EEVblog Electronics Community Forum

Electronics => Manufacturing & Assembly => Topic started by: Faringdon on July 13, 2022, 05:33:21 pm

Title: Nylon 6/6 screws cause ESD problems to components on PCB?
Post by: Faringdon on July 13, 2022, 05:33:21 pm
Hi,
Have some control PCBs wired into a main PCB...the control PCBs stand on top of Nylon 6/6 screws as follows...

https://uk.farnell.com/duratool/d01494/hex-threaded-spacer-nylon66-natural/dp/1733426?ost=1733426 (https://uk.farnell.com/duratool/d01494/hex-threaded-spacer-nylon66-natural/dp/1733426?ost=1733426)

The internet seems to suggest that Nylon 6/6 is "ESD static dissipative"....

https://www.copeplastics.com/materials/nylon-6-6-electrostatic-dissipative/ (https://www.copeplastics.com/materials/nylon-6-6-electrostatic-dissipative/)

..so i believe we will not inspire ESD problems to the components on the PCB just because of these Nylon 6/6 screws?
Title: Re: Nylon 6/6 screws cause ESD problems to components on PCB?
Post by: TimFox on July 13, 2022, 05:38:51 pm
The material in your second link is not normal 6/6 Nylon, but Nylon infused with carbon fibers to become ESD-dissipative.
Plain Nylon has a problem with moisture absorption, but is not particularly dissipative.
See the full description:  https://www.copeplastics.com/materials/tecamid-66cf20/ (https://www.copeplastics.com/materials/tecamid-66cf20/)
I have used black polypropylene cable ties that were treated with carbon for UV resistance, but their DC conductivity was very low.  The dielectric loss (at about 10 MHz) was substantial.
The same manufacturer's green polypropylene cable ties did not show substantial dielectric loss.
The hardware in your first link is not conductive:  read the spec sheet for its very high resistance.  Note that the material is natural 6/6 Nylon, not the specialized material in the second link.
Title: Re: Nylon 6/6 screws cause ESD problems to components on PCB?
Post by: T3sl4co1l on July 13, 2022, 06:11:49 pm
My mind fills with dread to begin to understand how captive hardware is being abused in such a way that it would be an ESD hazard.
 o.o

Tim
Title: Re: Nylon 6/6 screws cause ESD problems to components on PCB?
Post by: TimFox on July 13, 2022, 06:38:50 pm
He thinks that plain 6/6 Nylon screws will dissipate ESD.
Better to use brass.
Title: Re: Nylon 6/6 screws cause ESD problems to components on PCB?
Post by: thm_w on July 13, 2022, 08:06:16 pm
Quote from: TimFox on July 13, 2022, 06:38:50 pm
He thinks that plain 6/6 Nylon screws will dissipate ESD.
Better to use brass.

But in reality it wouldn't matter. Its just a standoff to support a PCB, that is likely electrically connected to the board below it.

Of course the information to determine this wasn't provided here, as usual.
Title: Re: Nylon 6/6 screws cause ESD problems to components on PCB?
Post by: TimFox on July 13, 2022, 08:41:23 pm
No, he just looked at the headline from a Google search and didn't read the data sheet.
Title: Re: Nylon 6/6 screws cause ESD problems to components on PCB?
Post by: ebastler on July 14, 2022, 02:52:09 pm
Quote from: Faringdon on July 13, 2022, 05:33:21 pm
..so i believe we will not inspire ESD problems to the components on the PCB just because of these Nylon 6/6 screws?

As long as you don't rub those Nylon screws with catskin, you should be alright I think.  ;)