Hi Technos,

I'm in the middle of a crossfire here. Everybody, that is our QA and
customer's QA are concerned about one rework method we are using.
Because one particular connector is very capilarity prone, if we touch the
leads using liquid flux, the flux ends up on the golden contacts, giving
interconnection problems. I decided that we should touch the connector
without using any flux, except for the one inside the solder wire.

The problem is that QA is concerned about the reliability of a joint made
without flux. Is the heat enough to break the oxide crust? Will
intermetallics be there on both the pin and the pad?

My question is: is there any experimental data available on the degree of
oxidation on HASL surfaces in terms of time? After how long an exposure to
ambient conditions the oxide layer is thick enough to require flux for
removal?

Our boards are touched within, at most, 48 hours after reflow. Is this
timing long enough to ruin the solderability of the pad and the component?

Once again, some hard data is what I need, since I'm dealing with QA.

Thank you again for being there,

Ioan

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