Ultrasonic FAQs Answered by SharperTek

yhst-42112424359421_2250_394470You have questions about Ultrasonic Cleaning, and SharperTek has answers….and Production Automation has SharperTek! You can shop for ShaperTek products by visiting Production Automation online.

We offer a wide range of tabletop cleaners as well as automated multi-tank systems for large parts or high volumes of product. SharperTek does a great job of answering and explaining Ultrasonics, but you can always contact PAC if you have more questions, we are always here to help!

  1. What is an ultrasonic cleaning system?
  2. How does ultrasonic cleaning work?
  3. Will ultrasonic cleaning damage my parts?
  4. What are the components for ultrasonic cavitation and cleaning?
  5. Is there an optimum ultrasonic cleaning frequency?
  6. Are there different types of ultrasonic cleaning solutions?
  7. Are there cleaning solutions I shouldn’t use in an ultrasonic cleaning system?
  8. How do I get the best results from an ultrasonic cleaner?
  9. How do I get the best results from an ultrasonic cleaner?
  10. What is de-gassing?
  11. How do you degas an ultrasonic cleaning system?
  12. When should ultrasonic cleaning solution be changed?
  13. How long should an ultrasonic cleaning cycle be?
  14. Should parts be rinsed after an ultrasonic cleaning process?
  15. Why does an ultrasonic cleaner have a separate heater?
  16. How can I test an ultrasonic cleaning system?

Q. What is an Ultrasonic Cleaning System?

A. An ultrasonic cleaning system is an ultrasonic cleaning tank, and ultrasonic cleaning solution, a 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-cavitation action. The ultrasonic cleaning solution and he de-cavitation process work to “scrub” the part clean of oil, dirt, debris, and oxidation.

Q. How Does Ultrasonic Cleaning Work?

A. 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 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 nook 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.

Q. Will Ultrasonic Cleaning Damage My Parts?

A. 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 a mirror-like finish can lose its brilliance if immersed in an ultrasonic tank. A special dispersion plate is necessary to keep that from happening.

Q. What Are the Components for Ultrasonic Cavitation and Cleaning?

A. 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 to work together creating an environment where dirt, grime, and oxidation melt away from a dirty surface.
When the three components, ultrasonic waves, heat, and an 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.

Q. Is There an Optimum Ultrasonic Cleaning Frequency?

A. Ultrasonic cleaning systems operate in three frequency ranges:

  1. 20 to 40 KHz
  2. 40 to 70 KHz
  3. 70 to 200 KHz

The 20 to 40 KHz cleaning frequency range provides relatively fast cleaning, and is suited for most industrial applications with large parts have little or no intricate detail. 20 to 40 KHz systems are good for heavy duty cleaning.
The 40 to 70 KHz cleaning frequency range is suited for installations where parts have intricate detail, small orifices, or long tubes that need cleaning. 40 KHz typically require more power than 20 KHz and are slower to clean, but offer a finer cleaning.
The 70 to 200 KHz cleaning frequency range is suited for speciality 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.

Q. Are There Different Types of Ultrasonic Cleaning Solutions?

A. SharperTek supplies three types of ultrasonic cleaning solutions:

  1. Mild alkaline
  2. Mild acid
  3. Solvent Replacement

Which ultrasonic cleaning solution and ultrasonic cleaning process required 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 the 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 ins 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.

Q. Are There Cleaning Solutions I Shouldn’t Use In an Ultrasonic Cleaning System?

A. 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 in the ultrasonic cleaning process.
Use only those ultrasonic cleaning solutions recommended by the manufacturer of the ultrasonic cleaning system.

Q. Is There a Size Requirement for Ultrasonic Cleaning Systems?

A. 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 27 KHz tank, there should be a nominal clearance of 1.5 inches on each side, and 2 inches of unobstructed ultrasonic cleaning solution between the the part and the bottom of the tank. These distances could be reduced by half when a 40 KHz 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.

Q. How Do I Get the Best Results From an Ultrasonic Cleaner?

A. 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:

  • Fresh ultrasonic cleaning solution is not required for each cleaning, however, obvious degradation of the agent in use hampers the cleaning process.
  • Keep the heat at an optimal level – read your chemicals’ instructions for proper operating temperatures. Too much heat degrades the cavitation process. Never boil the agent.
  • Clean for the correct amount of time.
  • Choose the correct ultrasonic cleaning solution for the type of cleaning desired.
  • Be sure your system is de-gassed after filling with fresh ultrasonic cleaning solution.

Q. What is De-Gassing?

A. De-gassing is the removal of 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.

Q. How Do You De-Gas an Ultrasonic Cleaning System?

A. 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 owners or set-up manual that came with the ultrasonic cleaning system.

Q. When Should Ultrasonic Cleaning Solutions Be Changed?

A. 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 fresh solution.

Q. How Long Should an Ultrasonic Cleaning Cycle Be?

 A. 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.

Q. Should Parts Be Rinsed After an Ultrasonic Cleaning Process?

A. Parts should be rinsed after using ultrasonic cleaning to remove chemical residue left behind from the ultrasonic cleaning solution.

Q. Why Does an Ultrasonic Cleaner Have a Separate Heater?

A. Ultrasonic cleaning systems typically have an external heater to keep the ultrasonic cleaning solution at the optimal temperature between cleanings. The process of cavitation provides the heat required for cleaning during the cleaning cycle.

Q. How Can I Test an Ultrasonic Cleaning System?

A. Most of the problems encountered with ultrasonic cleaning systems result from improper control of one or more of the cleaning variables. If you feel o have the correct cleaning heat, ultrasonic cleaning solution and operating frequency, yet you think the system is not cleaning as well as it could, there are a few tests you can perform: the foil test and the glass slide test.
Foil Test: Cut three pieces of aluminum foil about 4″ to 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 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. Watch the video below for an example of what type of results you should expect from performing the foil test:
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.
© SharperTek

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Mel Meadows

Mel Meadows

Mel Meadows is a product specialist with over 13 years of experience. She’s a central source of expertise for thousands of industrial and critical-class products featured on the Production Automation web store. By working directly with manufacturers, Mel deciphers technical documentation and outlines product use in real-world environments. View her profile to learn more about proper techniques, protocol, and product usage in both industrial and cleanroom facilities.

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