Yea, when you get enough co-deposited organics to make a surface finish pretty, lots of other "strange issues" begin to happen during the soldering process. Dave On Fri, Mar 6, 2015 at 11:01 AM, Stadem, Richard D. < [log in to unmask]> wrote: > That is what I suspected, that it had to be temperature related. Weird > stuff. > > > > *From:* David Hillman [mailto:[log in to unmask]] > *Sent:* Friday, March 06, 2015 10:30 AM > *To:* TechNet E-Mail Forum; Stadem, Richard D. > *Subject:* Re: [TN] bright electroplated tin, versus immersion matte tin > > > > My guess is that those pins are ground pin so they didn't reach the same > temperatures as the other pins which are probably signal pins. Lower > temperature means less propensity to volatilize the co-deposited organics. > > > > Dave > > > > On Fri, Mar 6, 2015 at 9:41 AM, Stadem, Richard D. < > [log in to unmask]> wrote: > > Just curious. Why did the two pins in the middle of the picture not > display that condition also? The answer to that question would point to a > mitigation strategy. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory > Sent: Friday, March 06, 2015 9:38 AM > To: [log in to unmask] > Subject: Re: [TN] bright electroplated tin, versus immersion matte tin > > Hi Dave! > > Ahh yes, remember a while back when I was working in Tulsa the time I had > issues with a AMP Densipac connector that I had posted about that you > answered for me? You were thinking that it was bright tin. Below are the > photos and the email thread... > > Steve > > http://stevezeva.homestead.com/files/AMP_Connectors.jpg > > http://stevezeva.homestead.com/files/Connector_Blumpies.jpg > > ******************************************************** > > Steve Gregory <[log in to unmask] > < > http://listserv.ipc.org/scripts/wa.exe?LOGON=A3%3Dind0906%26L%3DTECHNET%26E%3Dquoted-printable%26P%3D4384754%26B%3D--%26T%3Dtext%252Fplain%3B%2520charset%3Dus-ascii%26header%3D1 > >> > Sent by: TechNet <[log in to unmask] > < > http://listserv.ipc.org/scripts/wa.exe?LOGON=A3%3Dind0906%26L%3DTECHNET%26E%3Dquoted-printable%26P%3D4384754%26B%3D--%26T%3Dtext%252Fplain%3B%2520charset%3Dus-ascii%26header%3D1 > >> > 06/23/2009 06:49 AM > Please respond to TechNet E-Mail Forum <[log in to unmask] < > http://listserv.ipc.org/scripts/wa.exe?LOGON=A3%3Dind0906%26L%3DTECHNET%26E%3Dquoted-printable%26P%3D4384754%26B%3D--%26T%3Dtext%252Fplain%3B%2520charset%3Dus-ascii%26header%3D1 > >>; > > Please respond to Steve Gregory <[log in to unmask] < > http://listserv.ipc.org/scripts/wa.exe?LOGON=A3%3Dind0906%26L%3DTECHNET%26E%3Dquoted-printable%26P%3D4384754%26B%3D--%26T%3Dtext%252Fplain%3B%2520charset%3Dus-ascii%26header%3D1 > >> > > > Subject [TN] "Blumpie" looking connector leads... > > Morning all! > > Trying to stay cool here! Broke 100 degrees yesterday and Sunday, and it's > probably going to break 100 degrees today. Summer has come with a > vengeance! Ran across something yesterday that I've never seen before. We > build a board that uses this AMP Densipac SMT connector. We've built a lot > of these boards before without any issues at all. This latest run we have > something going on with these particular connectors. > > Here's a photo of them on the PCB: > http://stevezeva.homestead.com/files/AMP_Connectors.jpg You can probably > see that the leads have this "Blumpie" look to them...both bumpy and lumpy. > This is fresh out of the reflow oven. Here's a closer look: > http://stevezeva.homestead.com/files/Connector_Blumpies.jpg > > If you notice the two pins either side of the white line look fine. They > are the anchor pins that are for mechanical strength for the > connector...they are not I/O pins. The rest of the board looks absolutely > fine too. Not a bit of problem. It's just the I/O pins. We have noticed > that connectors with certain date codes don't have this problem. Also, > before reflow the connectors look okay. Luckily we've only built a few > boards, and we're stopping until we can get to the bottom of this... Have > any of you ever seen "blumpie" connectors like these before? > > Steve > > ********************************************************* > > From: [log in to unmask] > < > http://listserv.ipc.org/scripts/wa.exe?LOGON=A3%3Dind0906%26L%3DTECHNET%26E%3Dquoted-printable%26P%3D4384754%26B%3D--%26T%3Dtext%252Fplain%3B%2520charset%3Dus-ascii%26header%3D1 > > > [mailto:[log in to unmask] > Sent: Tuesday, June 23, 2009 7:22 AM > To: TechNet E-Mail Forum; Steve Gregory Cc: [log in to unmask] < > http://listserv.ipc.org/scripts/wa.exe?LOGON=A3%3Dind0906%26L%3DTECHNET%26E%3Dquoted-printable%26P%3D4384754%26B%3D--%26T%3Dtext%252Fplain%3B%2520charset%3Dus-ascii%26header%3D1 > > > > Subject: Re: [TN] "Blumpie" looking connector leads... > > Hi Steve - ah, the beauty of being a materials engineer is that the > industry doesn't seem to learn from past material mistakes so I really > don't need to learn anything new! I recommend you check with your connector > vendor to confirm that the connector surface plating is bright acid tin. > The photos appear to show a bright acid tin surface finish that has > blistered during the solder reflow process due to excessive co-deposited > organic material. Bright acid tin finishes (plated correctly) look very > nice but have terrible solderability characteristics and are a known tin > whisker generation source. It appears that you may have had a surface > plating change from what you normally had been procuring. Good luck. > > Dave Hillman > Rockwell Collins > > > > On Thu, Mar 5, 2015 at 9:01 PM, David Hillman < > [log in to unmask]> wrote: > > > Hi Guy - ok, here is the short list and yes, I have a HUGE dislike for > > brite acid tin: > > > > Brite acid tin (electroplated) > > 1) grows tin whiskers like a chia pet due to the co-deposited organics > > in the plating. The same co-deposited organics "boil" during a > > soldering process causing lots of voids and generally poor solder > > joints. Very short shelf life - three months is not uncommon. Doug and > > I have some great pictures of the bubbling in one of our tutorials > > > > Matte tin (electroplated) > > 1) one of the most common component finishes on components today. > > Lacks thermal excursion robustness but will pass JSTD-002/003 > > solderability testing from good plating processes. Can also tin > > whisker, less prone than brite acid tin, but also not zero tin > > whiskers. Good for corrosion issues in some product use environments. > > Fewer soldering ability issues with stronger fluxes > > > > Immersion tin > > 1) Has poor thermal excursion robustness but will pass JSTD-003 > > solderability testing. Much less propensity to tin whisker when > > plating formulation includes specific inhibitors. Good for corrosion > > issues in some product use environments. Very flat and good for SMT > > assembly. Because it is deposited by a galvanic reaction, typical much > > thinner than electroplated tin systems. This plating system is covered > > by the IPC-4554 specification. > > > > Take a look in the IPC AJ 820 or the IPC -7095 standards as they both > > have good sections on surface finishes including some tin plating > comparisons. > > And remember, the initiation of tin whiskers is a characteristic of > > tin itself so all pure tin finishes, regardless of their deposition > > process, can have tin whisker issues. Hope this helps. > > > > Dave Hillman > > Rockwell Collins > > [log in to unmask] > > > > On Thu, Mar 5, 2015 at 7:51 PM, Guy Ramsey <[log in to unmask]> wrote: > > > > > Can anyone give me a nutshell difference between immersion tin for a > > solder > > > finish and electroplated tin? > > > Advantages, disadvantages as a surface finish more than the chemical > > > and plating process differences. > > > Thanks, > > > Guy > > > > > > > > > > > > > > > > > > ____________________________________________________________________ > > > __ This email has been scanned by the Symantec Email Security.cloud > > > service. > > > For more information please contact helpdesk at x2960 or > > [log in to unmask] > > > ____________________________________________________________________ > > > __ > > > > > > > > > ______________________________________________________________________ > > This email has been scanned by the Symantec Email Security.cloud service. > > For more information please contact helpdesk at x2960 or > > [log in to unmask] > > ______________________________________________________________________ > > > > -- > > > This email and any attachments are only for use by the intended > recipient(s) and may contain legally privileged, confidential, proprietary > or otherwise private information. 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