Brad,

These seem to fall inside the "pristine" area defined in the specification, which limits imperfections.  There does not seem to be guidance in the specification, and we should add something for that.

I would think this is currently being handled in a AABUS manner.

Certainly in the days of solder finish these may not have been discerned in the thicker solder.

Nick 



Nick Koop
Sr Field Application Engineer - Flex Technology
TTM Technologies - North America Business Unit
www.ttmtech.com

975 Parker Ave
Roseville, MN 55113
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Ph: 763-245-4825



-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Brad Toone
Sent: Thursday, May 22, 2014 4:53 PM
To: [log in to unmask]
Subject: [IPC-600-6012] Plating nodules on SMT pads

I have a question regarding plating nodules on SMT pads.  Searching through IPC 600 and 6012, the only place I can find anything regarding acceptance criteria for nodules is when it is mentioned in reference to thru holes and in reference to wire bond pads.  

IPC 6012 talks about defects on in a surface pad but only mentions "Defects such as nicks, dents and pin holes" in section 3.5.4.2.1 Rectangular Surface Mount Lands.  These are all void type defects, no mention of nodules.  

Any input on acceptability criteria of nodules on SMT pads?  Should IPC address this?  How would it be defined?  

Historically, we have accepted nodules up to .002 in tall and if they are not in a BGA area or on fine pitch components that we feel would be a solder risk.  I just want to see what others are doing.  See the attached for an example, the nodules in this case are .0013 tall.

Thanks,
Brad Toone
L-3 Communications CSW 


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