Theminimum practical pitch for multi-lead components such as connectors is about1.27mm (0.050”); I have not personally dealt with any with smaller pitches. Itis in theory possible to do smaller pitches, but the required hole diameter,and thus the maximum lead size, becomes very small. Pad sizes are also severelylimited, which will affect soldering performance. The small hole alsorepresents a problem for getting flux penetration and hole fill.
The minimum pitch should not be different for Pb-free vs. SnPb. Ineither case, it is necessary to tightly control lead protrusion to reduceshorting risk. It is potentially more critical with Pb-free due to the highersolder surface tension.
Fritz's career in electronics manufacturing has included diverse engineering roles including PWB fabrication, thick film print & fire, SMT and wave/selective solder process engineering, and electronics materials development and marketing. Fritz's educational background is in mechanical engineering with an emphasis on materials science. Design of Experiments (DoE) techniques have been an area of independent study. Fritz has published over a dozen papers at various industry conferences.