THE ESSENTIAL GUIDE TO CHOOSING THE RIGHT ESD MAT

Transcription

1 THE ESSENTIAL GUIDE TO CHOOSING THE RIGHT ESD MAT

2 ESD MATS: WHAT TO CONSIDER One of the most critical pieces of safety equipment in any clean room or manufacturing environment is the antistatic mat. These mats, in conjunction with antistatic gloves and standard clean room equipment, can significantly lower the overall threat of static electricity damaging sensitive electronic products. But as with most safety products, ESD matting comes in many different forms and fashions, in addition to being made with a number of different material composites. Choosing the best ESD mat for your facilities requires comparing these variations and evaluating the advantages and disadvantages of each to take stock of your company ultimately needs.

3 MAT MATERIALS Mats are generally made with two different kinds of material: ESD Vinyl The most widely used material for table top or work surface applications. They are cost effective, easy to cut to shape and provide excellent static dissipation. ESD Rubber Used where high resistance to heat and chemicals is required. ESD mats also come in two different types: ESD Table Top or Work Surface Mats These mats have a smooth or lightly embossed surface and are available in: - Single layer vinyl homogeneous material - Two layer rubber material - Three layer material with homogenous vinyl top, a foamed vinyl back, and a carbon layer in the middle ESD Floor Mats These mats have heavy embossing or grooves to improve traction, and an anti fatigue style to reduce stress. They are also available in dark colors to hide dirt.

4 MATTING PERFORMANCE The performance of a specific static mat is dependent on the materials with which it is made, and their electrical properties, tolerance to heat, chemicals, and mechanical abrasion, and cost. To work properly, a mat must be able to conduct electricity at the appropriate range. If the mat s resistance is too low, static will transfer to the mat and create a spark, causing electrostatic discharge (ESD) and damage to electronic devices. If the mat s resistance is too high, static will transfer to the mat slowly. Items on the mat will not lose their charge, but, once removed, will be capable of discharging to other items.

5 TEST METHOD To test static mats, two electrical measurements are made: RESISTANCE TOP TO TOP (R TT ) This test measures the resistance between two widely separated points on the surface of the mat to confirm that all areas of the mat conduct static at the same rate. The measurement also exposes cut or damaged center layers in multi-layer mats. The EOS/ESD Standard 4.1 guideline for R TT is > 10 6 ohms. RESISTANCE TOP TO GROUND (R TG ) This is the most important electrical test for mats showing a mat s ability to conduct static from a point on the mat s surface to the mat s ground point. EOS/ESD Standard 4.1 guideline for R TG is < 10 6 to 10 9 ohms. In addition to the electrical measurements described above, the following is also tested: SURFACE RESISTIVITY This test does not reveal much about the mat s ability to perform correctly, but it does allow differentiation between ESD mats and non-esd mats. Because dirt can act as an insulator on the surface of the mat, this test is useful for monitoring the mat after cleaning. By monitoring this resistivity, a cleaning schedule can be arranged.

6 CHOOSING THE RIGHT MATTING ESD mats can be made from solid sheets, multiple layers, and suspended particles, offering differing electrical performance. HOMOGENEOUS (VINYL AND RUBBER) Homogeneous or solid mats consist of the same material throughout. These mats provide good mechanical service with electrical performance normally limited to about 10 9 to R TG. DISSIPATIVE VINYL OR RUBBER THREE LAYER (VINYL) Three layer mats are constructed from a conductive metal/carbon layer sandwiched between a top layer of vinyl and a bottom layer of foamed vinyl. The inner conductive layer improves the electrical properties by acting as a fast track to move static charge to ground. The bottom foam layer provides a cushion for operators, making it easier to pick up parts. DISSIPATIVE VINYL CONDUCTIVE METALLIZED LAYER DISSIPATIVE VINYL FOAM

7 CHOOSING THE RIGHT MATTING (CONT.) TWO LAYER (VINYL) This two layer mat combines the foam layer of the three layer mat with the dissipative vinyl of the solid mat. Because it contains no metallized layer, the two layer mat is a more cost effective option. However, because of that absence, it provides only average electrical performance. DISSIPATIVE VINYL DISSIPATIVE VINYL FOAM TWO LAYER (RUBBER) This option provides a top layer of static dissipative rubber and a bottom layer of conductive rubber, giving it the same electrical performance as the vinyl three layer mat, with great tolerance to heat and chemicals. This type of matting does come with a cost premium worth considering. DISSIPATIVE RUBBER DISSIPATIVE RUBBER FOAM

8 CHOOSING THE RIGHT MATTING (CONT.) The following guide is meant to help you in selecting the right ESD mat and the right ESD mat material for your application: MAT TYPE FEATURES TABLE MATS Light colors make finding small parts easier Smooth or lightly embossed surfaces Usually thinner than floor mats FLOOR MATS Dark colors hide dirt and grime Heavy embossing or grooves to improve tractions Usually thicker than table mats to absorb more wear MAT TYPE ELECTRICAL PROPERTIES USAGE FEATURES R TG R TT HOMOGENEOUS table/floor durable material THREE LAYER table excellent electrical properties TWO LAYER VINYL table low cost TWO LAYER RUBBER table heat/solder tolerant chemical resistant excellent electrical properties

9 FOR MORE RESOURCES OR TO ORDER ESD MATS: VISIT ANTISTAT.COM CALL