CREST 기술

An In Depth Look At The Advantages Of Crest's Patented Ceramically Enhanced Transducer Technology.

By J. Michael Goodson, CEO Crest Ultrasonics, Chairman of The Board, The Crest Group Inc.

Firstly, I feel it would be best to first introduce some of the results our cermically enhanced transducer technology have fostered in a few of our client's production environments:

• A disk media manufacturing facility cut its process time in half and got the cleanest disks ever.
• Another disk media manufacturing facility improved its yield by 4%. The equipment pays for itself in 79 days.
• A slider tab application increased yield to 100%.
• A military application using solvent improved process time by 40%.
• An Asian solvent/alcohol application for cleaning & drying produced the highest HSA yield ever recorded, with submicron specifications.

Our discovery of the ability to substitute acoustically superior high-tech ceramics for metals in stacking transducers is perhaps the most important development in ultrasonics in the last 30 years. The high-tech ceramics transmit sound better than even the latest state-of-the-art metals used in traditional transducers. Ceramically stacked high frequency transducers are desig ned to meet the needs of high-tech applications where the requirements are submicron cleaning. They offer superior transmission of sound at higher frequencies which results in better contaminant removal and reduced damage to sensitive parts. Both general and critical cleaning applications benefit from this advanced technology.

The superiority of chart A over chart B is clearly evident. High-tech ceramics make possible the direct stacking of high frequencies that before were only available as subharmonics of metal stacked frequencies (which derive their primary power from the weaker first harmonics). The stacking of a ceramic transducer to the exact frequency results in a significantly increased level of activity.

Also note that even with a third harmonic direct stacking, the Crest first harmonic (40 kHz) is stronger than the competitor's metal stacked 40 kHz.

Ceramics Transmit Sound Better.

The acoustical speed at which sound travels through high-tech ceramics is 63% to 125% greater than aluminum, stainless steel or titanium.

Acoustical Index:

The acoustical speed at which sound travels through high-tech ceramics is 63% to 125% greater than aluminum, stainless steel or titanium.

The problem with traditional metal stacked transducers is that solid metal is actually made up of strands and strands of metal, which under high magnification is actually quite porous. In the transmission of sound waves, the porosity becomes very significant.

High-tech ceramics like alumina oxide and silicon carbide have a composition of molecules so minute, the porosity is near zero. Their surfaces are so flat they can be measured in 1,000,000 of an inch. As a result they offer superior acoustical speed and an improved surface interface. Thus stacking an ultrasonic transducer with ceramics greatly enhances the transmission of ultrasonic energy. The near perfect transmission of sound also reduces the amount of stress involved with transmitting ultrasonic energy, resulting in increased day-to-day reliability and a much longer trouble-free life for the system in use.

Stacking Transducers With Ceramics.

Taking into consideration the acoustic superiority, transmitting sound into the ceramic resonator directly before the aluminum head mass results in more sound waves being transferred and with greater intensity.

The ceramic interface allows for the near-perfect transmission of sound.

What is a third harmonic frequency?

Piezo Ceramic Crystals (PZTs) used for creating ultrasonic energy are known by their first frequencies, the traditional Crest 40 kHz PZT for example (see chart 1). Expand the chart and you see an even stronger third harmonic frequency (chart 2). Looking at the chart's full spectrum, you will see a number of different harmonics (see chart 3). The harmonics are based on the number of signals that can be readily identified with some subjective expectations of strength which makes them useful. High-tech ceramics make possible the direct stacking of high frequencies that were previously only available as sub-harmonics of metal stacked frequencies (which derive their primary power from first harmonics). Third harmonics are always stronger than first harmonics. Therefore the direct stacking of third harmonics is highly desirable. Fifth and higher harmonics also offer good potential for future development.

The first harmonic is 40 kHz (Chart 1).
But when you expand the chart, notice the stronger third harmonic (Chart 2).

If you do a complete scan of the 40 kHz PZT you can see a total of six (6) strong harmonics, with 40 kHz (the first harmonic ) being the weakest. The advantage of being able to directly stack harmonics other than the first gives the user of ceramic stacked transducers a big advantage. Metal stacking works off the weakest harmonics.

How Many Third Harmonic Possibilities Are There For High Frequencies?

Is it possible to create a third harmonic frequency at any point between 100 and 350 kHz? Yes, you can create third harmonics up to 500 kHz but it would be cost prohibitive for the end user, as you go above the 325 to 350 kHz range.

Is The Ceramic 132 kHz The Universal Transducer Of The Future?

No. It is a great third harmonic frequency, but with ceramic stacking you have the luxury of having a family of third and higher harmonics designed to meet specific needs.

The Ceramic 200 kHz.

This new introduction will challenge the megasonic frequencies and their modest intensity. Like other third harmonics,
it is extremely intense for such a high frequency. With the ceramic intensity, it is likely to replace many of the megasonic units on the market. Reliability: Using the Martin Walter power supply we expect the transducers to last for several years compared to most megasonic transducers' life expectancy of 6 to 12 months.

How Reliable Are Ceramic Transducers?

After more than 18 months since its introduction, and with more than 75 ceramic 132 kHz systems installed world wide, not one single generator/transducer installation failure has been reported anywhere in the world. It seems unbelievable, but it is true. This reliability can be directly attributed to the enhanced efficiency of transmitting ultrasonic sound waves using high-tech ceramics and state-of-the-art Martin Walter AG power supplies to power the transducers.

Rigibot automation systems now feature the exclusive safety arm trigger switch assembly.

안전보호장치

Rigibot은 바스켓에 피세척물을 담아 상하 좌우로 움직일 수 있으며 Safety Arm Trigger Switch Assembly는 일종의 Interlock 장치입니다. 예를 들면 Rigibot이 바스켓을 들고 좌로 움직이다가 심한 저항을 받거나 뜻하지 않은 장에물에 부딪쳤을 때 움직임이 바로 STOP할 수 있게 만든 안전 장치 입니다.

Safety protection

Due to the variables of human error, it's impossible to eliminate this type of occurrence altogether, so the technical strategy is to greatly minimize the damage of impact. Our remarkable safety arm trigger switch is designed to detect force that results from arm contact with an obstacle, and to signal the PLC to stop the Rigibot immediately so that a correction can be made. Force detection is omni-directional, which means that contact with virtually all obstacles will be detected.