Occasionally we are asked “how do you ground an insulator?” Since an insulator is a non…conductor, by definition, it cannot be grounded. What ESD control process is used to deal with insulators? The answer is ionisers or neutralisation.
The primary function of an ioniser is to neutralise electrostatic charges on insulators and isolated (nongrounded) conductors to reduce the magnitude of electrostatic discharges in the ESD protected area. Point-of-use compressed gas ionisers combat electrostatic attraction (ESA) neutralising charges on particles that otherwise cause contamination or visual defects on products.
A common example of insulators and isolated conductors is a populated circuit board where the board is a process essential insulator and often components on the board are isolated (non-grounded) conductors. Most companies handling electronics have such sub-assemblies in their products.
The primary function of ionizers with regard to ESDS items are:
- To remove / neutralize charges from process necessary insulators, which can charge ESDS items, thus creating the potential for a damaging CDM [Charged Device Model] event
- Remember that the PCB substrate is a process necessary insulator and can become charged during automated handling processes
- To remove / neutralize charges from a charged, isolated/floating conductor, which, when grounded can result in a potentially damaging CDM event
- Remember that during automated handling processes, the ESDS devices on the PCB are isolated or floating conductors