ESD info ???

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I have to do a online 'training' course because I'll being doing (basic)
servicing for x brand of printers (part swaping)

The ESD info they gave had in the course
"make the least possible movements with you body to prevent an increase
in static electricity from clothing fibre carpets"
(perhaps if i sat down, stayed very still  & just looked at the printer??)

""do not place the ESD-sensitive part on the printer cover or metal table..."
"..metal tables are electrical grounds. They increase the risk of damage.."
"if possible keep all ESD sensitive parts in grounded metal cabinet"

Is the above a bit of nonsense, ie the metal table & the contradtion with
using a metal cabinet.

Re: ESD info ???


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They obviously don't know what they are talking about.
Proper ESD technique goes something like this:
1) Only work on equipment at an approved ESD handling station (grounded
mat at the very least)
2) Wear a wrist strap to dissipate your body to ground
3) Only use anti-static or conductive bags, bins, trays etc within the
ESD safe area.
4) Transport all items in ESD-safe bages AND conductive boxes.
5) Wear anti-stat coat if there is a chance of clothing coming in
contact with the ESD sensitive item.

There are various levels and techniques above this, but that's a
general situation.

One of the biggest misunderstandings is that "anti-static" bags and IC
tubes protect a device from damage - they don't. Only static-shielding
or conductive materials can do that. That is why when you get an IC
from Farnell it comes in its anti-staic tube (or whater) inside a
conductive bag.

Dave :)


Re: ESD info ???



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They did include some of the (sensible) points you mention
but no mention of ESD station
no mention of antistatic coat: synthetic clothing  is a nono (not to mention
nylon carpet)
the metal table comment didnt really make sense: whats the diff between a
metal table & metal cabinet


Re: ESD info ???




SNIP
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What????

See http://www.ece.rochester.edu/~jones/demos/shielding.html

It is demonstrable that a sensitive electronic device placed inside a
shielding bag is impervious to an external electrostatic charge.

Re: ESD info ???


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Thats what he said.
"That is why when you get an IC from Farnell it comes in its anti-staic tube
(or whater) inside a conductive bag."



Re: ESD info ???


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Yes, that's what I said. A "static shielding" bag will protect a device
when in transit and storage. In fact a static sentive device must
*only* be transported in a "static shielding" bag.
A "static shielding" bag is different to an "anti-static" bag (the
common cheap "pink" bags, and pink bubble wrap). Anti-static bags do
not protect a device from an external static charge, they simply
prevent the build up of static when used within an ESD safe
environment.
Most IC tubes are also only "anti-static" and not "static shielding" so
therefore provide little protection to static discharge.

A bag must specifically state "static shielding" in order for a device
to be protected. If is just says "anti-static" then it's pretty much
useless outside of an ESD safe area.

This is the first thing you'll get a practical demo of when you do a
certified ESD course.

My former company actually failed Farnell on an ESD audit one time, and
we couldn't order anything from them for months until they fixed
whatever trival problem it was. ESD can be serious business.

Dave :)


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Sorry for my confusion David...

When I was using "anti-static" bags prolifically the only type
available was the metallised "shielding" bag. The pink poly and
bubble-wrap types were either not available and/or not recommended so
I hadn't come across them until relatively recently and so they didn't
occur to me as being the types you were talking about. Since your
original reply didn't specifically mention the pink poly and b/w bags
I thought you were referring to metallised shielding bags.

Looking at this page
http://www.esdjournal.com/techpapr/ryne/esdbags.htm it seems that the
problem with the pink poly and bubble wrap types is that they dry out
with age and can themselves become generators of huge static charges.
The b/w type relies upon air gap spacing to prevent static discharges
from getting to the contents so it doesn't actually provide
(conductive) "shielding" at all (as you correctly stated).


Re: ESD info ???



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I remenber my boss demonstrating to me that the 'pink' bags/foam/bubblewrap
arent to be used.
He rubbed the bag up & down the bench & few times & built up enougth static
for the bag to stick to the wall.

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