Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Press fit connnector



Press fit connnector | 9 February, 2000

Currently we have started seeing an issue around a scuzzy connector.The problem being that during insertion of this connnector a couple of pins refused to be inserted and as a result fold over, this folding of the pin is causing the pin itself to fracture just above the compliant section. This pcb has been in production for the past six months and the problem only arose a month ago. We are using a AEP-12T press, with a profile and tooling recommmended by the supplier,we have not changed the connnector or bareboard supplier.The problem is so inremittent that during extensive trials no trend was found. We have had cross-sections done and the hole size is within specification. My question is that although the hole size is within spec how important is the plating within the hole? Any information or advive would be gratefully appreciated. Currently stood around the machine scratching my head with the customer demanding answers.

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Re: Press fit connnector | 9 February, 2000

Sal: If it�s not the PCB, what about the connector itself ? Is it from a different production lot with some unregularities ( dimensions, tolerances, pin alignment, material weakness)? How about handling, storage, shipping causes ? Could it be a tooling problem (worn out tools)?

Similar things I�ve noticed only when the pin doesn�t hit the hole(misalignment).

Good luck


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Re: Press fit connnector | 9 February, 2000

Sal: Hey that customer standing around staring at you sound like fun, yeh right!!!

Wolfgang makes good sense, but, in addition, I�d like to drill-down on board fabrication (har har har) a little bit (har har har) more. You say the holes are the correct size.

� Is that the drill size? What�s the variation? Drills only get smaller with wear. � Is that finished size? What�s the variation? Finished size is a function of hole size, plating thickness, and solder coat thickness � lots of opportunities for stack variation to sneak-up and � If you spec anything, obviously finished size and plating thickness are critical. So, is the tolerance in the style of -0, + 0.010" or something like that? Rather than, good ol� �0.005". � How and where are these sizes measured? I�d be surprised if the opening wasn�t narrower at the board edges than the center of the hole. � Are the holes drilled perpendicular to the board surface?


Dave F

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Re: Press fit connnector | 10 February, 2000

The connectors are well within thier specification,and are also checked for misaligned and damaged pins , as regards the cross-section results, all holes are correctly aligned and are well spaced within their tolerance of +/-0.005 (a couple of isolated holes approx 0.003 out of line).Also measured alignmentof the ends of the connector legs (again outer rows), on one row, the worst casese were;one leg 0.005 out and one 0.008 out (both deviated to the centre)and on the other row the worst case was 0.006 out (deviated to the centre). All the holes have been measured with parallel pin gauges The AMP connector hole spec is 0.8 +/-0.08mm hole (0.0283 to 0.0346 inch)

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