TROUBLE SHOOTING OF ULTRASONIC CLEANING

Troubleshootingof ultrasonic cleaning process

Howto use ultrasonic cleaning machine correctly and efficiently, there are manyprofessional suggestions collected from KEEPLEADER’S training course, herein,hope this post can acknowledge more companies, who are using ultrasoniccleaning in their production process

01:In first shift working, our ultrasonic cleaning machine works not so expected,why is this so?

Ans:everyone clearly knows that ultrasonic cleaning must use aqueous media orchemical solution, this possibility of dissolved gases hided, in ultrasonicprocess, as high-frequency sound waves travel through aqueous media, areas ofcompression and rarefaction occur, during rarefaction, there is negativepressure, with enough loudness (sufficient amplitude), cavitation, voids ortear in the cleaning liquid occur, these are sometimes referred as cavitationor vacuum bubbles, when the bubbles collapse or implode during compression, theenergy (pressure and localized temperature) associated with this collapse isresponsible for the cleaning power of ultrasonic

 Inthe first shift cleaning, it is a near certainty that the aqueous mediacontains dissolved gases, this means that the ultrasonic bubbles formed duringrarefaction contain dissolved gases rather that a near-vacuum, the bubbles are“cushy”, so they do not collapse efficiency, turning on the ultrasonic for afew minutes prior to processing a product releases the dissolved gases, if theultrasonic machines have not been used for a whole, you should degas cleaningchemistries, or if fresh cleaning chemistry has been added, if in doubt, thendegas

02:We have a small unheated ultrasonic tank, as the day goes on, cleaningefficiency keeps getting better, is this all due to degassing?

Ans:Most of the improvement is probably due to temperature effects, in fact, as theday progresses, the ultrasonic transducers generate heat, causing thetemperature in the ultrasonic tank to increase, unless a temperature-controlledsystem is used, as the temperature increase, ultrasonic cleaning performancetents to improve, up to a point, the maximum performance temperature depends onthe cleaning chemistry, for water, the maximum temperature about 55 degree, asthe temperature increase, the viscosity of cleaning chemistry decreases, socavitation becomes increasing effect, in addition, as the temperatureincreases, cleaning effectiveness tents to increase, whether or not ultrasonicare used

03:Why does ultrasonic performance decline later in the day?

Ans:When the liquid reach its boiling point caused by heating and inherentultrasonic produced, for reason related to the degassing issue, the highertemperature, the higher the vapor pressure of the liquid, so the cavitationbubbles has more vapor, the bubbles become “cushy” and they do not implodeeffectively

04:The effectiveness of our ultrasonic cleaning line seems to vary throughout theday, why do we notice the worst problems when our throughout is highest?

Ans:The tank size usually design its average cleaning volume, if the cleaningbasket is overloaded, the ultrasonic energy cannot reach any corner because ofultrasonic intensity is dampened during travelling ,

05:How to choose correct ultrasonic frequency?

Ans:For small components and precision parts, KEEPLEADER suggest 40khg or bigger,the higher frequency, the bubbles is smaller, which can have good penetratingperformance into tiny blind holds, recesses, cracks, and gentle ultrasonicrubbing force, can well protect the substrate of cleaning parts, but thesmaller bubbles cannot contain higher temperature and pressure, so, for bigsize parts or heavy grease, 28khz play a good cleaning role, up to one point,this depends on the your current and anticipated production line and processrequirements

06:Our parts have heavy grease, we toss parts into the ultrasonic tank, leave themthere for hours, How long do we need to clean them?

Ans:Ultrasonic cleaning time usually set in minutes, 3 to 5 minutes is normal, but,tank normally heated or chemical added to reduce the water surface tension andimprove the bubble forming, many factories also using spraying process to speedup the cleaning, anyhow, the cleaning time is not hours, if have somehow, thechemical added might not be optimal, you need to adjust the change it, orultrasonic transducer might be malfunctioning, the placement of the transduceror power density might be incorrect for the task at hand, the parts might notbe suspended properly, so that parts are shadowed

07:If plastic tank, basket or fixture is ok for ultrasonic cleaning system?

Usually,no plastic in ultrasonic cleaning should be better, as mentioned previous,ultrasonic contains pressure and hot energy in vacuum bubbles, which implodewhen touching the substrate of cleaning parts, plastic tank, basket or fixturecan soften and dampen the suction force, so, stainless steel, metal basket isrecommended, we notice that some companies toss their parts into the plastictank with ultrasonic vibrations in testing and erroneously concludes that theirtank is workable, so not that, KEEPLEADER also advise you to consider your meshsize, try to use big mesh size in solid stance

08:Can we use acetone in ultrasonic cleaning for small-scale?Inflammable solvent is strongly forbidden in ultrasonic cleaning,acetone is over its flash point at ambient temperature, ultrasonic is ignitionsource, most of ultrasonic cleaning machine is designed for organic,non-inflammable solvent cleaning

09:Conclusions

Efficientultrasonic cleaning depends on its cleaning quality and productivity, forordering, you need to evaluate what ultrasonic cleaning system can do, even themost important is what cannot do, take a step back, look at your whole cleaningline, where need to be improved and changed