Hi team - yep, I have seen very good HASL that had no solderability issues
and then as Ed detailed the "other stuff".  Knowing your board fabricator
and understanding his level of plating knowledge is a key parameter. I live
in a world with lots of resources so I can do the audits/assessments as
Richard detailed but if you don't, at least doing some level of due
diligence helps avoid big issues.

Dave

On Tue, Jan 23, 2018 at 10:10 AM, Ed Hare <[log in to unmask]> wrote:

> HASL … I’ve seen a lot of cases where rouge air knives and other factors
> cause thick and thin coating on the same pad.  The thin areas are exposed
> intermetallic which oxidizes and affects solderability.  Example (link <
> http://semlab.com/bad-hasl/>).
>
> ------------------------
> Ed Hare
> [log in to unmask]
>
>
>
>
> > On Jan 23, 2018, at 7:48 AM, rkondner <[log in to unmask]> wrote:
> >
> > Bev and John,
> >
> >  Thank you. So that is two votes for flatness issues.
> >
> >  Any others?
> >
> > Thanks,
> > Bob
> >
> >
> > On 1/23/2018 10:27 AM, John Burke wrote:
> >>
> >>
> >>
> >>
> >>              I believe this is referring to “random highs” where most
> of the pads are relatively flat but on some the solder is still on the pad
> typically high in the direction of the air knife
> >>
> >>
> >>
> >>              Sent from my iPad Pro
> >>
> >>
> >>
> >>
> >>
> >> On Tue, Jan 23, 2018 at 7:18 AM -0800, "BEV CHRISTIAN" <
> [log in to unmask]> wrote:
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Bob,
> >> Please explain what in your case you mean by “warts”.  Did you mean
> that literally or as you using the term as Wayne was?  HASL is by its
> nature is not flat.
> >>
> >> I would contend that HASL flatness CAN be an issue that solder paste is
> not always going to fix.
> >>
> >> Regards,
> >> Bev
> >> HDPUG
> >>
> >> Sent from Mail for Windows 10
> >>
> >> From: rkondner
> >> Sent: Tuesday, January 23, 2018 10:08 AM
> >> To: [log in to unmask]
> >> Subject: Re: [TN] soldering problems
> >>
> >> Hi,
> >>
> >> Can someone explain to me the warts associated with HASL? I know some
> >> would say flatness but since solder paste goes on all my boards that is
> >> not am issue.
> >>
> >> I am an EE and I typically run 5 to 25 boards for protos. A run of 100
> >> or 250 is a big job for me. I cannot keep up with validating every
> >> vendor. I cannot run and verify coupons for every run.
> >>
> >> HASL has been very good to me even with low cost vendors and simple
> >> board storage. What am I missing. (Other than soldering problems! :-)
> >>
> >> Thanks,
> >> Bob K.
> >>
> >>
> >> On 1/22/2018 7:25 PM, Wayne Showers wrote:
> >>> IAg is not a horrible idea for a surface finish, but it does come with
> its own warts.
> >>> 1) Creep Corrosion: DFR Solutions has done much research on this.
> Primary recommendation to mitigate it is to paste all component pads
> whether populated or not.
> >>>>> https://link.springer.com/article/10.1007/s11664-004-0025-x
> >>> 2) Move away from WS fluxes.  Because RMA fluxes utilize the Rosin as
> a suspension agent, you will get must less secondary issues with the flux
> penetrating into unwanted areas which include under the solder mask,
> between plating layers (This is critical for immersion silver as the silver
> immersion process creates micro-voids and micro-pitting of the underlying
> copper.)
> >>>
> >>> 3) Storage and Handling: Always wear clean cotton or latex gloves
> (preferred).  Cotton can trap oils and if the gloves are cleaned, many
> detergents and fabric softeners have phosphor and sulfur compounds in them.
> >>> And Silver saver paper is a must.  Silica desiccant and IAg are not
> compatible.
> >>>
> >>> And as a final aside, unfortunately the days of Tin-Lead are limited
> thanks to the tail wagging the dog over in the EU with Electronics as the
> target.  In 22 years of Electronics Manufacturing, I have had 4 issues with
> bad ENIG or ENEPIG plating, and Roughly 40-50 issues with flux penetration
> or entrapment including 1 recall that totaled over $1.5 Million Dollars.
> >>>
>