Choosing the Right Mat Material, Part 4

By Michael Patino on 2007-08-17 17:41:16 -
As a continuation of last weeks post, I will continue on the different characteristics that you should look for in a mat for your ESD application to ensure that you are running workstation that is up to ESD standards.


Construction
Mats are made from solid sheet, multiple layers and suspended particles. Below I will review the 5 different constructions.

HomogeneousHomogeneous (vinyl and rubber)
Homogeneous, or solid, mats consist of the same material throughout the entire mat. These mats usually provide good mechanical service. Electrical performance is usually limited because antistat can only provide aboout 109 to 1010 RTG.

 

 

Three LayerThree Layer (vinyl)
Three layer mats sandwich a conductive metal or carbon layer (called a scrim) between a top surface of homogeneous vinyl and a layer of foamed vinyl on the back. The conductive scrim layer improves the electrical properties by acting as a fast track to move static charge to ground. Th foam back layer provides a cushion for operators and makes picking up parts easier.

 

 

Two Layer(vinyl)Two Layer (vinyl)

This two layer mat uses the same foam from three layer mat and the homogeneous top from solid mats. Since it contains to scrim layer, this mat provides only average electrical performance. It has the advantage of being cost effective.
 

Two Layer(rubber)Two Layer (rubber)
The Top layer of rubber is static dissipative and the back layer is conductive. This accomplishes the same electrical goals as the three layer vinyl mat. Combined with tolerance to heat and chemical, the rubber mat is an over achiever. However, these features come with a cost premium.
 
Hard Mats (fiberglass reinforced plastic)
This sheet material was used primarily for flooring. Its expense and difficulty in sizing the material have limited its acceptance.

For further information on the construction of mats or any other information regarding this topic please check back every week for further posts, or view the SCC's Technical Bulletin Posts.