Werner

Sorry to take you to task but I'm 99.999% sure that both ISO 35 and ISO 2000 specs give
g as the international and official abbreviation for grams.  The American Standard
Abbreviations for Scientific and Engineering Terms says likewise, as does the National
Bureau of Standards Publication 233. In all cases, the gravitational constant is
defined as 980.621 cm.sec-2, without an abbreviation. In any case, the rms should be a
subscript, but is not necessary, because it is the standard energy level of an
alternating component.

Brian

Werner Engelmaier wrote:

> Hi Ingemar,
> I sure hpe it says 6-10 grms, not grams. If it says grams than the document
> got over-edited by staff thinking this is a typo. grms stands for 'g', the
> Earth gravitational acceleration constant and rms stands for
> root-mean-square, and is standard vibration terminology.
> This is an effective ESS procedure for finding solder joints with latent
> defects, and comes from some of the old military vibrational requirements.
> The full details you would have to get from one of the vibration gurus, I am
> not one of them.
> In addition, be careful with superBGAs, they warp at high power dissipation
> and can cause tension induced SJ failures.
>
> Werner Engelmaier
>
> ##############################################################
> TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d
> ##############################################################
> 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 1.8d
##############################################################
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
##############################################################