January 30, 2018
Ultrasonic cleaning systems can remove a wide variety of contaminants from the surfaces of parts to be cleaned, but specific material types can be removed more quickly and completely with additional measures. Oil-based dirt, grease and organic compounds can take the form of hard deposits that are difficult for the cavitation bubbles of the ultrasonic system to attack. The cleaning action of the bubbles will eventually break up and remove such material, but the process is more time-consuming than for other types of dirt.
In such cases heating the ultrasonic cleaning solution helps speed up the cleaning process. The hot liquid softens the deposits and makes it easier for the ultrasonic cleaning action to take place. Often a mild detergent is added as well to dissolve some of the contaminants. Cleaning with a heated solution is an effective way of making the ultrasonic cleaning system perform efficiently and at full capacity.
How Heat Improves Performance
The performance of ultrasonic cleaning systems depends on correctly matching the system to the characteristics of the parts to be cleaned and the materials to be removed. Robust parts such as metal automotive components can often be cleaned in a plain water bath using the strong cleaning action of the lower frequencies of ultrasonic systems. More delicate parts such as semiconductor wafers need the softer cleaning action provided by higher frequencies. If the material to be removed from such fragile parts is extensive and hardened, additional measures improve ultrasonic cleaning performance.
Depending on the contaminants to be removed, mild detergents and heat can be applied. The detergent and heat combination can be tailored to the particular material and an appropriate selection can improve cleaning performance substantially. Typically, contaminants are made up of several components and the detergent increases the solubility of some of them while heat softens the material and increases the effectiveness of the detergent. For the delicate cleaning of higher frequencies, the bubbles are smaller and less energetic. This lower energy is often not enough to remove hard materials quickly, but once heat has softened the material and the detergent has dissolved some of the bonds keeping the dirt in place, the small bubbles can clean quickly and completely.
Heating the Ultrasonic Bath
Ultrasonic cleaning systems are made up of ultrasonic generators, transducers and tanks. The ultrasonic generators produce the ultrasonic electrical signal and are selected based on the frequency needed for the cleaning application. The transducers are mounted in the bath immersed in the cleaning solution and they have to be matched to work with the selected generator. Both can be designed for a single or a range of frequencies
For the tanks, the only requirement is that they have to be large enough to hold the parts to be cleaned. If the parts are to be held in a basket to keep them away from the bottom and sides of the tank and avoid damage from vibrations, the tank has to be big enough to accommodate the basket.
For cleaning applications requiring heat, both the transducers and the tank must be designed for a heated cleaning solution. While cleaning applications may require different temperatures for optimal cleaning, a typical temperature may be around 80 degrees centigrade (176 degrees Fahrenheit).
Kaijo’s ultrasonic cleaning systems can accommodate such heating requirements and the company can help customers select suitable equipment and systems from their complete line of ultrasonic products. The transducers and tanks are heat-resistant up to 100 degrees centigrade (212 degrees Fahrenheit) and Kaijo’s customer support team can help determine what combination of detergent and heating is ideal for specific customer’s cleaning applications.Read More
January 19, 2018
Conventional degreasing and other cleaning processes involving the use of pressure cleaning, solvent and abrasives are on their way out in many industries. The change has come about for a number of reasons. The movement of industry towards green processes is one reason — solvents are often toxic to the environment. New environmental regulations being put in place by various state and local governments make it very hard for industries to get around, as well.
Cost- and efficiency-related concerns, however, have been the primary reason for the move away from conventional cleaning techniques. The chemicals needed in these approaches can be expensive, and can require further expense in the protection of the workers who use them. Safe disposal of toxic residue and the requisite inspections can take considerable investment, as well.
Yet, effective cleaning is essential to a great many industrial processes. From the immaculate surfaces needed prior to the application of powder coating processes, to the cleaning of high-tech filters and bearings at NASA, and from the jewelry industry to the automotive industry, safe, cost-effective and superior cleaning technology is a great need.
In Search of a More Affordable, and Cost-effective Cleaning Approach
In many industries that require the cleaning of industrial parts or other articles of various sizes, ultrasonic cleaning systems have proven to be the method of choice for a number of important reasons.
The action of ultrasonic energy on certain surfaces is observed in a number of scenarios. Anyone who is familiar with boats, for instance, has usually seen some damage to propellers — ultrasonic energy generated in the churn of propellers can be uncontrolled in its power; it often excavates tiny pits in the metal. When this energy is applied in a well-controlled manner, however, it can be used as a powerful cleaning agent.
Ultrasonic energy works in a very simple way — when dense, elastic media such as water is subjected to high-frequency energy, it expands and contracts so rapidly as to cause millions of microscopic fractures or tears. The small bubbles that are created collapse quickly after they are formed, often with great force. When such vacuum bubbles collapse close to the surface of an object, the force can knock surface contaminants off. Ultrasonic cleaning systems successfully apply ultrasonic energy to perform a great deal of useful work.
How do Ultrasonic Cleaners achieve their Effect?
Ultrasonic cleaning units consist of a tank usually filled with water, coupled to a powerful ultrasonic transducer capable of generating high-energy ultrasonic frequencies between 20 to 200 kHz. When objects to be cleaned — anything from industrial parts to dental equipment and jewelry — are placed in the bath, the ultrasonic waves generated create millions of cavitation bubbles. Localized areas can experience pressures over 10,000 psi, and temperatures over 10,000°F; dirt is effectively knocked off. Since these pressures and temperatures are created over microscopic areas, however, there is never any harm done to the work to be cleaned.
How are Ultrasonic Cleaners Superior to Conventional Cleaning Solutions?
Every nook is reached: With conventional cleaning — the pressure sprayers, solvents and abrasives — the cleaning action can often only reach areas clearly exposed. Ultrasonic energy, however, is able to get to hidden, unexposed areas.
The cleaning tends to be thorough: With cavitation bubbles forming and imploding in their millions, there is cleaning action in a way no water jet or abrasive can ever achieve. Even more importantly, the cleaning is achieved with little surface damage done, something that can be very important in the high-tech industry, the jewelry industry, or even the automotive industry, where delicate engine seals and finishes may need attention.
Insoluble contaminants are cleaned: Solvents are able to clean soluble contaminants; many contaminants, however, are simply resistant to the effects of solvents. Ultrasonic energy simply displaces such contaminants without the need for abrasive action.
Ultrasonic cleaners Help the Bottom Line
With such powerful and safe cleaning ability, the toughest cleaning jobs are usually completed in under an hour, with little need for supervisory personnel, or the need for the toxic waste disposal. With practically no moving parts, these appliances tend to require minimal maintenance, as well.
Ultrasonic cleaning systems are not all made the same. Kaijo, an industry leader in ultrasonic cleaning, has been at the cutting edge of the technology for over 65 years, developing purpose-built ultrasonic cleaning solutions for every industrial application. With the latest in ultrasonic cleaning deployed in practically every industry around the world, Kaijo has more experience with this technology than nearly any other name in the business.Read More