Thanks Ed,
I was looking at 7.3.5.2 from that same document that declares
"Less than 180degree wetting" as a defect for Class 2 and
"Less than 270degree wetting" as a defect for Class 3.
The words say "lead to barrel wetting"
but pictures look like they are pointing to land wetting.
I would hate to be an inspector trying to evaluate that,
especially if I'm looking at a hole that is only 75% full
Jack
On Wed, Mar 16, 2016 at 4:36 PM, Ed Popielarski <[log in to unmask]>
wrote:
> IPC-A-610-F Table 7-4 Line C states: "Percentage of land area covered with
> wetted solder on solder destination side (see 7.3.5.3)" = 0% for all
> classes.
>
> Ed Popielarski
> Engineering Manager
>
>
> 970 NE 21st Ct.
> Oak Harbor, Wa. 98277
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>
> “It's one kind of victory to slay a beast, move a mountain, and
> cross a chasm, but it's another kind altogether to realize that the beast,
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> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
> Sent: Wednesday, March 16, 2016 2:25 PM
> To: [log in to unmask]
> Subject: Re: [TN] Hole Fill and Thermal Relief
>
> no, I'm not referring to vias.
> I'm trying to solder a connector into plated through-holes.
> IPC-A-600 7.3.5.1 allows a partial fill, see Figure 7-84
>
> In the next section
> IPC-A-600 7.3.5.2 requires wetting on the DESTINATION side which implies
> the hole is FULL of solder
>
> How can you have ANY destination side pad wetting on a PARTIALLY filled
> (but still ACCEPTABLE) hole?
> Those two seem incompatible, so I'm sure I'm misunderstanding.
>
> What's worse is Figure 7-91, which shows a solder joint not wetted to the
> lead.
> How could you ever know how far down the UNWETTED portion extends into the
> hole?
> (It IS labelled as a defect, I agree, but it still might be 75% wetted
> down the barrel) So you have a 360 degree wetted pad labelled as a defect
> because you can see the unwetted lead, but how can you APPROVE a 75% filled
> hole that you CAN'T see if it is wetted or not?
>
> Jack
>
>
>
>
>
> On Wed, Mar 16, 2016 at 2:57 PM, <[log in to unmask]> wrote:
>
> > you mean something like this?
> >
> > http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Module
> > s/XLamp/XLamp%20Application%20Notes/XLamp_PCB_Thermal.pdf
> >
> > filled via vs partially filled do have difference. you might need
> > x-ray inspection... my 1.4 cents.
> > jk
> > > Maybe I should know better than to ask two questions in the same
> > > email, but they're related...
> > > I got into a discussion about the hole fill requirement for some
> > > large through-hole power devices and connectors. The supplier is
> > > worried about using a "percentage" hole fill measurement, because he
> > > says that even if the hole is 75% full (or whatever percentage we
> > > want to use) the hole
> > wall
> > > will not be WETTED 75%. He maintains that the cold solder can extend
> > > up farther than the actual portion that makes a good joint. So he is
> > > looking at the TOP PAD WETTING for verification of a good solder
> > > joint, even though we don't require it.
> > >
> > > Q1) It seems like an inspection procedure looking for WETTING
> > > instead of HOLE FILL is not what is intended in IPC, but does he
> > > have a point? The hole fill problem is with Selective Soldering, not
> > > Reflow
> > >
> > > Q2) Wanting to provide bare board designs using good DFM practices,
> > > I would be willing to reduce my thermal spoke widths so the solder
> > > will flow better, but I can't find a calculation that would tell me
> > > what I need for something like 10A. There is nothing about this in
> > > the IPC-2152 Current Carrying standard. Is there a rough guideline I
> > > can use for current through planes using thermal relief??
> > >
> > > thanks
> > > Jack
> > >
> > >
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