Mornin' Steve! Yep, solder dipping the connector sounds like a good idea, but I hope you have better luck than I did with my connectors. I still have some sitting in my office after I sent them out to see if they could be pre-tinned. Here's what I got back: http://stevezeva.homestead.com/files/Pre-tinning.jpg I called on two places; Corfin, which no-bid them, and Tintronics which gave it a go but didn't have any luck and resulted in what you see in the picture. My connector leads comes in two finishes, flash gold and matte tin, our customer doesn't want any pure tin finishes, so we were stuck with what we have. These are the kinds of parts that I've found it difficult to comply with the gold removal statement in the J-STD. I mean you could tin everything by hand and solder wick it off by hand, but is that practical? I know there's a statement in the standard that the requirement for gold removal may be eliminated if there is documented evidence that there are no gold related solder embrittlement issues associated with the soldering process being used. If you call Samtec and ask for that, they'll tell you; "We've not heard anything from any of our customers about solder embrittlement issues...", but to get that documented from them is another story. So we inform our customers that we're putting these down without removing the gold, and they tell us to continue on. So far so good. We've yet to hear of any embrittlement problems... Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Sauer, Steve (Xetron) Sent: Friday, April 11, 2008 5:55 AM To: [log in to unmask] Subject: Re: [TN] Samtec QMSS-DP Series Differential Pair Connectors Thanks for your insight Steve, as always! Yep, Samtec continually provides challenges for the simple man! I've taken steps to increase the apertures as you and GA Tan have suggested. The other attribute that needs correction is the soldermask webbing between the pads --> designer said it was easier to create a window around each set of pads --> which caused some gasketing issues. The other thing that I'm thinking about is having the leads hot solder dipped by Corfin Industries because we all know "nothing solders better than solder with Pb". As far as rework, if you don't have a bottom side heater, you're screwed. Thanks again. Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: Thursday, April 10, 2008 2:44 PM To: [log in to unmask] Subject: Re: [TN] Samtec QMSS-DP Series Differential Pair Connectors Hi Steve! Don't you just love Samtec connectors? Seems like they design a connector that looks good on paper, but more or less throw it over the wall when comes to manufacturing with it. We build some boards that use some Samtec connectors that are very similar, they're from the QTE series: http://www.samtec.com/ftppub/cpdf/QTE-XXX-XX-X-D-XXX-MKT.pdf These are a little longer than yours and I ran into the same issues...unsoldered pins. Here's a picture of the ones we put down: http://stevezeva.homestead.com/files/Samtec_QTE.jpg We put these on two assemblies, one has .062" thick PCB, the other has a .093". We have far more problems with the .062" thick board than we do with the thicker one...something to consider. I had the stencils re-made after we built the boards the first time because of the open solder joints. There's a bunch of 0402's on these boards so I'm using a .005" thick stencil. When I had the second stencil made, I had them open up the apertures for the connectors to 1-mil over in the X/Y dimension of the pads, And that seemed to help quite a bit. The overprint wicks back into the pad during reflow and gives a little more solder volume to help compensate for any coplanarity. One thing I can tell you is that these are a BEAR to rework! The thing that makes it tough is the grounding strip down the middle of the footprint. It can be done though. I have a Hakko FR-1012 IR preheater that I've had to use, and let me tell you I don't think I could have reworked one of these connectors without it. Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Sauer, Steve (Xetron) Sent: Wednesday, April 09, 2008 1:24 PM To: [log in to unmask] Subject: [TN] Samtec QMSS-DP Series Differential Pair Connectors Good Afternoon, Does anyone have any experience with the subject connectors? I'm currently evaluating these connectors (the mate is QFSS series) for a new application and am experiencing issues with coplanarity of the leads resulting in random nonsoldered pins. The coplanarity is listed on the spec sheet as .004" (.10mm) max and I'm using a 6mil stencil with 1:1 apertures (as recommended by the mfr). Thanks in advance for your assistance. Steve Steve Sauer, CEPM Sr. Project Engineer Northrop Grumman Xetron Cincinnati, OH 513-881-3368 [log in to unmask] --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------