Use of ESD clothing in an electronic manufacturing process 5

[MJes]

Hi.
I'm new in the electronic manufacturing process, and I want to know if the use of ESD clothing helps to reduce the damage to the components, or this could be redundant when all the production lines are properly grounded and the people uses Wrist and leg straps and they are verified every time they enter to the production area.

Regards

 

[IRstuff]

You cannot rely on a single line of defense. If the grounding strap fails for some reason and you are walking around like a thundercloud; that would be bad. However, if your ESD garb dissipates the energy before you even put on the strap, then like is better. Since the converse can also be true, you need to have both, just like you also need the ESD bags, trays, and totes.

TTFN
faq731-376

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Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

 

[mcgyvr]

There are hundreds of "ESD" specific products from clothing to totes to mats to tools to paints to carpets,etc... A proper evaluation is required to determine whats acceptable/needed for your particular application/product line.
But IRstuff really answered your question.. "Never rely on a single line of defense"

 

[VEBill]

ESD smocks are designed to keep the employee's static filled clothing away from the ESD sensitive product.

Grounding the human (through a safety resistor of course!) is fine, but it does next to nothing about the charge build-up on his/her clothing if that clothing is extremely insulating. And if the clothing is static filled, then it's almost certainly extremely insulating.

It's simpler to use smocks than to try to regulate the employees' clothing choices.

 

[Comcokid]

You can't really regulate personal clothing choices properly, and that also puts some of the cost burden on the employee. Synthetic fibers are terrible for ESD, and some employees personal preferences makes them a walking Van de Graaff Generator. A large circuit board with very sensitive ESD components does not even need to be directly touched to get stressed or damaged. Think of the board as one plate in a capacitor, and the employee as the highly-charged other plate. If they are charged, just walking by close to the board could collect enough opposite charge in the board to cause damage (again, I referring to very sensitive components). Actual damage to the board may not result in a full failure for months.

 

[VEBill]

Or, as applies to ESD smocks...

"...and the employee's clothing as the highly-charged other plate."

The employee, being made of reasonably conductive meat, can be kept discharged through ground straps, etc. A sweater made of synthetic fibers has to be addressed through slightly conductive smocks

 

[MikeHalloran]

I used to work for a medical electronics company, and investigated a plague of ESD field failures of motherboards with CMOS components.

So far as I could tell, the root cause was that the ESD coating normally applied to Tyvek disposable lab coats produced a lot of unsightly 'dandruff', which displeased our medical doctor type customers, so we were paying extra to buy labcoats without the ESD coating.

I recalled the inventory of special labcoats and ordered ordinary coated ones, and the ESD problem went away. ... or at least I didn't hear about it anymore.





Mike Halloran
Pembroke Pines, FL, USA