Re below: SM  [component attach] adhesive is very suitable for hole
plugging, application/cure characteristics etc just right.

Mike Fenner

----- Original Message -----
From: "Carano,Michael" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, September 28, 2000 4:12 PM
Subject: Re: [TN] Solder in via holes after HASL process


> > Dear Jacob,
>
> You can use a via hole fill process. In this instance, plug the vias
with an
> epoxy material. This should prevent solder from getting into the
holes that
> are not desired. If plugging both sides of the via is acceptable
with the
> end user, this could be a solution.
>
> Best regards,
>
> Mike
>
> -----Original Message-----
> From: <Jacob Pao King Hing> [mailto:[log in to unmask]]
> Sent: Thursday, September 28, 2000 7:10 AM
> To: [log in to unmask]
> Subject: Re: [TN] Solder in via holes after HASL process
> Importance: High
>
> Franklin,
> I believe you may misunderstood my problem.
> The solder in the via holes is actually residues from the HASL
process. So,
> during the IR reflow, it came out (via holes facing downward) & form
solder
> lump at the annular ring of the via holes. It's not total disaster
but a
> pain in the ass for assembly house.
> As I see it, most of the affected via holes are those below 22 mil
(hole
> size). Is there any limitation for the air knife to totally clear
off the
> excessive solder?
> My understanding from one of our customer's spec did indeed specify
that
> solder in via holes <22mil is allowed. Other than this spec, what's
the
> common practice by

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