My mom got me one of these for a birthday present. I looked inside and found a pointed screw, pointing to the inside of the internal chamber.
An infinitely small point on a surface can dissipate the accumulated charge, since the electrical field strength increases with the inverse of the radius of curvature. Unfortunately, enclosing this point inside of a conductive housing (I'm assuming the plastic is conductive) is putting the point inside of a Faraday cage, which is defined to have no internal field to dissipate.
I keep the device in my lunchbox to show people for a good laugh. I also like to show people my "ESD Safe" stainless steel tweezers that have a black conductive plastic coating. The conductive coating on the stainless steel must help dissipate the static . . .
Maybe we should change the topic of this thread to something more appropriate so we can all share the stupid things we see every day.
Later,
Carl
Carl B. Van Wormer, P.E., AE7GD
Senior Hardware Engineer
Cipher Engineering LLC
21195 NW Evergreen Pkwy Ste 209
Hillsboro, OR 97124-7167
503-617-7447x303
[log in to unmask] http://cipherengineering.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Wednesday, May 17, 2017 7:07 AM
To: [log in to unmask]
Subject: Re: [TN] IMC Formation Thickness in OSP
Hey Dean,
You liked those ROHS compliant foot straps so much, I know you'll just love the wireless wrist straps! At least they're only $4.00.
http://www.batteryspace.com/cordlesswriststrap--staticdissipativewithoutgroundingcord.aspx
Steve
On Wed, May 17, 2017 at 7:44 AM, Stadem, Richard D. < [log in to unmask]> wrote:
> I could not agree with you more, Dave!
> What a lot of people do not understand also is that IMC formation is
> self-limiting. Rework temperatures do NOT “double the thickness of the
> IMC and therefore reduces reliability by half” as one solder company’s
> PhD stated recently when attempting to sell low-melting –point solder alloys.
> IMC thickness normally has little effect on reliability.
>
> We in the electronics industry have to constantly beware of hucksters
> trying to make a buck with “easy” technical solutions, only to find
> you never get something for nothing, and sometimes you get nothing for
> something more, such as those green RoHS-compliant ESD footstraps for
> $49 per pair (still laughing and stepping down from soapbox also).
> Odin
>
> From: David Hillman [mailto:[log in to unmask]]
> Sent: Wednesday, May 17, 2017 8:21 AM
> To: Stadem, Richard D.
> Cc: TechNet E-Mail Forum
> Subject: Re: [TN] IMC Formation Thickness in OSP
>
> Hi Dean - good summary! There is currently a soldering iron
> manufacturer (who shall remain nameless) who is claiming their system
> manages the solder joint creation making the "ideal" IMC for a
> reliable joint. I have requested a copy of the data or research
> conducted on how the "ideal" IMC for solder joint integrity was
> derived and am still awaiting the information. I think we are causing
> some unnecessary waste of industry resources many times with the
> topic of IMC comes up. Ok, I'll get off my soap box!
>
> Dave
>
> On Wed, May 17, 2017 at 7:29 AM, Stadem, Richard D. <
> [log in to unmask]<mailto:[log in to unmask]>> wrote:
> Most IMC failures are actually design issues related to delta CTEs
> between components and substrates, and to varying degrees. I respect
> the challenge you have of summarizing the perfect storm of these
> design issues, alloy factors (including nucleation and brittleness),
> aging, and incorrect or abusive solder joint processes (including
> rework) that could contribute or lead to catastrophic SJ failure.
>
> And yet, we all manage to do this every day in this industry.
> Dean
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> Behalf Of David Hillman
> Sent: Wednesday, May 17, 2017 7:16 AM
> To: [log in to unmask]<mailto:[log in to unmask]>
> Subject: Re: [TN] IMC Formation Thickness in OSP
>
> Hi TechNet! I was holding off to see what folks posted. My question is
> "why does it matter?". An industry colleague and I are collaborating
> on a paper that covers "industry soldering myths" and intermetallic
> compound
> (IMC) failure is right at the top of the list. Its a true statement
> that IMCs are brittle but, as an industry, we seem to
> translate/proliferate that statement into a solder joint defect. There
> are very very very few industry reports/publications of solder joint
> integrity failures due to IMC in product use environments. There are
> tons of reports of IMC failures created because of grossly incorrect
> or abusive solder joint processes which isn't the same thing. Victor -
> my suggestion is to focus on having a correct soldering process using
> acceptable time/temperature parameters regardless if its the initial
> soldering process or a rework activity. If the solder process is
> correct, whatever the IMC thickness turns out to be, it will be acceptable.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]<mailto:david.hillman@rockwellcollins
> .com
> >
>
> On Tue, May 16, 2017 at 4:58 PM, George Wenger
> <[log in to unmask]< mailto:[log in to unmask]>>
> wrote:
>
> > Victor,
> >
> > I haven't seen and TechNetter responses but I'll give you my two cents.
> > The
> > IMC thickness numbers you heard sound much too high. I think the
> > IMC thickness should be half as thick as those numbers.
> >
> >
> > Regards,
> > George Wenger
> >
> >
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On
> Behalf Of
> > [log in to unmask]<mailto:[log in to unmask]>
> > Sent: Tuesday, May 16, 2017 8:35 AM
> > To: [log in to unmask]<mailto:[log in to unmask]>
> > Subject: [TN] IMC Formation Thickness in OSP
> >
> > Fellow TechNetters:
> >
> > What is the acceptable guideline for IMC Formation thickness on
> > OSP after
> > 2x rework.. IPC-4555 is still pending. I've heard of 3-5 microns on
> > first
> > pass and 5-10 microns on 2x RW. All comments/suggestions welcomed.
> >
> > Victor,
> >
>
>
--
Steve Gregory
Kimco Design and Manufacturing
Process Engineer
(208) 322-0500 Ext. -3133
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