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We are a manufacturer of polyester fiberglass-reinforced Trays. These trays are often used with a dual-layer static dissipative/conductive mat. The majority of sales into electronic assembly companies are of conductive trays. Should I convince our customers it would be better to use trays in the static dissipative range rather than conductive? - Anonymous, Oconomowoc, WI

Dissipative surfaces are preferred over conductive ones for ESD Control in the electronics industry. Conductive is defined as having a surface resistance below 1x10^4 ohms. When a surface is too conductive, a charged device can easily discharge (undergo an ESD event) upon contact with a conductive surface wheather it is grounded or not. This is the threat of the charge device model, where a charged device comes into contact with a conductive material and discharges (an ESD event occurs).

Most ESD Control programs are very good at protecting themselves from the Human Body Model (HBM), but not the Charge Device Model (CDM). The use of dissipative mats and surfaces greatly reduces the problem of CDM.

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