ESD worksurfaces, such as mats, are typically an integral part of the ESD workstation, particularly in areas where hand assembly occurs. Carts or shelves where ESD sensitive items are stored (without ESD shielding) would also be treated as an ESD workstation. The purpose of the ESD worksurface is two-fold:
- To provide a surface with little to no charge on it.
- To provide a surface that will remove ElectroStatic charges from conductors (including ESD Susceptible devices and assemblies) that are placed on the surface.
ESD mats need to be grounded. A ground wire from the mat should connect to the common point ground which is connected to ground, preferably equipment ground. For electronics manufacturing, a worksurface resistance point to point (Rtt) of 1.0 x 10^6 to less than 1.0 x 10^9 ohms is recommended.
The best practice for grounding is that ground connections use firm fitting connecting devices such as metallic crimps, snaps and banana plugs to connect to designated ground points. Use of alligator clips is not recommended.
The worksurface must be maintained and should be cleaned with an ESD cleaner. Regular cleaners typically contain silicone. They should never be used on an ESD worksurface because the silicone will add an insulating layer. The ESD control plan should require testing the resistance to ground periodically. However, the operator should be on guard every day and check visually that the ground wire is attached.
For more information, contact Desco.