Introduction to Ultrasonic Cleaning

Ultrasonic cleaning is based on the phenomenon known as cavitation. In an ultrasonic tank, cavities (or bubbles) are formed by piezoelectric transducers attached to the bottom or sides of a cleaning tank. The piezoelectric effect occurs in a certain group of solid crystalline materials, which have no center of symmetry. When these materials are mechanically stressed, they produce an electric charge, and when an electric field is applied across two poles, the dimensions change. By applying high frequency (20-200Khz) and high voltage, these elements expand and contract rapidly at a rate proportional to the frequency of the applied voltage. As a result of the contraction and expansion, the pressure inside the liquid changes from negative to positive with respect to atmospheric pressure. During the contraction, the pressure in the liquid is negative, allowing the cavities inside the liquid to grow in size. Subsequently, in the next phase of expansion, the pressure in the liquid becomes positive, which causes the cavities to explode internally. The creation and the implosion of cavities cause an intense scrubbing action upon a submerged object. The size of the bubbles is microscopic and can penetrate the smallest cracks and holes to loosen the contaminants and remove them. 

All ultrasonic cleaners have three main components:

1. Ultrasonic generator or power supply that converts electrical energy from the wall (115VAC/60Hz) to high voltage and high frequency, then applied to ultrasonic transducers. 2. Ultrasonic transducers convert high voltage and frequency to mechanical vibration.

3. A cleaning tank that receives the mechanical energy and causes the cleaning media pressure to rise above and below the atmospheric pressure, thereby causing the formation and collapse of bubbles in the liquid. This process produces an intense scrubbing action that removes sediments from the submerged parts. Ultrasonic cleaning equipment ranges from small bench-top units to larger capacity machines up to several thousand-gallon models. The smaller units are self-contained with a built-in power supply and the tank, heater, and controls within a single enclosure. The larger systems require the power supply to be a separate console, and the very large units may utilize immersible transducers, which could then be mounted on the bottom or the side of the cleaning tank. Effective application of the ultrasonic cleaning process requires a number of parameters, such as operating frequency, watts per gallon of liquid, transducer efficiency, cleaning tank design, and liquid temperature. SonicWise has the experience and knowledge to design and manufacture the most efficient, rugged, and cost-effective ultrasonic cleaners for each application.