There is no cure time like with a glue. when the solder cools below
liquidus it's done. (assuming eutectic solder) at any rate the joint is
finished when it comes out of the machine.  Of course, we're talking
electronic assembly here rather than mechanical joining.  the joint will
get a little stronger over a few days.  I think your test guys will
complain no matter what unless you clean or go to a lower solids flux.
now they complain that the flux is too hard to penetrate.  if you get
the boards to them while still hot they will complain of your sticky
flux getting all over the probes and mucking them up. no win! good luck
John Thorup

> -----Original Message-----
> From: Grant Emandien [SMTP:[log in to unmask]]
> Sent: Thursday, August 19, 1999 7:18 AM
> To:   [log in to unmask]
> Subject:      [TN] Solder joint curing
>
> Hi all out there,
>
> What is the average period for a solder joint (reflow and wave) to
> 'cure'? I
> also state that I don't quite know what cure means in this instant -
> but the
> general problem we have is the minimum period (if there is such a
> thing!)
> required for a solder joint to cure before introducing it to ICT under
> reasonable conditions of stability.
>
> Our test guys are complaining that the assemblies reach there machines
> too
> late (hours later), resulting in hardened flux which the test pins
> have
> difficulty in penetrating, causing damaged pins, retesting and hence
> unnecessary wear of the test fixtures and reduction in throughput.
> Introducing the assemblies too early while the joints are still in
> 'transition' may also result in retesting (true or false?).
>
> As you may have guessed, we don't clean boards as a norm however, this
> may
> be the way to go in future as will be experimenting with a cleaner
> shortly.
>
> Cheers
> Grant
>
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