It could be a Cu wire bond to a power chip, although I may be reading more
into Victor's description than he intended.  In that case I would expect
signs of thermal overstress, or mechanical necking, etc. unless it was
strictly related to vibration or over-bonding (as in neck/heel breaks).

Could be the result of ultrasonic cleaning if the cleaner operates at the
wrong or fixed frequency

Just say'in

Steve C

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Friday, April 10, 2015 4:26 PM
To: [log in to unmask]
Subject: Re: [TN] Copper wire open

38G solid core? Sure, but you need to work harden it by bending it back and
forth. Also, if someone's iron runs hot, the wire dissolves into the solder
in about 10 secs, so it is easy to thin it below 4 mils without noticing.
38G nickel is much more robust if you're looking for something which stands
up to abuse.

Wayne

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Victor Hernandez
Sent: Friday, April 10, 2015 11:45 AM
To: [log in to unmask]
Subject: [TN] Copper wire open

Fellow TechNetters:

   Is it possible for a 4 mil diameter copper wire open without any apparent
signs of elongation, mechanical stress?   Can the copper wire snap cleaning
at the grain boundary?

Victor,


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