How to Determine ESD mat dimensions for work bench?

[Amaterasu]

Good day, Fellow Covers!


I have a question: how to determine ESD mat dimensions for a work bench?

Our company deals with electronic repairs and the Business Unit I'm assigned, repairs set top box converters (cable box decoders). Since, ESD products are expensive, I wish to reduce the cost by suggesting appropiate ESD mat dimensions for our work benches area (30" W x 60" L).

Thanks in advance!

 

[Icy Mountain]

Re: How to Determine ESD mat for work bench?

Amaterasu,
Hello and welcome to the Cove! I am running an ESD control system that is compliant to ANSI/ESD S20.20-1999.

We have about 50 wooden topped benches that measure 34" x 72". We use a standard 24" x 48" ESD mat on each bench. This is no big deal. Every inch of your bench does not need to be covered with ESD mat. The only thing you need to make sure of is that your people are trained so that they know that they are only ESD safe if the product is on the mat and they are connected via wrist strap to the mat.

-Icy

 

[Amaterasu]

Thanks, Icy Mountain!

What type of electronics does your company manufacture/repair?

Your benches are actually a little more big than ours.

I'm providing trainings to our personnel and stressing the importance of taking care and encouraging them to tell our supervisors and engineers when ESD mats, personal and table groundings look damaged or bad so, we can take proper actions to change them.

Have someone asked you about how to determine the ESD mat area?

 

[Icy Mountain]

We design and manufacture power conversion equipment. DC to DC, DC to AC, AC to DC. Some are brute force, others microprocessor controlled, some through-hole, some surface mount, some hybrid, but all have Field Effect Transistors that are very ESD sensitive. Some weigh over 75 lbs. so our benches are sturdy. 2" maple butcher block benchtops to avoid marring the painted surfaces.

You are actually the first person to ever ask me about dimensions of the mat versus the bench. That includes a lot of operations managers, internal, external and customer auditors over the years. As long as your mat is larger than your product you are fine. Visualize a products that are roughly the size of microwave ovens, smallest to largest. Can you see a way to assemble that somewhere other than the 2 x 4 foot mat when working on a 3 x 6 foot bench?

Take a look at this page from my distributor's website. Looks like they have 30 inch by 50 foot rolls but you have to cut them and install your own snaps for the straps. If you want to save a lot of time, trouble and questions, use the standard 24" x 60" mat and be done.

 

[Amaterasu]

Thanks, again!

I asked this question because for the case in someone from our higher up management questioned me about it. And I wish to have a good background to support the ESD mats' area size.

Also, we are moving to another location and many of our ESD mats have a heavy wear and have pen and pencil markings on them.

Regards,


Alfredo.

 

[Icy Mountain]

They also make special cleaners for ESD mats. They can be expensive so we use a different solution. First, if there is anything sticky on the mat we use a standard citrus oil cleaner that you can buy at any grocery store. We have 99% isopropyl alcohol (don't use 80% "rubbing alcohol" as it contains other ingredients that you don't want on your mats) in our plant already as a flux remover so we use that to remove the oily residue from the mats. It also removes grease, most ink, pencil, etc. and does not damage the vinyl mats. You'd be surprised how good an old mat can look after this treatment.

 

[Amaterasu]

Good day, Icy Mountain!


Yes, ESD products are pretty expensive and money should be expended wisely.

I'm going to try your cleaning method which I suppose is ESD safe, right? (It is because of citrus oil cleaner; any brand in special like "Orange Glow"?)

 

[Icy Mountain]

Orange Glow ought to work fine. We use a product called Citrus Power from Neutron Industries. You definitely need to remove the citrus oil from the mat after using it to clean the mat. The oil does interfere with the dissipative properties of the mat after multiple uses if it is not removed. You can clean with the oil first and then with alcohol or just use alcohol.

Most ESD mats are rubber or vinyl, so they are not very resistant to aggressive solvents. Unfortunately, most of the mess that gets on ESD mats needs a solvent to remove it. Citrus oil and isopropyl alcohol are relatively mild solvents that have two important properties: 1) They do a pretty good job of removing most goo and dirt; 2) They don't tear up rubber, vinyl or bare skin.

I have been measuring my mat to ground resistance, with a calibrated megohm meter, for 7 years. I have 8 mats in a row on a manual assembly slide line that have been cleaned with Citrus Power followed by isopropyl alcohol every Friday for the past 7 years. They measure the same as when they were new (and they still look pretty good, too).