By simply moving, a person creates static electricity. Under these circumstances, making contact with a conductive material will result in a sudden discharge of static from the body. This discharge is ESD = Electrostatic discharge. Static electricity is becoming a serious problem in the electronic manufacturing industry. Usually, this goes unnoticed because we do not feel electrostatic discharges under 3000 volts. We may see ESD above 5000 volts as a spark. A lot of standard components are sensitive to charges of 100 – 200 volts and the most sensitive electronics can be damaged by a charge of just 30 volts. When manufacturing electronic equipment, it is vital to measure your ESD control regularly and correctly.
Below are some essential tips for measuring all the parts of your ESD workstation.
- · When you measure your ESD control on your work surface, place your probes on the tabletop, spaced at least 25 cm apart and at least 5 cm from the edge of the top.
- · With shelves and tables, place one probe on the work surface and the other on the shelf or table. Your point-to-point resistance should be < 1x10⁹ Ω
- · With flooring, place one probe on the work surface and one probe on the ESD floor. Point-to-point resistance should be < 1x10⁹ Ω
- · Test the common point ground by placing the probe on the tabletop and measure the system’s total resistance between the tabletop and the common point ground using a measuring lead.
- · Chair ESD, place one probe on the seat of the chair and the other on a metal plate under one of the chair’s wheels. Your point-to-point resistance should be < 1x10⁹ Ω (with upcoming standard < 1x1010 Ω). For best results, make sure chair wheels have been cleaned with ESD detergent.