and therefore should not be confused with terms such as conductive or dissipative. The main difference between an antistatic and a conductive/dissipative material is that the conductive/dissipative material is designed to allow the free flow of electrons, i.e. it is groundable. One material could be completely insulative and have antistatic properties, and another be highly conductive and not antistatic.
Also, we need to make sure we are using the correct equipment to test a material’s inherent properties. To ascertain a material’s antistatic properties, we would measure its charge decay or the electrostatic field it generates. However, conductive/dissipative properties are measured with a resistance meter.
Therefore, when we seek to shield ESDS devices against an ESD, we need to be aware that sometimes antistatic products are not the answer. Instead, often we will require conductive or dissipative products, which are essentially groundable and/or offer shielding of our ESDS devices.