Technical Papers
Advances in Megasonic Generator Technology
By Ben Johnson and William L. Puskas
Liquid-borne acoustic energy in the frequency range between 350kHz and up to about 5MHz is finding growing usefulness in a number of cleaning applications which require processing of extremely delicate parts and assemblies to remove particles ranging from a few microns down to a fraction of a micron in size. This “megasonic” energy varies from the traditional “ultrasonic” energy in that the frequency of operation is more than an order of magnitude higher than that of a conventional ultrasonic system. Just as in an ultrasonic system, a megasonic system requires a source of electrical energy at the operating frequency of the driver or “transducer” to power the sound producing device. This source is the “generator.” New developments in generator technology by Blackstone-NEY Ultrasonics promise to improve the efficiency and reliability of megasonic generators while reducing their size. The new generator technology will also make it possible to operate transducers efficiently at more than one frequency thereby extending their process effectiveness.
Read the entire paper online on a single page | download this paper in Adobe Acrobat (PDF) format. (115 KB)
Ultrasonic Cleaning: Fundamental Theory and Application
By F. John Fuchs
A presentation describing the theory of ultrasonics and how ultrasonic technology is applied to precision cleaning. This presentation will explore the importance and application of ultrasonics in precision cleaning along with explanations of ultrasonic cleaning equipment and its application. Process parameters for ultrasonic cleaning will be discussed along with procedures for proper operation of ultrasonic cleaning equipment to achieve maximum results.
Read the entire paper online on a single page | multiple pages. Or download this paper in Adobe Acrobat (PDF) format. (281 KB)
Application of Multiple Frequency Ultrasonics
By F. John Fuchs and William L. Puskas
Selection of the proper frequency for an ultrasonic cleaning process and the use of more than one
ultrasonic frequency in a single process have been identified as important variables in many
ultrasonic cleaning applications. Ultrasonic cleaning effectiveness is enhanced by the use of the
proper frequency or multiple frequencies. Recent advancements in ultrasonic hardware offer the
user several hardware alternatives when more than one frequency is required in a process. This
paper explores the hardware alternatives for producing multiple ultrasonic frequencies and their
relative merits. Although three frequencies are used for illustration here, the concepts discussed here may be applied to any number of frequencies.
Read the entire paper online on a single page. Or download this paper in Adobe Acrobat (PDF) format. (281 KB)
Ultrasonic Cleaning: Fundamental Theory and Application
By F. John Fuchs
A presentation describing the theory of ultrasonics and how ultrasonic technology is applied to precision cleaning. This presentation will explore the importance and application of ultrasonics in precision cleaning along with explanations of ultrasonic cleaning equipment and its application. Process parameters for ultrasonic cleaning will be discussed along with procedures for proper operation of ultrasonic cleaning equipment to achieve maximum results.
Read the entire paper online on a single page | multiple pages. Or download this paper in Adobe Acrobat (PDF) format. (281 KB)
Designer Waveforms: New Ultrasonic Technology
By William L. Puskas and Timothy Piazza, Ph.D.
There are many ways to alter the characteristics of ultrasonic waves in a liquid contained in a tank. The ultrasonic waves can be frequency modulated by varying the output frequency of the ultrasonic generator. The ultrasonic waves can be amplitude modulated by changing the amplitude of the generator output and/or by tailoring the impedance versus frequency characteristics of the transducer array. A frequency modulated ultrasonic wave can be amplitude modulated. This is the most general case of "designer waveform" for a single generator driving a single transducer array. Multiple generators of different frequencies can drive multiple transducer arrays on the same tank; the addition of the resulting sound waves within the liquid creates the "designer waveform".
This paper will attempt to catalog the most useful, newest and theoretically interesting of the many ultrasonic waveforms that can be produced in an ultrasonic tank. Where appropriate it will give the history of the waveform, a practical description of its function and suggestions of where it may be advantageous, or in some cases, destructive. Empirical data supporting the theory is left for a future paper.
Read the entire paper online on a single page | multiple pages. Or download this paper in Adobe Acrobat (PDF) format. (501 KB)
The Ideal Ultrasonic Parameters for Delicate Parts Cleaning
By Timothy Piazza Ph.D. and William L. Puskas
The various ultrasonic parameters, or degrees of freedom, available to the process engineer define what the ultimate limits are for the cleaning process. The traditional degrees of freedom available in an ultrasonic cleaning system have included modulation of a single center frequency (sweep), variable duty cycle, and amplitude control at a single frequency. All of these variables allow control of gross, or macroscopic, variables such as raw power into the fluid. The latest class of aqueous cleaning technology allows all of the fore mentioned parameters, but at multiple center frequencies in a single process tank. Multiple center frequencies allow precise microscopic tuning of the energy in the individual cavitation event. Understanding and optimizing the parameters yields maximal cleaning efficiency with minimal substrate damage. Unlike much of popular ultrasonic papers available, the descriptions here are fully referenced and arrived at through sound physical reasoning. This paper intends the ambitious task of illuminating the various physical effects of these parameters in such a way as to shed as much light and as little heat as possible on this often less than intuitive subject. It is the authors' desire that this paper is not a final description, but the beginning of a dialog.
Read the entire paper online on a single page | multiple pages. Or download this paper in Adobe Acrobat (PDF) format. (593 KB)
Magnetostrictive Versus Piezoelectric Transducers For Power Ultrasonic Applications
By F. John Fuchs
There are two fundamental transducer designs used for power ultrasonic applications today, magnetostrictive and piezoelectric. Piezoelectric transducers utilize the piezoelectric property of a material to convert electrical energy directly into mechanical energy. Magnetostrictive transducers utilize the magnetostrictive property of a material to convert the energy in a magnetic field into mechanical energy. The magnetic field is provided by a coil of wire which is wrapped around the magnetostrictive material. Both types of transducers have advantages and disadvantages. Blackstone~NEY Ultrasonics has weighed both technologies and chooses to provide piezoelectric transducers. This article will help the reader understand the rationale behind this choice.
Read the entire paper online on a single page | multiple pages. Or download this paper in Adobe Acrobat (PDF) format. (151 KB)
Ten Steps To Better Rinsing
By Bill Yates
Take ten minutes and learn how to improve rinsing while reducing water consumption as much as 90 percent. (This article appeared in the December, 1991 edition of Products Finishing magazine. By Bill Yates, President, Poly Products Corp. Atwood, California.)
Read the entire paper online on a single page | multiple pages. Or download this paper in Adobe Acrobat (PDF) format. (92 KB)
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