Workbench surface was ESD safe.?..no ESD mat

[Flyback]

Hello,
I had to sit a soldering test for an interview.
The test involved soldering MOSFETs.

I insisted that I use their blue “roll-up” ESD mat, and connect it to earth via a yellow ESD plug.

However, the manager then came in and said that the workbench itself was ESD safe, and insisted I remove the ESD mat.
The metal frame of the workbench did indeed have metal poppers for connection of leads for the yellow ESD plugs. However the workbench surface just seemed like a standard hard formica surface.

The bench was a bit like the following, but as discussed, they did not have the blue ESD mat on top of it….
https://www.workplace-products.co.u...s/QMP-ESD-Industrial-Workbench-Data-Sheet.pdf

Do you know if these formica type surfaces are really ESD safe? I didn’t have a spare DMM to be able to measure the resistance from the surface to Earth.
I also asked if I could check if their floor was ESD safe (since the guy didn’t know) . Would you agree that even when using a proper ESD mat, one needs an ESD safe floor? (ie, a floor which has a resistance to earth of less than 35 MEGohms to earth ground from any point on that floor....or at least..doesnt generate Static when one walks on it.

 

[Nigel Goodwin]

And you wonder why you fail job interviews?.

 

[hexreader]

You would be paid to do what your prospective new manager tells you to do. Just do the task given, or accept that you cannot take direction from others and go for self-employed.

Why would your prospective new manager want to pay you money every month just for you to defy his/her requirements?

Look at it from an employer's perspective.

 

[Flyback]

OK thanks, in truth, i think the poor chap was a bit out of his depth, and i suspect he is going to get a load of mosfet boards reworked, and blow all the fets with ESD...so i want to contact him to help him.

(by the way, i did everything i was told to do whilst at the interview....i removed the esd mat as asked and did it without complaint)

He buys in all/most his electronics from china, and doesnt know electronics that well.

 

[hexreader]

Apologies, misjudged you. (who the hell am I to judge anyway)
If you did as asked at interview then you did well
Sorry

 

[Flyback]

Why Thankyou.

I must admit ive been googling, but i cant find any evidence that a formica type surface could be ESD dissipative.

I reckon if they could be ESD dissipative, then no one would bother with those roll-up ESD mats.

 

[hexreader]

Even if Formica was dissipative (my ignorant guess is that it is not), it is too smooth to make good contact with circuit boards or devices. Also hard to connect to ground.

ESD protection is an un-exact science, but good ESD precautions can never be bad. Less than best ESD practise leaves room for (never-ending) argument.

At the end of the day - I would follow company policy, which varies hugely company/department to company/department.

I worked in Aviation industry and moved from obsessive levels of ESD protection, to barely-bothered levels as I moved departments.

There seems to be no absolute truth about ESD protection, other than over-the-top is always the safest bet, but expensive.

Just my experience of following local company policy to keep my job, without really being convinced one way or another.

Apologies for random ramblings.

 

[kubeek]

In our labs the tables are esd safe from Elaborate, it is some kind of particleboard with plastic top. We don't need to use any kind of esd mats.
We also have esd floor and antistatic shoes.

 

[Flyback]

Thanks yes, these "ESD tables" look like they have chipboard between the "ESD surface" and the earthed metal frame, so i dont see how they get a low enough resistance to earth ground from the table surface? They dont elaborate on how its done, or even if its done.

ZENI-LIFT 150 ESD height adjustable table

<p>Zeni-Lift 150 ESD The table series has been specially developed for lighter tasks involving electronics: for example, development, service and repairs. Zeni-Lift 150 can carry up to 150 kg and is equipped with 2 LINAK lifting columns with synchron

zenilift.com

 

[JimB]

They dont elaborate on how its done

Why should they?
Most companies don't publish their production processes for all to see.

or even if its done.

Well, I guess that their customers who consider ESD protection to be a critical part of their production process, will test the resistance quite rigorously before putting the tables into service.
If the tables are not up to snuff, then the manufacturer of the tables will hear how bad the tables are very quickly.

JimB

 

[Flyback]

Thanks, yes, though it could just mean a slightly higher field failure rate which doesnt get pointed back to an ESD problem, because they didnt suspect the table.

I reckon a simple test would be to "Plug" the table in to earth....then put some copper tape on the surface, then measure from that tape to earth.

I certainly wouldnt buy the table till id seen that test........it'd be a PITA if the table got shipped, then failed that, then we had to ship it back.

 

[Click-Here]

I was taught the quartz clear looking layered stuff formed on rocks at our lake was called mica.


quora.com (Is Quartz a conductor of electricity?):
Quantum mechanics proved that any material that is transparent is an insulator. Furthermore, any material made of a perfect crystal is an insulator, for example: diamonds.

WIKI:
Formica Laminate is a laminated composite material invented at the Westinghouse Electric Corporation in the United States in 1912. Originally used to replace mica in electrical applications, it has since been manufactured for a variety of applications. Today, the product is produced by New Zealand–based Formica Group, and has been since 2007. The word Formica refers to the company's classic product: a heat-resistant, wipe-clean laminate of paper or textile with melamine resin.


Search words :
mica insulator TO-220 <---(transistor case style)

https://www.alliedelec.com/product/nte-electronics-inc-/nte422/70216006/

Mica is used as an insulator as pic above.
Formica by wiki explanation sounds like insulation properties.

I think you may know more than the boss, which is why you are an employee.