Hello Peter. This has been an issue for many many years. As former chair of
the plated through hole fill task group, I can feel your frustration.

You need to define the hole to lead ratio for that particular component.
Typically if the lead is smaller than the hole by 0.010 the solder will have
a tendency to settle in the hole leaving depression around the lead. The
acceptance criteria talks about vertical fill and various levels of vertical
fill based upon the class of product being inspected. If the solder did
climb above the pth and wetted the top pad and settled then I consider this
complete filling of the hole and it should be acceptable for class 3
products. If it did not wet the pad due to weak knees, then the depression
is considered as part of the hole fill and must be considered when making
the acceptance or rejection decision.

How can you get the solder to stay up in the hole? The amount of heat the
solder joint is exposed to during the wave solder process can have an impact
on the amount of solder remaining in the hole. If the conveyor speed is too
slow, or the board goes to deep in the wave, or the angle of the product
leaving the wave is not correct, then all these things could impact the
amount of solder in the hole. Another side of the situation is if the solder
did not wet the barrel up to the top side. This can be due to not enough
heat from the soldering operation. Warped boards, fixtures, rails, inner
copper layer thickness, etc are all issues you must investigate.

I know this is only a few thoughts, but it is a start to make you ask some
questions and investigate the process.

Good luck and please keep us posted.


Leo Lambert

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Peter Crain
Sent: Monday, September 24, 2001 5:13 PM
To: [log in to unmask]
Subject: [TN] Insufficient solder


I need to nail down what an insufficient solder defect is. We are dealing
with through components.

We are seeing good solder fillets on the component side. But, there is a
concave dip 360 degrees around the lead of the secondary side of the
board. - (the solder doesn't fill completely to the top to be level with
the board.) There is a small fillet that goes around the lead 360 degrees.
This is not illistrated in IPC-A-610 wheater is it a defect. Would anyone
else consider this a defect?

Can anyone help clarify?

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