An ultrasonic cleaning system is an ultrasonic cleaning tank, an ultrasonic cleaning solution, an heating element, immersion baskets and electronic controls. Together, the system creates ultrasonic waves that sonicate the ultrasonic cleaning solution. This sonication creates a high energy ultrasonic de-cavitation process in the solution, creating the ultrasonic cleaning action.
The actual cleaning process is carried out in the ultrasonic cleaning tank. A basket supporting the parts is lowered into the heated solution where it is exposed to the ultrasonic de-cavitation process. The immersed parts receive an ultrasonic cleaning bath through the power of the ultrasonic waves’ de-cavitating action. The ultrasonic cleaning solution and the de-cavitation process work to “scrub” the part clean of oil, dirt, debris and oxidation.Go To Top
Dirty items come clean in ultrasonic cleaning systems when millions of superheated bubbles scrub grime and oxidation away with stunning results. How? Through the process of de-cavitation.
Ultrasonic cleaning systems send high frequency sound waves ripping through an ultrasonic cleaning solution leaving superheated bubbles in the waves’ wake. When these bubbles, called cavitatons, collapse, called decavitation, the heat and energy of their implosions work with the specially formulated ultrasonic cleaning solution to remove dirt, oils, residue and oxidation from the surface of the contaminated item.
Imagine the ability to get into the tiniest of nooks and crannies where dirt and grime hide, and then imagine scrubbing that surface ultra clean. With conventional cleaning – brushes, rags and elbow grease – this task seems impossible. But the cavitating cleaning action of an ultrasonic cleaning system does just that – It goes where brush bristles can’t.Go To Top
Generally, ultrasonic cleaning is safe for all materials; however, prolonged exposure to ultrasonic cleaning chemicals and detergents may interact adversely with the surface of certain metals. For more information regarding the specific cautions of using particular ultrasonic cleaning solutions, and general instructions for safe use of an ultrasonic cleaning system, consult the manufacturer of the product. Aluminum with mirror like finish can lose its brilliance if immersed in an ultrasonic tank. A special dispersion plate is necessary to keep that from happening.
Ultrasonic waves, heat and an ultrasonic cleaning solution are the three components at the heart of an ultrasonic cleaning system. Ultrasonic waves sonically cavitate and heat the ultrasonic cleaning solution, causing these three components work together creating an environment where dirt, grime and oxidation melt away from a dirty surface.
When the three components, ultrasonic waves, heat and ultrasonic cleaning solutions come together, ultrasonic cleaning produces jaw-dropping results. Ultrasonic cleaning is simply a superior form of cleaning that replaces hours of intensive labor and inferior cleaning results, and removes the need for flammable solvents.Go To Top
Ultrasonic cleaning systems operate in three frequency ranges: 20 to 40 Khz, 40 to 70 Khz, and 70 to 200 Khz. The system frequency to use depends on the type of cleaning required.
The 20 to 40 Khz cleaning frequency range provides relatively fast cleaning, and is suited for most industrial applications with large parts having little or no intricate detail. 20 to 40 Khz systems are good for heavy duty cleaning.
The 40 cleaning frequency range is suited for installations where parts have intricate detail, small orifices, or long tubes that need cleaning. 40Khz systems typically require more power than 20Khz systems and are slower to clean, but offer finer cleaning.
The 70 to 200 Khz cleaning frequency range is suited for specialty operations such as the fine, gentle cleaning of optics, semiconductor wafers and hard-disk-drive components.
The higher the frequency, the gentler the cleaning, while lower frequencies are designed to “scrub” heavily soiled surfaces.Go To Top
SharperTek supplies three types of ultrasonic cleaning solutions: mild alkaline, mild acid and solvent replacement. Which ultrasonic cleaning solution an ultrasonic cleaning process requires depends on what type of grime or deposit is being removed.
A mild alkaline ultrasonic cleaning solution is suited for the cleaning of oily parts. This agent works by breaking down the ionic bond that has formed between an oil and a metal. As the part is cleaned, the oil is dissolved and is dispersed into the liquid.
A mild acid ultrasonic cleaning solution is suited for removing rust and oxidation. An oxide remover, the mild acid solution is suited for applications where oxidation has coated the surface of the part.
A solvent replacement ultrasonic cleaning solution, or “shellac-buster”, removes rust, oxidation, carbons and oils. Shellac-busters are suitable for applications where a solvent like kerosene may have once been used. Solvent replacement agents are faster working than alkaline agents, and they perform in a similar fashion by breaking down ionic bonds and removing oxidation and are non-hazardous.Go To Top
You should never use flammable liquids in an ultrasonic cleaning system. Because of the heat generated by the cavitation process, dangerous conditions will occur if flammable liquids are used for ultrasonic cleaning.
Use only those ultrasonic cleaning solutions recommended by the manufacturer of the ultrasonic cleaning system.Go To Top
Ultrasonic cleaning systems are sized based on the size of the parts being cleaned. The part size determines the size of the immersion tank. The rule of thumb is to allow the tank to be one third larger than the largest part to be cleaned.
When a part is immersed in a 27KHz tank, there should be a nominal clearance of 1.5 inches on each side, and there should be 2 inches of un-obscured ultrasonic cleaning solution between the part and the bottom of the tank. These distances could be reduced by half when a 40KHz tank is being used.
A part being cleaned should never touch the bottom of the tank. This is equivalent to placing your finger directly on the speaker of your sound system. Damage may occur.Go To Top
Managing the type of ultrasonic cleaning solution used, length of cleaning cycle, correct size tank, correct operating frequency and choosing the best temperature for operation are all factors in getting the best results from an ultrasonic cleaner. To keep an ultrasonic cleaning system operating at optimal performance, keep the following in mind:
De-gassing is the removal of dissolved oxygen trapped in a liquid. In ultrasonic cleaning systems, trapped, dissolved oxygen in the ultrasonic cleaning solution will hinder the ability of the system to clean. This dissolved oxygen must be removed from the system by de-gassing.Go To Top
You de-gas an ultrasonic cleaning system by sonicating the ultrasonic cleaning solution. This is done by simply running the system with the tank filled to the proper level with ultrasonic cleaning solution, but unloaded of dirty parts. Run the system for the time period stated in the owner or set-up manual that came with the ultrasonic cleaning system.Go To Top
It is not necessary to change the ultrasonic cleaning solution for each cleaning cycle. However if there is a noticeable decrease in the effectiveness of the cleaning cycle, or if there is noticeable dirt or debris in the fluid it may be time to replenish the tank with a fresh solution.Go To Top
There is no set amount of time or “typical” cleaning cycle. How soiled the part is, the temperature of the tank, how clean the part is to be, and the condition of the ultrasonic cleaning solution all contribute to the length of the cleaning cycle.
An experienced operator may be able to approximate the time required to clean an object, ultimately however, an inspection is required to determine if the desired state of clean has been obtained.Go To Top
Parts should be rinsed after ultrasonic cleaning to remove chemical residue from the ultrasonic cleaning solution.Go To Top
Ultrasonic cleaning systems typically have an external heater to keep the ultrasonic cleaning solution at the optimal cleaning temperature between cleanings. The process of cavitation provides the heat required for cleaning during the cleaning cycle.Go To Top
Most of the problems encountered with ultrasonic cleaning systems result from improper control of one or more of the cleaning variables. If you feel you have the correct cleaning heat, ultrasonic cleaning solution and operating frequency, yet think the system is not cleaning as well as it could, there are a few test you can perform: The foil test and the glass slide test.
Foil test: Cut three pieces of aluminum foil to about 4” by 8”. Fold each of the foils over a rod such as a coat hanger and suspend the foil pieces in the tank, with one piece in the center of the tank, and each of the other two at opposite ends of the tank. Be sure the tank is filled to the correct level. Turn on the ultrasonic cleaning system. In ten minutes each piece of foil should be pitted, wrinkled and degraded to the same degree.
Glass slide test: Wet a frosted piece of glass with tap water, and draw an “X” on the frosted side of the glass, corner to corner with a number two pencil. Make sure the tank is filled to the correct level with fresh ultrasonic cleaning solution. Immerse the glass into the tank and activate the system. The “X” should begin to be removed immediately, and should be gone completely from the glass within 10 seconds.Go To Top