26 Feb

Can ESD Wax be applied to bring back dissipative properties?

Q: Into our manufacturing area we have a dissipative floor installed, some areas has lost the dissipative properties, we are using ESD wax to correct those areas.

We are not having good results, we measure point to point and point to ground and these areas still measure insulative, my question is:
The ESD wax only works in floors with dissipative properties, or could it be applied on areas where the floor has lost the dissipation properties?”

A: Thanks for contacting us.  This is one of those questions that I like to pounce on, because it brings up many current misconceptions in the ESD flooring industry.  I’m going to answer your question about using chemicals to perhaps patch up certain areas in your flooring system, but I’m going to reach beyond that question and give a comparison of the ESD flooring system vs an otherwise non-ESD flooring system with an ESD sealer applied to it.  We supply both options here, by the way.  I hope you find what you need here and that this response helps guide you in your application.
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04 Feb

How to measure ohms of ESD Chair back rest

Q: Hi, I am a fresh ESD engineer. I need to perform a testing on ESD chair by using 5 pound Megohmmeter. I encountered a problem when I was trying to test on the backrest and rear of backrest. The backrest is a vertical plate, how to put a 5 pound electrode perpendicular to that surface? Even ANSI/ESD STM 12.1 2006 also not mentioned clearly about the testing on the backrest. Can I hold the 5 pound electrode by my hands so that it is contact with surface of the backrest? Or is there any other proper way?”

A: Hello,  I understand your frustration with some of these tests.

It sounds like you’ve got all the proper testing equipment and you’re following the best procedures for this.  The main concern is to see that the seat, seat back and arms are making good contact to the personnel, that personnel is wearing the proper clothing so as to enable the combination of personnel to chair to esd flooring system to electrical ground are enabling the tribocharge to recombine to earth.  If you have an ESD chair that includes a static conductive/dissipative seat, back, arms, casters, etc. we can make these resistance measurements to the chair’s groundable point, to a plate sitting underneath a caster, and ultimately, all the way across the floor to earth ground.
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19 Dec

Frequency of testing ESD Technical Elements in an EPA

Q:  We have a number of carts, racks, and chairs in the clean room. When we do our weekly, monthly and semi-annual checks for ESD and grounding, do we do a statistical sample or do we check all of each item. Is there a standard that explains this?

A:  You ask a very valid question and it just so happens that I received a similar question on this not long ago.

I wish there was one and only one ESD Bible that’s all inclusive and complete; from design to audit. The ESD Association has the ANSI/ESD S20.20-2007 document which gives us guidelines in establishing an ESD control program. But as far as a standard explaining when to audit each and every ESD technical element, I have yet to find a good source. The tables contained within 20.20 will give you “required limits” for various technical elements, but not a frequency of when to audit or test these systems. Between JEDEC Standard 625-A Table 2 of page 9 and other sources, I’ve put together these recommendations, but it’s up to you to implement them and tailor them to your unique processes; Read More

05 Dec

ESD Compliance: Test the ESD Devices, and test the testers

Q: How does a wrist bandcum footwear ground tester differ from the work station monitor? Can we not use only the work station monitor when it can monitor the worthiness of wrist strap even? And, Can we not check the worthiness of a wrist strap with a normal multimeter

A: I think that I understand your question here.  One way or another, a company needs to say what they are going to do in terms of ESD compliance.  They need to then do what they say they will do and document it.  They need to test the ESD devices.  They then need to test the testers.  And they need to show records of such in a pass/fail document and to prove that they are committed to quality and do not accept anything into the environment than will lead to a failure.

A wrist strap/footwear tester is proven and tested.  It is convenient to monitor and record the compliance to a whole shift of people in a given EPA.  But what if someone tests their wrist strap that morning and it fails at 10:25 that morning.  They won’t know it failed until later that day. 

The advantage of the constant monitor is that it not only alarms the moment it fails but it also forces the user to keep it on (wrist strap) while seated at the ESD workstation.  That’s fine.  But you need to test the testers periodically.  And to document those tests.  I hope I understood your question and answered it accordingly.

I suppose you could check the worthiness of a wrist strap with a normal multimeter.  I have a device that measures the connection from a connected 4mm, 7mm, or 10mm snap, through the coil cord and 1M Ω resistor, and two conductive cylinders that measure a stretched out wrist strap.  With it, I can measure the cuff only, the cuff and cord, or the cord only.  It cost me (us) a small fortune.  I have a Fluke 123 Industrial Scopemeter and a Fluke 77.  They are great meters, up to about 40M Ω or 4.0E7.  If you have wrist straps that are conductive enough, then great.  Good luck.  You may need a Megohmmer.