Hi Jerry,
>Recently, the question has been raised whether the actual hole size vs. lead
>diameter has anything to do with regards to quality and longevity of the
>joint on high power components.
>Would more or less solder around the lead increase or decrease the joint
>quality and reliability?
It would not impact quality, but it more solder may increase reliability if
the threat to reliability comes from a vertical lead movement for whatever
reason.
>Is there a formula that would describe min/max hole size with respect to the
>lead diameter in terms of best solderability and longevity of the joint?
No, neither for solderability nor longevity.
>Would the power being dissipated by the component had any effect on that
>formula?
Yes, if the vertical lead movement results from a differential thermal
expansion that is affected by the component temperature.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask], Website: www.engelmaier.com

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