Because a whole BUNCH of REALLY smart people sat in a room for MANY MANY hours at a time over many years to develop and document acceptable solder joint inspection criteria, based on real world experiences and testing.  That document is called IPC-A-610.  And it, my friends, says thou shalt not have ANY end overhang of a chip component (ref IPC-A-610E section 8.3.2.2).  This is for even Class 1 product (Teddy Ruxpin's and Xbox's).   And, btw, a partial listing of that group of super-smart people is listed right at the front of the document, from all sorts of industry leading, highly successful companies.

Just my 2 cents.

What are the contractual obligations for acceptance criteria?

Another option is to turn the tables.  IPC-610 brings evidence this is NOT acceptable.  Make them PROVE it if they think it is.


-----Original Message-----
From: Pete [mailto:[log in to unmask]] 
Sent: Thursday, March 21, 2013 9:41 AM
To: [log in to unmask]
Subject: [TN] Explaining why pretty solder joints arn't good solder joints

We have a product on which the assembly vendor decided to change the power inductor we specified.  The part they used is close to the same size, but even at nominal, the leads overhand the pads on 3 sides under the body.  I raised a concern that these stress points create a risky solder joint.  The engineering group running this project keeps sending me pictures:  "look - it fits on the board and they got solder on the outside of the leads!"  I pointed out that the 3 sides of the joint they can't see are stress points.  Any tips on explaining the risk here?

Pete

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