How Do You Clean Electronic Parts In An Ultrasonic Cleaner?

When it comes to electronic parts cleaning, the first question to ask is if it’s safe to submerge your part in a liquid medium. Typically, this is a non-issue, as most electronic components can be ‘washed’ provided this is followed by the right drying techniques.

There are two main categories of electronic parts considered for cleaning in an ultrasonic cleaner. A built up assembly or printed circuit boards.

Removing flux from Printed Circuit Boards (PCBs) or removal of solder paste off misprinted PCBs can give even seasoned geeks sleepless nights. This is irrespective of the fact whether they are assembled or reworked PCBs. If the components happen to have tight clearances or tubular geometry it gets even trickier.

An ultrasonic cleaner can easily remove flux from PCBs whether they are through-hole or surface-mount components. It can also get rid of the stubborn remains left over from the use of lead free or low-residue fluxes. In fact, in the printed circuit board and electronics production process, ultrasonic cleaners now play a vital part in reducing production costs.

One of the most attractive features of ultrasonic cleaning is its ability to reach tight spaces and blind holes that are typically impossible to reach manually or even with precision cleaning tools. Add to this the low risk of surface abrasion and a production engineer’s day – as far as the cleaning protocol is concerned – is made!

During the research and development phase, the harmonic vibration emitted by ultrasonic cleaning was found to damage certain components in electronic assemblies. This can be traced back to the 1950's, when some early generation semiconductors were damaged as reported by the air force.

In turn, this set off a traditional fear about using ultrasonic cleaners to clean electronic parts. However, the technology has progressed in leaps and bounds since then. Today ultrasonic cleaners use frequency modulation popularly called the ‘sweep’ technique that effectively eliminates the problem of harmful harmonic vibrations caused by standing waves.

The ultrasound process generates sonic vibrations in the liquid cleaning medium. This is done in alternating waves of rarefaction and compression that creates millions of tiny bubbles (rarefaction) that implode (compression). The implosion releases a liquid stream of high energy as micro-localized points that dislodge the contaminant off the surface.

When cleaning electronic components and assemblies make sure that you use the ‘sweep’ mode in the ultrasonic cleaner. This will vary the frequency creating ‘out-of-phase’ ultrasonic waves, which in turn will prevent the build of damaging ultrasonic oscillations.

Ultrasonic cleaning is more effective than traditional spray cleaning. Moreover, it can even help to improve SIR test results and reduce rework. Added to this there is a definite improvement in the reliability and longevity of PCBs cleaned with an ultrasonic cleaner. When you invest in an ultrasonic cleaner for your production floor, it pays for itself in no time. The savings in improved SIR results, reduced rework, and reduced defect rates are a testament to that fact.

The Author

Anindita Biswas is a marketing professional with a streak of geek that just refuses to go away!  At Tovatech she indulges in her passion for high precision engineering and scientific equipment.