Let's hope this doesn't happen!  Connectors are typically tested for
"durability cycles" per the application.  These durability cycles can number
25 (tin plated), 500 (typical PC), 10,000 (PCMCIA) or even 100,000 (Smart
cards).  Even though the system may never see these numbers, the "spring"
member must be designed to handle the respective number of cycles the
application or specification requires. The risk is losing normal force which
increases resistance which could lead to failures.

Martha Rupert
AMP Incorporated
email:[log in to unmask]


> -----Original Message-----
> From: Haugaard Svend [SMTP:[log in to unmask]]
> Sent: Monday, June 29, 1998 2:43 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] HELP: Cracking Discretes on PCB's
>
> SMT connectors are just as reliable as leaded connectors. If your former
> leaded connector did the job without cracking it's most likely that a
> similar SMT connector also will do the job.
>
> Flexing a PCB will most certainly stress the solder joints regardles of
> lead or SMT. Lots of books and articles exist concerning this matter but
> be sure that it might take some time to get an overview of this. Just
> try searching at the web ...
>
> I think there must be a kind of mechanically support to the connector in
> order to avoid any load to the solder joints - regardles of connector
> type. In this way stress will never arise at the solder joints.
> Testing this could e.g. be by means of plugging/unplugging many times to
> simulate life cycle - most likely the connector wears out and thus the
> press-in force reduces.
>
> Best regards
> Svend
>
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