What those tables state are;
The wrap plating thickness (beginning at the hole wall plating extending
.984 mils away from the hole edge) on the foil (or flashed) plated surface.
Plating shall be continuous and not less than .472 mils from the hole edge
to past .984 mils on the surface.
I would caution using or applying the term "overhang" as that often means
one plated area ending, another beginning (i.e. button plating perhaps).
Wrap plating is not overhang, overhang in some instances is cause for
rejection.
The intent here is to have a "continuous" amount of plated copper from
within the hole wall extending onto the surface which will provide a very
robust connection (after additional plating i.e. pattern or panel plate)
between the via and surface features (i.e. pads, traces, etc).
Franklin
-----Original Message-----
From: Dave Seymour [mailto:[log in to unmask]]
Sent: Thursday, January 24, 2008 4:30 PM
To: TechNet E-Mail Forum; Franklin Asbell
Subject: Re: [TN] ipc-6012B amendement
I talked to my board house about this.
I believe the source of confusion is one of spec terminology.
In figure 3-13 the words " Minimum Wrap " are used to describe
the copper coming back away from the barrel wall. Shown as 25um.
For lack of a better term I used the word "overhang ".
In table 3-2, the same words " Minimum Wrap " are used to describe the
thickness of the wrap. Shown in Figure 3-13 as "Minimum Copper Thickness"
An improvement to table 3-2 would be to use the same words in both places.
For example Table 3-2 "Minimum Wrap " could be changed to read
"Minimum Wrap Copper Thickness".
Thanks
Dave
Franklin Asbell wrote:
>Look again at Table 3.2, under code C.
>
>Under section C where it says Minimum Wrap (right below Copper - minimum
>average, and Minimum thinc areas). For class 3 the minimum wrap would be
>.472 mils thickness extending from the hole edge outward .984 mils.
>
>Not sure where you are getting overhang from?
>
>Franklin
>
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Dave Seymour
>Sent: Thursday, January 24, 2008 3:28 PM
>To: [log in to unmask]
>Subject: [TN] ipc-6012B amendement
>
>Howdy,
>
>Section 3.6.2.11.1 of the 6012 amendment Dec 2006 talks about
>the Minimum Wrap on a via filled hole.
>
>In Diagram 3-13 there is a measurement labeled "Minimum Copper Thickness",
>which is shown as the thickness of the Wrap.
>
>Where is the table that shows the "Minimum Copper Thickness" by Class?
>
>Table 3-2 only talks about the amount of the overhang of the wrap, not the
>thickness as such. Table 3-2 has something called Min Thin areas, but this
>is not labeled in the diagram 3-13.
>
>Am I missing something?
>
>Thanks
>Dave
>
>
>
>
>
--
Dave Seymour, CID+
Catapult Communications Inc.
800 Perimeter Park Dr, Suite A
Morrisville, NC 27560
Direct: (919)653-4249
Main: (919)653-4180
Fax: (919)653-4297
[log in to unmask]
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