Was workbench likely to have been ESD safe? (no ESD mat) - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: June 06, 2020, 03:53:29 pm
content: 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.uk/media/wysiwyg/infographics/workbenches/QMP-ESD-Industrial-Workbench-Data-Sheet.pdfDo 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.

author: ocset
author_rank: Super Contributor
timestamp: June 06, 2020, 05:17:52 pm
content: ....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.He buys in all/most his electronics from china, and doesnt know electronics that well.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.

author: SMTech
author_rank: Frequent Contributor
timestamp: June 06, 2020, 05:21:53 pm
content: Yes, we have Technibench ones . Quite often we'll have mats on top for physical protection especially from rework, still have the odd bench with burn holes or drill marks in it tho'.

author: pisoiu
author_rank: Regular Contributor
timestamp: June 06, 2020, 06:48:59 pm
content: Table with ESD mat is enough only if you wear wrist conductive band, connected to ground and you do not touch anything without having that wrist band. Otherwise, floor must also be conductive, grounded AND you have to use foot grounder (heel strap, etc)

author: ocset
author_rank: Super Contributor
timestamp: June 06, 2020, 11:11:09 pm
content: QuoteThanks, i see Technibench offer a Florite laminate, which is said to have a resistance from 100kR to 10MEGOhms....the thing is, does that mean that at any point on the laminate, the resistance to earth ground is 10^5-10^7 ohms, or does it mean that thats the resistance per unit square?....or is that the resistance "along it", or "through it"I believe an dissipative ESD mat with poppers and connected to earth ground via the poppers would offer better than 10^5 to 10^7 ohms to earth at any point on it.I dont see how a laminate which hasnt actually got ESD poppers on it can really have a <35 Megohms resistance to earth ground.The technibench (as well as all other such "ESD bench") datasheet simply doesnt give a potential buyer enough details to assess the difference between a technibench surface and an ESD mat.

author: SMTech
author_rank: Frequent Contributor
timestamp: June 07, 2020, 05:02:15 pm
content: I understand you don't like the datasheets but do you really think widely used & manufactured industry specific furniture is truly not fit for purpose?There are studs on the Technibenches both on the top surface and on the frame. Of course nothing works in isolation so you do need to connect the tables to ground either with conductive feet to a suitably treated floor or with cabling, or both, wear wrist straps, have ESD chairs, test frequently and clean frequently.

author: ocset
author_rank: Super Contributor
timestamp: June 07, 2020, 08:17:00 pm
content: I think these professional ESD benches are likely better than eg wooden benches.....but in the link in the top post, it actually shows an esd mat being used on top of the bench.....i think this demo's that the bench surface isnt fully up to it.