Questions: 1. Does pulling of the connector tell me anything about the inner-metallic bond between the lead and pad? No info here, you'd need to use a stud puller or tensile strength tester on test coupons or rigs to get any meaningful data on bond strength. 2. Is this a fair way to determine the bond? As above no. 3. Because the left over joint looked porous, does this mean the solder did not flow completely? Or, did the pulling of the lead away from the pad cause the porous look? Reflowed solder does look porous if ripped apart, tin lead solder joints will have voids in them anything from 0% (in reality 5%) - 15% by volume. If the solder (paste) doesn't reflow properly the give away is; a. the individual solder particles may be seen without necessarily resorting to magnification b. the solder will not have wetted up the joint. (these aren't drop dead certs, but are useful pointers that something isn't right) Best of luck, Andrew Hoggan BBA Associates Ltd www.bba-associates.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of West, Jim Sent: 24 August 2001 20:09 To: [log in to unmask] Subject: [TN] Determining the Inner metallic bond on a surface mount connector Hi, I had Steve put a picture on his web-site. Go to: <http://stevezeva.homestead.com/> Labeled "Connector footprint" Sorry for the picture not being a closer look. Hopefully you'll understand. In this picture, you will see the leftovers of me removing a 41 position connector with pliers. What I was trying to do was see what kind of solder connection I had. I wasn't sure what was going to happen when doing this, but what you see in the picture is that most of the pads came away from the substrate with the connector leads, and 14 positions had solder left behind that looked porous. Before I removed the connector, all 41 positions had evidence of wetting from the pad up the sides of the leads. I had some doubt of the joint because the solder did not show as good of a wetting action between the pad and the toe of the lead (by the way, this is a gull-wing style). We use IPC class II inspection criteria. This same board passed our electrical continuity test. Questions: 1. Does pulling of the connector tell me anything about the inner-metallic bond between the lead and pad? 2. Is this a fair way to determine the bond? 3. Because the left over joint looked porous, does this mean the solder did not flow completely? Or, did the pulling of the lead away from the pad cause the porous look? I'm just trying to determine if I have a good joint, but we don't have any way of verifying the joint except by using the IPC guidelines. Thanks for your help! Jim ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------