Pb-free alloys can shorten tip life – but so can poor practice.

During the introduction of Pb-free, solder iron tip damage was very common due to the variability of the plating on some tips. Damage also has been caused by poor control and incomplete operator training; some operators do not recognize the impact of the solder alloy and are reluctant to switch off irons when not in use. Figure 1 shows erosion of the copper core due to lack of protective plating, which may have become damaged due to incorrect use of the iron tip.

If the base material of any soldering tip on irons or desolder stations is exposed to high temperatures and alloys prone to dissolution, this can still occur. If tips are being consumed faster than expected, examine the tip quality. Examine samples before and after use to ascertain the impact on soldering and wetting.

These are typical defects shown in the National Physical Laboratory’s interactive assembly and soldering defects database. The database (http://defectsdatabase.npl.co.uk), available to all this publication’s readers, allows engineers to search and view countless defects and solutions, or to submit defects online. To complement the defect of the month, NPL features the “Defect Video of the Month,” presented online by Bob Willis. This describes over 20 different failure modes, many with video examples of the defect occurring in real time.

Chris Hunt is with the National Physical Laboratory Industry and Innovation division (npl.co.uk); This email address is being protected from spambots. You need JavaScript enabled to view it.. His column appears monthly.