Jason:
What you are told is correct based on experience. Removing the tiles
makes sense but it is not absolutely necessary. A chunk of metal has a hard
time building a static charge. Probably it would be necessary to race it for
several blocks before it builds any voltage above 200 volts because it would
be distributed over the whole cart. On the other hand a piece of plastic
would charge 20 K volts over a small area and hold it for several minutes in
a heart beat.
Regards,
Ramon
> -----Original Message-----
> From: Wilson Jason [SMTP:[log in to unmask]]
> Sent: Thursday, October 02, 2003 9:14 AM
> To: [log in to unmask]
> Subject: Re: [TN] Bliss carts with non-ESD flooring
>
> Hi,
>
> Something I should have added in my initial post.
>
> The theory from the rep is. The cart itself is conductive. The cards
> sit in dissipative trays, with conductive (I think) mats. So any charge
> built up during transt stays on the cart, or on the card. Then the cart
> gets plugged into an ESD outlet (same as wrist straps). This will carry
> any built up charge from the cart to ground. Then when a grounded
> operator removes the cards, everything is grounded, and should not
> provide a chance for static damage.
>
> Does this sound resonable?
>
> The other concern that I have is someone releasing a charge build-up by
> being in close proximity (or even contact) with the cards while on an
> ungrounded rack or themselves not being grounded. This could be handled
> by proper training, but ESD procedures don't always seem to be followed
> to the letter of the law.
>
> Thanks,
> Jason
>
> Production Engineer
> Northrop Grumman Canada Corporation
> Halifax
>
> Box 960
> Enfield Postal Station
> 249 Aerotech Drive
> Enfield, Nova Scotia
> B2T 1K9
>
> TEl: (902) 873-2000 Extension 6564
> FAX: (902) 873-2174
>
> >>> "Marsico, James" <[log in to unmask]> 10/02/03 09:24AM >>>
> Sounds fishy... Walking on a non-ESD floor (vinyl?) will probably
> generate
> static electricity, which would be conducted from the "pusher" to the
> cart
> to the static sensitive hardware. I would think that you still would
> need
> to shield the hardware (ESD totes or bags) to prevent damage. The old
> faraday cage theory.
>
> Jim Marsico
> Senior Engineer
> Production Engineering
> EDO Electronics Systems Group
> [log in to unmask] <mailto:[log in to unmask]>
> 631-595-5879
>
>
> -----Original Message-----
> From: Jason Wilson [SMTP:[log in to unmask]]
> Sent: Thursday, October 02, 2003 7:44 AM
> To: [log in to unmask]
> Subject: [TN] Bliss carts with non-ESD flooring
>
> Hello Fellow Technetters,
>
> We are thinking of trying Bliss Industries carts for handling
> circuit cards
> in WIP. However, we do not have ESD flooring. According to
> the
> reps they
> can be used safely without ESD flooring, and without any cart
> sheilding.
>
> Does anyone out there use Bliss carts without an ESD floor? Can
> you
> let me
> know your experience with doing this?
>
> Thanks in advance for all help provided,
> Jason Wilson
>
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