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. > >>> >