Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


ESD protection

#20215

ESD protection | 4 June, 2002

We have "conductive" coats,shoes,floors,chairs and wriststraps. I want to get rid of the wriststraps, for the wires can ruin a product during touchup and hand-building SMD components on paste. My Question: when do we have enough ESD protection?? are shoes/coats/chairs/floors not enough?

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RDR

#20220

ESD protection | 4 June, 2002

A company I used to work for did not use wrist straps in some areas for the same reason. We had a conductive floor (not dissipative wax) and ESD shoes and heel straps that we tested three times a day. If you can ensure that feet are always on the floor and everything is at the same electrical potential you should be fine. To verify this I believe that 3M has what they call event detectors that you place on assemblies, components etc.. and they will tell you visually if that device was subject to ESD.

I am not an ESD expert but this may help.

Russ

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#20238

ESD protection | 5 June, 2002

thanks for the hint; i will go on searching for a way to prove that our protection is sufficient to customers/auditors

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#20241

ESD protection | 5 June, 2002

The issue is not the shoes, coats, straps, or doodangs. This issue is the voltage that the component / assembly 'sees'. * What voltages are you seeing in this work area? * What voltage will damage the components in this work area?

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Ken Bliss

#20414

ESD protection | 19 June, 2002

arzucom, have you considered using trays to handle your boards in process and your handbuilds. This method is fast becoming the industry standard method for a large variety of reasons, specifically ESD as when the boards are in the tray your people are handling the trays not the boards. The tray and mat in the tray is fully ESD "static dissipative" if you keep the trays in tray carts and the table tops on your techbenches are ESD safe you will virtually eliminate ESD problems. Obviously wrist straps are the best connection to be a commone ground, but many many customers have been through full ESD audits with out any problems and save money. For more info on tray carts see http://www.blissindustries.com also metro.com, and cari-all.com. Also see Bliss university on the Bliss Industries web site for additional ESD info. Hope that helps.

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Ken Bliss

#20415

ESD protection | 19 June, 2002

arzucom, have you considered using trays to handle your boards in process and your handbuilds. This method is fast becoming the industry standard method for a large variety of reasons, specifically ESD as when the boards are in the tray your people are handling the trays not the boards. The tray and mat in the tray is fully ESD "static dissipative" if you keep the trays in tray carts and the table tops on your techbenches are ESD safe you will virtually eliminate ESD problems. Obviously wrist straps are the best connection to be a commone ground, but many many customers have been through full ESD audits with out any problems and save money. For more info on tray carts see http://www.blissindustries.com also metro.com, and cari-all.com. Also see Bliss university on the Bliss Industries web site for additional ESD info. Hope that helps.

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#20423

ESD protection | 19 June, 2002

I worked for a place that built flight boxes for the military and some comercial. As Russ stated, wrist straps were used where they could be used. In areas where they were in the way, i.e. room where they masked and sprayed the boards, they had the special floor and operators used foot straps. Of course what ever device you were wearing was checked daily (wrist strap tester).

And yes, everything was bagged and put in a black 'Faraday Cage' box (sales pitch for Ken).

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