Selective soldering nozzles: insights into wear mechanisms and future developments

Selective soldering utilises wettable metal nozzles for controlled application of solder to components. The wetting of solder to the nozzles is part of a complex mechanism that causes wear of the nozzle due to chemical interaction between the solder and the nozzle. This study explores the fundamental interactions between flowing solder and the nozzle.

Nozzles can last for hundreds of hours with the correct maintenance, however dewetting and eventual wear results in a loss of productivity and therefore revenue. Performance improvements to selective soldering nozzles allows for operation in more demanding process environments, producing higher quality and more reliable products, whilst also reducing process downtime and producing fewer defects. Thus far, limited work has been produced analyzing the efficacy of alternative alloys to improve the lifespan and wettability of selective solder nozzles.

A joint research project between industry and academia has been established to investigate the fundamental wear mechanisms of selective soldering nozzles and develop improved nozzles with increased wettability and lifetime. Alternative alloys are investigated for their operational viability.

Details of the methodologies employed will be given. Wear was quantified by proportional mass loss measured at regular time intervals throughout the nozzle’s operational life. Wettability was quantified by measurement of the contact angle with solder in an inert atmosphere to mimic in-situ conditions.

Insights into field performance of these new nozzles will be presented with reports from key testing partners.