Void
Historically we have treated the word "void" as as any 'isolated reduction of copper below the minimum specified.' (Paraphrased from IPC-6012 para.3.6.2.10). While the complete absense of copper indicates a different root cause than 'isolated reductions' (at the fabrication level), we might be opening up a Pandora's box by redefining it in any other way.

Fold
I think a picture of a fold is necessary to adequately describe a fold.  Boeing's BSPS-001 spec has a good depiction of folds.  Perhaps they could be enticed to share is for inclusion in T-50.

Pete


-----Original Message-----
From: John Perry [mailto:[log in to unmask]]
Sent: Monday, August 08, 2005 3:44 PM
To: [log in to unmask]
Subject: [IPC-600-6012] Request for Plating Definitions for IPC-T-50




Colleagues,



The IPC 2-30 Terms and Definitions Committee has requested that our
IPC-600-6012 groups assist them in the development of definitions for
the following terms relative to plated-through holes:



Plating Void

Plating Fold

Tangency (relative to Annular Ring)



We have been invited to the next T-50 teleconference which takes place
this Thursday, August 11th at 4PM Eastern, 1PM Pacific, for which the
dial-in number is 1-620-584-8200 and the passcode is 3366#.



There are currently no definitions for "Plating Fold" or "Tangency" in
IPC-T-50G.  "Plating Void", however, is defined as a void in IPC-T-50G
by the fact that the definition is simply a pointer to the term "Void".
This changes the potential definition of plating void from "an isolated
location where the plating thickness is less than minimum copper
thickness", as is often interpreted in the industry, to "the absence of
any substance in a localized area".



Mark Buechner, chair of the IPC-A-600 and IPC-6012 task groups,
recommends developing an IPC-T-50 definition of "Plating Void".  We
could also adopt the approach the military board specifications have
taken.



If you look at MIL-PRF-31032/1A, paragraph 3.6.4.1 you can see that they
have specified a dimension in the copper plating thickness that would
constitute a "plating void".



"Any copper plating thickness less than 80 percent of the specified
thickness shall be treated as a void."





If you are unable to attend the teleconference but would like to offer
input, please respond through this e-mail forum.



If you are planning to attend, we'd also be interested in any feedback
on proposed terminology for via protection in the forthcoming IPC-4761
user's guide:

Bumped Via Protection - Via protection where the hole plugging or fill
material protrudes above the surface of the hole interface producing a
convex shape.

Dimpled Via Protection - Via protection where the hole plugging or fill
material recedes below the hole interface producing a concave shape.

Planarized Via Protection - Via protection where the excess hole
plugging or fill material protruding above the hole interface has been
removed by a process to produce a coplanar surface.



Regards,



John Perry

Technical Project Manager

IPC

3000 Lakeside Drive # 309S

Bannockburn, IL 60015

[log in to unmask]

1-847-597-2818 (P)

1-847-615-7105 (F)

1-847-615-7100 (Main)