I've taken electrostatic field readings after blowing dry nitrogen on
various board substrates, at various pressures and under different
conditions of relative humidity, and never found any appreciable charging.

Because de-ionizing nozzles are available, our customers seem to raise this
issue with some frequency.  What I've found useful is to document my
findings in a project memo that I can pull out and display when challenged.

By the way, I don't think that grounding the nozzle has any appreciable
effect.  If the wire running down the hose is a nuisance, try disconnecting
it when you take the readings with your electrostatic field meter.

> ----------
> From:         [log in to unmask][SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;[log in to unmask]
> Sent:         Monday, August 28, 2000 10:41 AM
> To:   [log in to unmask]
> Subject:      [TN] Another ESD question
>
> How do you folks feel about using compressed nitrogen to dry printed
> circuit
> boards? One of our customers will not allow aqueous cleaning of their
> hardware.
> As a result we clean all of their hardware in alcohol and dry by blowing
> it off
> with compressed nitrogen with the regulator at about 100 PSI. The nozzle
> is
> grounded at the tip. Please note that this is not related to my earlier
> quetion
> as this is done in a different area and only used on our space flight
> hardware.
> Thanks again,
> Charles Caswell
>
> ##############################################################
> TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
> ##############################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in
> the body:
> To subscribe:   SUBSCRIBE TECHNET <your full name>
> To unsubscribe:   SIGNOFF TECHNET
> ##############################################################
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
> additional
> information.
> If you need assistance - contact Keach Sasamori at [log in to unmask] or
> 847-509-9700 ext.5315
> ##############################################################
>

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################