A multimeter will not give you correct readings.  You need a megohm meter to
conduct surface resistively testing.  ANSI/EOS/ESD S11.11-1993 is the test
method standard.  Surface Resistance is not the measure that you really
need. It is the triboelectric charge generation of the brush that you are
really concerned with. They are not directly related. Refer to ESD Adv 11.2
"Triboelectric charge Accumulation Testing" for guidance. I would test the
brushes to determine if a charge is generated and if they remain on the
brush or dissipate rapidly. The sensitivity of your devices is the
determining factor on what you require for maximum charge generation.

Al Cash



-----Original Message-----
From: Christopher Murphy [mailto:[log in to unmask]]
Sent: Saturday, August 12, 2000 3:21 PM
To: [log in to unmask]
Subject: Re: [TN] ESD question


Jason,

I asked this question on the Technet a few months ago and the consensus at
the time
appeared to be that a metal / wooden handled natural horsehair brush would
not generate
static charges and was the most cost effective solution.  I tried out a
number of
different 'ESD' safe type brushes, but they were very expensive and I
couldnt get any
resistance readings off 2 of the brushes.

We continue to use horsehair brushes with no apparent adverse effects on our
products.

Maybe it would be a different story if you had some really ESD sensitive
components on
your boards.

Here is a question from an ignorant Production Engineer (myself) - How do
you measure
the 'static disspative' property of a material?  I use my multimeter set to
200mega
ohms, which seems to work for most materials, but other materials I get no
reading.  Is
a multimeter the correct way of doing this?

Regards,

Chris Murphy

"Jason Larson, AScT" wrote:

> Hi Technet, question about use of brushes and ESD
>
> We need a brush to remove lead clippings from the backside of the board,
> seem to stick between FET leads when operators put the boards down on the
> table.
>
> Is there a material of choice for brushes?
>
> Thanks,
>
> Jason Larson
>
> ##############################################################
> 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
##############################################################

##############################################################
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
##############################################################