The Effects of Ultrasonic Cleaning on Device Degradation—An Update

The effects of ultrasonic agitation on electronic components during PCB cleaning has long been the subject of controversy. This paper summarises the results of a series of studies into these effects for a range of components using CFC, aqueous and semi‐aqueous cleaning media. The variations with exposure time and power density under various ultrasonic stress conditions (loose, mounted on PCBs, or on purpose‐built test boards) are discussed. The results are encouraging and suggest that there is a large margin of safety when employing currently accepted regimes of operation and good quality components. However, the strong dependence of the damage accumulation on power density emphasises the need to specify and tightly control the power density used.