Roger: I'll take a whack at this. > Esteemed Colleagues, > An engineer here wants to reject some SMD assemblies that were assembled > by > hand. I have reviewed the A-610, but it doesn't necessarily cover all the > problems we see. The product has been exhibiting random field failures, > and some are failing at temperature extremes (-20deg C or +70 to 85deg C). > To start with, what did you ask the CM to do? Build em' so they work or did you specify a workmanship requirement? > 1) Some pads are missing under a MQPF-144 device. "Former" pads with a > connection have the lead raised off the board and wire soldered from lead > to a via under the device. Some unconnected pads are missing and no > solder > joint is possible. Accept or reject? > Missing pads indicate either really bad circuit boards or a solder operator who is used to using a jackhammer. Unless you gave the CM the authority to perform "repairs" as opposed to "rework" I would reject them all. Again, it depends on what you specified. > 2) On same device, the wire fix for the removed pad raises the device so > that the leads had to be bent to the board and then soldered. Looks bad. > Accept or reject? > Anything that looks bad shouldn't be accepted. Anytime a lead needs to be bent out of the normal shape in order to make a connection is rejectable. But then again, what did you ask for? > 3) What are your thoughts about manual SMD assembly with fine pitch parts > down to 0.5mm for production? (By manual I mean manual part placement and > manual soldering.) > A couple of ways to handle this. Using a hot air tool is a bit more forgiving than hand soldering with an iron. However, I would only do this on a limited basis. For a "production" run, NO! > 4) What are your suggestions as to having our CM improve their soldering > techniques? > Obviously training. But more importantly, finding someone with the right touch. Even training can't make a watchmaker out of everyone. Identify those with the talent and go with them. Hope this helps. Good Luck. Bill Kasprzak Moog Inc., Electronic Assembly Engineering --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------