Ultrasonic Systems for Precise Cleaning Applications
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Kaijo Shibuya America Inc. Exhibiting at SEMICON West 2017

June 21, 2017

Kaijo Shibuya America Inc. will be exhibiting at SEMICON West 2017, at Booth 5518 North Hall, from July 11-13 at the Moscone Center in San Francisco. Come by our booth to talk with us and learn how our new Phenix Hyper wave can enhance the uniformity of your ultrasonic cleaning process. Kaijo is an industry leader in megasonic and ultrasonic cleaning technology and offers a wide selection of state-of-the-art products and innovations not found with other ultrasonic cleaning manufacturers. (more…)

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Ultrasonic Cleaning 101: What Are Ultrasonic Waves and How Do They Clean?

June 19, 2017

Ultrasonic cleaning systems use ultrasonic waves to clean parts, tools and equipment quickly and effectively. A typical system is made up of an ultrasonic generator, a transducer and a cleaning tank. The generator produces an electrical signal at the required ultrasonic frequency. Ultrasonic frequencies used range from about 26 kHz to 200 kHz, and a generator may be designed for a single frequency or a frequency range.

The transducers convert the electric signal to physical vibrations that can create ultrasonic waves in a liquid. The transducer is submerged in the cleaning solution and includes a heavy metal plate. When the transducer receives the electric signal from the generator, the metal plate vibrates at the ultrasonic frequency and fills the liquid in the cleaning tank with ultrasonic waves.

The cleaning tank holds the parts to be cleaned, the cleaning solution and the transducer. It may include a basket to keep the parts from touching the tank walls and bottom, and it may include a heater to warm the liquid. High performance industrial ultrasonic cleaners work with plain cold water but adding a mild detergent and heating the solution can improve cleaning performance for some contaminants.

How Ultrasonic Waves Clean

The ultrasonic waves in the cleaning liquid remove contaminants and dirt from the surfaces of the parts to be cleaned through the action of cavitation bubbles. Just like waves on the surface of a body of water, ultrasonic sound waves have peaks and troughs. When the sound waves travel within a cleaning solution, the peaks and troughs become areas of high and low pressure.

In the low-pressure areas, cavitation bubbles form and the bubbles collapse under high pressure. As an ultrasonic sound wave trough passes the surface of a part to be cleaned, the cavitation bubbles form along the surface. When the high-pressure peak of an ultrasonic wave passes by, the bubbles collapse and release energy which produce a scrubbing action on the surface. This process repeats at the frequency of the ultrasonic wave. As a result, millions of microscopic bubbles form and collapse many thousands of times per second delivering intensive cleaning action by loosening dirt and contaminants and scrubbing the surfaces to be cleaned.

How System Frequency Affects Cleaning Performance

While all industrial ultrasonic cleaners operate the same way, the operating frequency influences what kinds of parts can be cleaned most effectively. In general, low frequencies can better deal with heavy dirt and contamination on hard surfaces while higher frequencies are used for delicate cleaning applications.

The sound wave pressure peaks of low frequencies such as 26 kHz to 38 kHz are relatively far apart, leaving more time for the cavitation bubbles to grow. The comparatively large bubbles give off a lot of energy when they collapse, and the resulting cleaning action is especially intense. Frequencies such as 100 kHz or higher leave less time for the bubbles to grow and the smaller bubbles give off less energy when they collapse. The cleaning action at the higher frequencies is gentler, becoming less aggressive as the frequency rises.

The low frequencies are suitable for items such as metal tools, glass or hard disk drive components. High frequencies are used for more fragile items such as delicate machined parts, semiconductor components or solar cells. Choosing the correct frequency and other ultrasonic system features is critical for optimal cleaning performance.

How Kaijo can Help You Choose the Right System

Global ultrasonic cleaning system manufacturer Kaijo offers a wide range of standard and turnkey solutions and can customize systems to match special cleaning needs. The company has the expertise to evaluate cleaning applications and suggest the ideal system to match specific requirements. Kaijo’s ultrasonic cleaners can clean quickly and completely to help increase manufacturing productivity, reduce the use of harsh cleaning chemicals and improve output quality with better cleaning performance.

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Why You Need an Ultrasonic Cleaning System for 3D Printed Parts

May 30, 2017

Advances in 3D printing have made this new technology widely accessible with broad manufacturing capabilities. The 3D printers work by depositing tiny drops of material in thin layers according to a digital design. The material of the 3D part is usually a type of resin or plastic that is in liquid or paste form when it is deposited and then hardens into a solid. The printers make it possible to create items with complex shapes as prototypes or samples and they can be used to make test pieces before starting production.

Complex items may require several types of material and there may be overhangs, gaps or complicated structures. The 3D printer makes sure that overhangs and structures don’t collapse by depositing supporting material underneath. Some parts of the item may have to slide or rotate over, around or through other parts. For such parts, the printer deposits thin layers of separating material to make sure the sliding or rotating parts don’t stick together. When the item is finished, it may have several areas where such supporting or separating material is present. Before the 3D printed item can be used, the extra material must be removed.

Ultrasonic Cleaning Systems Can Clean 3D Printed Parts

Removing extra supporting and separating material from a 3D printed part quickly and effectively can be difficult. The layers to be removed are often thin and not easily accessible. Scrubbing or mechanical removal is time-consuming and can leave an unwanted residue. Using a specially formulated solvent to dissolve the material can require lengthy soaking times and result in incomplete removal. An ultrasonic cleaner is often an excellent solution for the cleaning of these parts and the removal of the unwanted material. Ultrasonic cleaners clean quickly and clean thoroughly, even around complex shapes and in hard-to-reach places.

An ultrasonic cleaning system works by using ultrasonic waves to generate cavitation bubbles in a cleaning liquid. The bubbles form and collapse in time with the frequency of the sound waves. This bubble action results in an intense scrubbing effect wherever the cleaning liquid touches the surface of the 3D printed item. If the cleaning liquid contains a solvent for the unwanted material or if the material is soft compared to the rest of the item, only the unwanted material will be removed.

Kaijo Ultrasonic Cleaners for Optimum Results

Kaijo’s ultrasonic cleaning systems can clean 3D printed parts and remove unwanted filler material quickly and effectively. The Phenix III turnkey system is ready to clean with a minimum of installation and set up work and is sized to handle most typical 3D printed items. The system operates at 26 kHz or 38 kHz and delivers 600 W or 1200 W of cleaning power.

For bigger 3D printed items, Kaijo ultrasonic generators, transducers and tanks can be used to set up special solutions aimed at a customer’s specific cleaning needs. The components can operate with the solvents needed for 3D printed parts cleaning and the transducers mounted in the tanks are rated for up to 100 degrees centigrade. When a customer has existing cleaning tanks to be re-used, Kaijo can help design custom configurations with multiple transducers to deliver excellent cleaning action in large tanks. Kaijo’s extensive experience with ultrasonic cleaning systems helps customers get the 3D cleaning performance they need. If you want a quote or free consultation on which ultrasonic cleaning systems should be used for your application call Kaijo or email info@kaijo-shibuya.com.

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How Ultrasonic Cleaners Utilize Cavitation

May 17, 2017

Ultrasonic cleaning systems use cavitation in cleaning liquids to remove contaminants and surface dirt from a wide variety of parts that need cleaning. Cavitation bubbles are created by the action of sound waves in a cleaning solution. As the ultrasonic sound waves travel through the liquid, bubbles appear in the low-pressure troughs of the waves and collapse in the high-pressure peaks. The creation and collapse of the bubbles results in a powerful scrubbing action that operates throughout the liquid.

Manufacturing plants that have equipment cleaning needs can benefit from the fast, thorough cleaning provided by industrial ultrasonic cleaners. Parts such as nozzles, containers, valves and tools can often be cleaned completely in as little as ten minutes.  Manufacturers of parts or finished products can use ultrasonic cleaners to remove process material before shipping or clean products such as medical devices, solar cells, jewelry and ceramics. Ultrasonic cleaners work quickly and effectively without harsh chemicals.

How to Get the Cleaning Action You Need

The action of the cavitation bubbles can be adjusted by varying the ultrasonic frequency and the cleaning power. At low frequencies such as 26 kHz to 38 kHz, the ultrasonic wave peaks and troughs are comparatively far apart, resulting in larger bubbles. When large bubbles are created and collapsed, the scrubbing action is comparatively intense. Such low frequencies can clean rugged parts with stubborn dirt rapidly but they are not suitable for more delicate parts or parts with soft surfaces where the large bubbles may cause pitting or other damage.

Intermediate frequencies such as 78 kHz to 160 kHz result in smaller bubbles and less aggressive cleaning. Systems operating at these intermediate frequencies can clean fragile machined parts and soft materials. Even higher frequencies such as 1 MHz and above deliver very gentle cleaning action and are suitable for cleaning delicate semiconductor devices and microscopic structures. Customers can select either a single-frequency cleaner suitable for a clearly defined cleaning task or cleaning systems that can operate at several frequencies to deliver the level of cleaning action required for different cleaning applications.

Depending on the size of the parts to be cleaned, the power of the ultrasonic cleaning system must be high enough to generate bubbles throughout the cleaning tank. A single ultrasonic transducer array can deliver power of up to 1200 W and clean parts up to about 500 mm (20 inches) long. For larger parts needing bigger tanks, several ultrasonic transducers can be mounted along the bottom or on the sides. A custom design for such applications can use existing or new tanks to match customer needs.

Benefits of Kaijo’s Ultrasonic Cleaning Systems

Kaijo offers a complete line of industrial ultrasonic cleaners. Turn-key systems such as the Phenix III include an ultrasonic generator and a tank with the transducers already mounted. These systems are ready to start cleaning with a minimum of installation and setting up.

Alternatively customers can opt to buy ultrasonic generators such as the Quava or Phenix Series and buy transducers and tanks separately. These are excellent options for applications where existing cleaning tanks are to be re-used and Kaijo can help with such customizations.

Benefits of using these systems for industrial cleaning applications include the following:

  • Quick and complete cleaning of all types of parts to remove a variety of contaminants
  • Effective cleaning of complex shapes and parts with holes and crevices
  • Cleaning without harsh chemicals or mechanical scrubbing
  • The safe, efficient cleaning process results in improved facility performance and better quality output

Kaijo can advise customers on how to best satisfy their cleaning requirements and help them select the system they need. The company’s experience and expertise help ensure that the ultrasonic cleaners meet and exceed expectations. If you would like a quote or free consultation on how industrial ultrasonic cleaners can be used for your cleaning application call Kaijo or email info@kaijo-shibuya.com.

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Ultrasonic Cleaners for Pharmaceutical Equipment

April 28, 2017

Pharmaceutics manufacturers have challenging cleaning requirements when equipment such as pill punches and filling machine valves are used with different materials or when they become contaminated with mold or bacteria. Traditional cleaning methods with toxic chemicals bring their own contamination issues, and cleaning by shaking and agitation may not penetrate into inaccessible spaces or hard-to-reach crevices. Industrial ultrasonic cleaners offer an environmentally friendly cleaning solution that removes contaminants thoroughly and quickly at a low operational cost.

Issues With Traditional Cleaning

Exposed pharmaceutical parts such as pill punch dies or containers are usually cleaned with small bristle or wire brushes and solvents. While such cleaning can be effective, it is labor-intensive and slow. When the shapes to be cleaned are more complex and include internal surfaces, such cleaning is often not complete.

For cleaning inaccessible internal surfaces such as the inside of valves or nozzles, strong chemicals acting together with agitation or shaking as well as high impact spray cleaning may be used. The use of these aggressive cleaners required to sterilize the equipment often means technicians have to wear extensive protective gear and even then contaminants may remain in small crevices.

The main issues with this type of traditional cleaning are that it is time-consuming, potentially hazardous, expensive and not completely effective. As a result, costs are high and product quality can suffer. Ultrasonic cleaning can address both these issues.

How Ultrasonic Cleaning Works

Pharmaceutical devices and parts to be cleaned have to be detached and placed in the ultrasonic bath. Pill dies, valves, nozzles and hoses are placed in a stainless steel basket and immersed in a tank containing a water-based solution of a mild detergent. When the ultrasonic cleaning system is switched on, there can be a buzzing depending on the frequency used and a slight agitation of the tank liquid can often be observed.

In the liquid bath, the ultrasonic transducer is converting an electrical signal of perhaps 40 kHz into ultrasonic waves that travel through the liquid. Higher frequencies are used for delicate components while lower frequencies, down to about 20 kHz, are used for the powerful cleaning of rugged parts.

As the sound waves travel through the liquid, they produce microscopic cavitation bubbles whose formation and collapse produce the cleaning action. The bubbles loosen any material, down to the original machined or manufactured surface. The loose material floats away and is filtered out.

The sound waves travel through the parts and create bubbles wherever there is liquid. As a result, even threads, cracks and crevices and internal surfaces are cleaned thoroughly via the bubble action. Depending on the frequency and the power of the ultrasonic system, cleaning can take as little time as ten minutes and for even for challenging applications, the ultrasonic cleaning method works more quickly than traditional cleaning.

Kaijo Industrial Ultrasonic Cleaners

Industrial ultrasonic cleaners from Kaijo can clean pharmaceutical equipment quickly and completely with a low total cost of ownership. Managers and decision makers at pharmaceutical manufacturing facilities can choose turnkey solutions such as the Phenix III system or individual components such as the Quava ultrasonic generator, ultrasonic transducers and cleaning solution tanks.

Buying ultrasonic generators and transducers separately is especially useful when customers want to use existing cleaning tanks in the manufacturing facility. Immersible or bolt-on transducers can be placed in the tanks or bolted on to the sides or bottom. Large tanks can have multiple transducers installed and Kaijo can help configure the appropriate generator and transducer installation.

Whether customers can satisfy their requirements with standard equipment or whether they have custom applications, Kaijo can supply an ultrasonic cleaning solution. The company has over 65 years experience in the field of ultrasonics and supplies pharmaceutical companies with cost effective ultrasonic cleaners to address their specific requirements.

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Using Ultrasonic Cleaners to Clean Carburetors and Engine Parts of Motorcycles and Autos

April 21, 2017

The carburetors and other related engine parts on older or vintage motorcycles and autos are mostly mechanical devices designed to achieve precise fuel-air mixtures for their internal combustion engines. They are built of valves, chambers, floats, jets and other intricately designed components placed together in fine balance.

When a carburetor and other engine parts become greasy and coated with soot from extended use, it can result in difficult starts, poor power delivery and fuel inefficiency, soot-filled exhaust, timing sneezes and overheating. Visible fuel leaks from the carburetor are not uncommon, either. Cleaning carburetors and other engine parts requires the ability to thoroughly clean all surfaces of the component. This can be a tough challenging endeavor.

The conventional way to clean carburetors is to painstakingly disassemble the component to separate every intricate part, and to manually scrub every nook with powerful, hazardous chemicals. The entire process can be very time-consuming. Not only is it very hard taking these intricate components apart, it can be challenging putting them back together, as well. This is where the use of ultrasonic cleaning technology enters the picture.

What is ultrasonic cleaning?

Ultrasonic cleaning technology was first developed by RCA way back in the 30s. In 1957, Kaijo Corporation developed their first ultrasonic cleaner that was the beginning of their product line of industrial ultrasonic cleaners. The use of the Ultrasonics has continually evolved over the years. Many advances in the past decade alone have made the technology particularly accessible and affordable to businesses that would have previously deemed it out of reach.

Ultrasonic cleaning is a powerful, but gentle cleaning method that makes practical use of a natural phenomenon called cavitation. The term refers to the behavior of bubbles in liquid, when they are subjected to intense levels of pressure variation.

When rapid changes of pressure pass through a liquid, the condition creates tiny bubbles that periodically implode to intense shockwaves. The forces generated by such implosions can be great enough to dislodge grease, rust or other stubborn deposits.

While the cavitation phenomenon is one that designers strive to prevent in certain applications such as marine propeller design, it is a useful one when correctly applied to various industrial processes that involve tough cleaning applications.

How does ultrasonic cleaning technology help clean motorcycle and auto carburetors?

Motorcycle and auto carburetors use complex, intricate constructions, and cleaning layers of heavy, burned-on grease can present a challenge to mechanics. It requires the use of ultrasonic cleaning technology to address the cleaning action needed.

Industrial ultrasonic cleaners come with a cleaning tank or bath that includes either a built-in or removable ultrasonic cleaning transducer. The cleaning tank is filled with ordinary water or a mild cleaning solvent, and the carburetor and other engine parts to be cleaned are placed in the tank. The unit generates sound waves of ultrahigh-frequency to rapidly cycle pressure waves in the tank which create a powerful cavitation effect. Millions of tiny, microscopic bubbles form over the surface of the carburetor and other parts implode with strong force, each implosion generating enough power to dislodge the grease, rust or baked-on dirt on the surface.

Since the liquid of the tank and the sound waves passing through it reach every crevice on the surface of and inside the carburetor, there is no area left untouched. In no more than a few minutes, the carburetor and other engine parts emerge clean, completely stripped of grease, rust and other contaminants that were on the surface.

No part is too complex for ultrasonic cleaning. The process can save hours upon hours of human labor.

The benefits of Industrial ultrasonic cleaners

One might imagine that forces of cavitation strong enough to eat grease and rust away would be powerful enough to cause damage to metal, as well. While such an effect is technically possible, it is prevented in practice, by using the right ultrasonic equipment to apply the appropriate frequency and power for the specific cleaning application needed.

Megasonic (frequencies of 200kHz-1.2 MHz) and Ultrasonic (frequencies of 20khz-200kHz) cleaning is one of the most advanced cleaning approaches in existence; such technology is used to clean everything from semiconductor wafers to computer parts, to large rugged industrial parts safely and effectively.

Kaijo’s Industrial ultrasonic cleaners can be used to address a wide variety of motorcycle and automotive cleaning applications. The environmental and monetary benefits of ultrasonic cleaners are also quite significant. The method requires no use of harsh chemicals or solvents, and is therefore healthy both for the environment and for workers. Contact Kaijo for a free consultation or quote on using the right ultrasonic cleaning equipment for your cleaning application.

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Using Ultrasonic Cleaning Systems to Safely and Effectively Clean Circuit Boards

March 28, 2017

Ultrasonic cleaning systems work by utilizing a transducer plate in contact with a cleaning solution to produce cavitation bubbles that scrub the materials to be cleaned. Such systems can remove contaminants from a variety of surfaces and they work more rapidly than conventional cleaning systems. Ultrasonic cleaners are ideally suited for the cleaning of circuit boards safely and effectively because they don’t need dangerous chemicals and they clean completely. Kaijo offers a range of ultrasonic cleaning systems and can help select the system that best matches particular circuit board cleaning needs. For special circuit board cleaning applications, the company can customize systems to meet specific requirements.

Advantages of Ultrasonic Cleaners

By relying on cavitation bubbles for cleaning action, ultrasonic cleaning systems have a number of advantages over traditional cleaning methods. These include the following:

  • Cleaning is rapid and complete down to the original surface
  • Because bubbles form wherever there is cleaning solution, the systems can clean complex geometries, through holes and into crevices
  • Cleaning intensity can be varied by adjusting the ultrasonic frequency
  • The cleaning solution is water-based without strong chemicals

A correctly designed ultrasonic cleaning installation can clean circuit boards without the problems often faced with spray washing or mechanical scrubbing. When electronic circuits components have surfaces that are inaccessible via traditional methods, ultrasonic cleaning may be the only solution.

Benefits of Ultrasonic Cleaning Systems

The advantages of using ultrasonic cleaners result in a number of specific benefits. When harsh chemicals are no longer used for cleaning, printed circuit board manufacturers can save the cost of chemicals. Costs associated with chemical handling and disposal are also reduced and cleaning process safety is increased since ultrasonic cleaning uses only mild detergents in an aqueous solution.

The rapid and complete cleaning action of ultrasonic cleaners can increase productivity and improve output quality. When flux and solder paste are removed quickly, circuit boards are ready for additional production steps and facility throughput can increase. The complete removal of contaminants, even from hard-to-access places on the circuit boards, can reduce failure rates caused by incomplete cleaning and result in higher quality output.

The ability to adjust cleaning intensity means that ultrasonic cleaners can be used for rough cleaning of heavy contaminants as well as for removal of less severe contamination from easily-damaged components. The cleaning intensity depends on the system frequency, low frequencies generating comparatively large bubbles with intense cleaning action while the smaller bubbles of higher frequencies clean more gently. This flexibility lets circuit board manufacturers use ultrasonic cleaning systems for many different cleaning applications.

Kaijo’s Ultrasonic Cleaning Systems

When considering the purchase of an ultrasonic cleaning system, the operating frequencies and the system’s physical configuration are critical for obtaining the best cleaning performance possible. In addition to selecting the appropriate frequencies, adequate system power is important for effective cleaning.

Systems can be turnkey or customers can select individual components. Turnkey systems are the easiest to install, but if circuit boards are to be cleaned in existing tanks, separate ultrasonic generators and immersible transducers may be appropriate. Clearly defined cleaning tasks can be carried out with a system limited to one or two frequencies while a flexible cleaning process might require a system that can operate at many frequencies.

Kaijo can evaluate a circuit board cleaning process and establish possible ultrasonic cleaning system configurations and their characteristics. The company offers a complete line of systems and individual components and can put together packages that satisfy the requirements of any ultrasonic cleaning application. Once the requirements are clear, Kaijo can provide turnkey systems such as the Phenix III, components such as ultrasonic generators and transducers, or put together a custom installation to meet the needs of special cleaning processes.

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Selecting Ultrasonic Transducers for Industrial Cleaning Applications

March 15, 2017

Ultrasonic cleaning systems consist of an ultrasonic generator, a transducer and a cleaning tank. The generator produces the electric signal at the selected frequency while the ultrasonic cleaning transducer changes the signal into compression waves in the cleaning solution. The cavitation bubbles that are responsible for the cleaning action of the system appear in the troughs of these compression waves.

The transducer produces compression waves through the action of piezoelectric material that expands and contracts when subjected to the electric signal. The transducer uses the electric signal from the ultrasonic generator to change the height of its piezoelectric material in tune with the signal. That way it can generate compression waves when its metal surface, tightly bonded to the piezoelectric material, vibrates at the selected frequency.

Ultrasonic cleaners can help improve productivity in industrial manufacturing plants that require cleaning of parts, components and tools. Mounting ultrasonic transducers on cleaning tanks can result in faster and more complete cleaning and a reduction in the use of harsh chemicals. Cleaning systems using these transducers can clean machined parts, tools, wires, lenses, glass and ceramics without damaging them and the systems can clean complex geometries, holes and crevices where traditional cleaning methods fail.

Physical Characteristics of Ultrasonic Cleaning Transducers

Ultrasonic transducers arrays must be able to withstand severe vibrations, immersion in cleaning solutions and high temperatures. Their construction must be heavy and rugged enough to be able to generate powerful compression waves and their surfaces must be designed to resist pitting due to the action of cavitation bubbles.

Kaijo transducer elements are hermetically sealed in a 316L polished stainless steel housing. They are designed to withstand immersion in cleaning solutions up to 100 degrees Centigrade and their piezoelectric characteristics will not degrade over time. The heavy duty enclosure and internal arrangement withstand the intense vibrations at high power and low ultrasonic frequencies and their surfaces can withstand cavitation.

Kaijo transducers are available in bolt-on, immersible or mounted versions. The immersible transducer is an independent unit connected to an ultrasonic generator via a cable. It can be placed in any tank and can be moved at any time. The immersible transducer is ideal for applications where there are a number of existing tanks and flexibility with different cleaning tasks is required.

Mounted transducers are integrated into tanks and are usually purchased with the tank for clearly defined cleaning applications. Bolt-on transducers are similar to mounted units but can be bolted onto the bottom or sides of tanks in single or multiple-unit configurations.

Electrical Characteristics

Key process parameters for ultrasonic cleaning systems are frequency, power and transducer characteristics. The ultrasonic frequency determines the size of the cavitation bubbles and the intensity of the cleaning action. Low frequencies generate comparatively large bubbles for robust cleaning while high frequencies produce smaller bubbles with a gentle cleaning action. The transducers have to be able to operate at the frequency selected for the system.

The system power, in watts, determines total cleaning power. Large tanks need more power and may require several transducers for optimum cleaning. Kaijo can help customers determine which frequencies are appropriate for their cleaning application and how much power they will need.

Kaijo ultrasonic sets are available for a complete range of frequencies from 26 kHz to 2MHz and with variable power output maximums of 600W or 1200W. In addition to offering ultrasonic systems and ultrasonic cleaning transducers as standard products, Kaijo has the experience and in house expertise to evaluate customer needs and propose custom solutions.

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How a Megasonic Cleaning System Removes Submicron Particles from Delicate Components

February 27, 2017

Megasonic cleaning systems use high frequency generators and transducers operating in the MHz range to clean delicate parts such as silicon wafers, and related microelectronic devices. Semiconductor manufacturing processes rely on repeated cleaning operations, and megasonic systems clean more rapidly and more completely than other cleaning methods in many applications. Megasonic cleaning systems are especially effective in the removal of submicron particles during the manufacturing process of semiconductors, MEMs, LCD screens and solar panels.

How Megasonic Cleaning Systems Work

All ultrasonic and megasonic cleaning systems work by generating cavitation bubbles in a cleaning solution. As a megasonic wave propagates through the fluid, wave troughs produce areas of low pressure where microscopic bubbles form. When the high pressure wave peak arrives, the bubbles collapse and release a substantial amount of energy. The energy from many small bubbles collapsing at the same time acts on surface contaminants of the devices being cleaned, breaking up, dissolving and removing the contamination.

As the system frequency rises, the waves are closer together and there is less time for bubbles to form. As a result, higher frequencies produce smaller bubbles and gentler cleaning action as the collapsing bubbles produce less energy. For MHz frequencies, the bubble size approaches the size of the submicron particles, but the energy released by the collapsing bubbles is small enough that it doesn’t damage the semiconductor wafer surface. It is however strong enough to dislodge the particles.

Submicron particles are hard to remove because they are small enough to be embedded in the boundary layer between the solid wafer and the free-flowing cleaning solution. Even when the cleaning solution moves quickly under pressure, the boundary layer remains static and holds the tiny particles in place. During megasonic cleaning microscopic bubbles move right up to the particles and, when a bubble collapses, the resulting energy burst dislodges the particle. The megasonic cleaning system produces a current that takes the particle away from the wafer surface and prevents it from becoming attached again.

This process effectively removes almost all particles from the surface of the semiconductor parts and results in fewer defects in the final product. Semiconductor manufacturing facilities can improve product quality and produce fewer defective products.

Megasonic Cleaning System Characteristics and Features

A megasonic cleaning system consists of a high frequency generator capable of producing MHz frequencies, a corresponding transducer and a tank to hold the cleaning solution and the parts to be cleaned. Ideally the unit can operate over a range of frequencies to let operators adjust the system to meet the cleaning performance they need. Adequate cleaning power is required and the system should not need extensive set-up and calibration.

Kaijo has extensive expertise and broad experience with ultrasonic and megasonic cleaning systems. The company can advise customers on the best cleaning methods and can help customers select the system, equipment and features best suited for their process. The Quava megasonic cleaning system is a cost-effective solution that can operate at lower ultrasonic frequencies of 26 kHz to 200 kHz as well as higher megasonic frequencies of 430 kHz, 750 kHz and 950 kHz with up to 1200 watts per generator. The company also offers the desktop compact Quava Mini system, the US Shower, the Mega Tube and the Spot Shower for additional megasonic cleaning applications. These components complement Kaijo’s range of products, allowing the company to support customers in all their megasonic cleaning applications.

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7 Things to Consider When Selecting Ultrasonic Cleaners

February 15, 2017

Ultrasonic cleaning systems can clean many parts better than other cleaning methods because of the intense scrubbing action of cavitation bubbles generated by the ultrasonic waves. While ultrasonic cleaners often work faster and clean more completely than conventional cleaners, they have to be suited for the cleaning application. Facility managers and other decision makers have to be familiar with ultrasonic cleaning system characteristics and features so they can select cleaners that perform up to expectations. Below are seven things to consider when selecting ultrasonic cleaners. Kaijo can help ensure that such considerations result in the selection of systems that will improve cleaning performance.

  1. What frequency do you need?

The frequency determines the size of the cavitation bubbles and the intensity of the cleaning action. Low frequencies down to about 20 kHz generate comparatively large bubbles for robust cleaning action to remove heavy contamination from rugged parts. Higher frequencies up to 200 kHz generate progressively smaller bubbles for more gentle cleaning of delicate components. The highest frequencies up to the MHz range can be used for cleaning fragile parts such as electronic microcircuits and medical equipment. For flexible applications an ultrasonic cleaner with multiple frequency ranges is useful.

  1. What cleaning power do you need?

While the ultrasonic frequency determines the bubble size and cleaning intensity, the system’s power in watts gives the overall cleaning capacity. Larger tanks need more power. A cleaning solution tank of about 400 by 400 mm and 250 mm deep requires about 1200 W.

  1. What size of tank do you need?

The longest dimension of the largest part to be cleaned determines the size of the tank required to clean the part. Kaijo has a variety of standard tank sizes and can build custom tanks for special requirements. If a basket is used, the part has to fit in the basket and the tank has to be slightly larger.

  1. Do you need a basket?

Baskets fit inside the tank and hold the parts to be cleaned away from the walls and tank floor. Some tanks use the bottom of the tank as a membrane to transmit the ultrasonic waves, causing parts resting on the bottom to vibrate against the tank. This can cause damage to the part and to the tank.

  1. Do you need heating?

Heating the cleaning solution can speed up cleaning and improve performance when contaminants include grease and oil that can be softened with heat. For contaminants not affected by heat there is little benefit in heating the cleaning bath.

  1. What cleaning solution should you use?

While industrial ultrasonic cleaners can work with plain water, adding mild detergents to the cleaning solution can improve cleaning performance. In some cases, slightly acidic or slightly alkaline cleaning solutions will help soften or dissolve the contaminants to be removed.

  1. Do you need sweep mode?

Sweep mode varies the ultrasonic frequency slightly around the set frequency value. For example, a system set to 38 kHz might cycle through 35 to 41 kHz in a continuous variation. Fixed frequencies result in dead spots without bubbles and hot spots with too many bubbles in the cleaning tank. Parts may resonate at a fixed frequency and suffer damage. Sweeping the frequency avoids these problems.

Kaijo can help with considerations such as these to ensure customers select the ultrasonic cleaning system that meets their requirements. Kaijo’s extensive experience in ultrasonic technology and the company’s broad range of ultrasonic cleaning equipment mean that expert advice is available to ensure the systems customers select deliver the improved cleaning performance and increased productivity they expect. If you would like a free consultation on how Kaijo’s ultrasonic cleaners can be used for your cleaning application call Kaijo or email info@kaijo-shibuya.com.

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