Ultrasonic Cleaning

Surface cleaning is freeing the surface from contaminants that are adhered chemically, physically, or mechanically to that surface. Contaminants are soils or impurities either generated during the forming process of new surfaces or deposited as foreign matter from surrounding environments. Smaller-sized particles are the most difficult to remove. Ultrasonic cleaning has been around for decades and is being used in applications ranging from microelectronics, hard-disk drives, medical devices, biomedical, automotive components, and optics to jewelry cleaning. Basically, ultrasonic energy is applied to a cleaning liquid or solution causing cavitation, which, in turn, scrubs the surface free from contaminants. However, there is a lot more involved beyond the basics of ultrasonic cleaning. Special attention must be given to a whole set of parameters in designing an effective cleaning process in order to achieve the high level of cleanliness, at the nano level, as demanded by continuous advancement in technology. This includes machine design and construction, sonic frequency, sonic power, proper and compatible cleaning chemistry, whether aqueous or solvent. Some other factors-such as parts handling, process parameters, packaging, and maintenance-are equally important and need to be included in the design of a cleaning process. © 2010 Elsevier Inc. All rights reserved.