PTHs that are 75% solder filled are not as strong against pin/lead pull-out than are those that are 100% filled. But pulling out of component leads is not a real reliability threat. In terms of functional reliability not much difference should be expected between 75% and 100% filled PTHs. Rework is another matter entirely. Every additional excursion to soldering temperatures is a threat to reliability, both short-term and long-term. Complete fractures can occur producing opens (in most cases intermittent at elevated temperatures) and failures right at manufacture; partial fractures will propagate during operational use thermal cycles to completion in the longer term. Particularly rework with its manual soldering operations are bad news, since manual soldering is in most cases the most severe thermal excursion in the whole manufacturing process (see Engelmaier, W., "Quality and Reliability Optimization Through Design for Reliability and Design for Manufacturability," Proc. Int. Electronics Packaging Conf. (IEPS), Austin, Texas, September 1996, pp. 81-93). Werner Engelmaier Engelmaier Associates, Inc. Electronic Packaging, Interconnection and Reliability Consulting 23 Gunther Street Mendham, NJ 07945 USA Phone & Fax: 201-543-2747 E-mail: [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************