Design and Experimental Research of Atomizer Based on Micro Abrasive Ultrasonic Polishing Bang-fu WANG, Yin ZHEN, Juan SONG and A-chun ZHU

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1 217 3rd International Conference on Applied Mechanics and Mechanical Autoation (AMMA 217) ISBN: Design and Experiental Research of Atoizer Based on Micro Abrasive Ultrasonic Polishing Bang-fu WANG, Yin ZHEN, Juan SONG and A-chun ZHU Suzhou University of Science and Technology, Jiangsu, Suzhou, 2151 Keywords: Micro abrasive, Mist ultrasonic, Polishing. Abstract. The ultrasonic vibrator (atoizer) will play an iportant role in icro abrasive vapor ist ultrasonic polishing process. In this article, three ethods are used to design the atoizer, and the effect of atoization is verified by experient. The esh atoizer has the best effect of atoization. Study on the ultrasonic ist, the ist fored by ultrasonic atoization of the slurry containing icro abrasive has a erosive force, which can be used for polishing the workpiece surface. Polishing is perfored by eans of a ist strea fored by ultrasonic vibration with a slurry containing a icro abrasive. Specifically, the ultrasonic vibration is used to atoize the slurry containing the icro abrasive to for a vapor ist. Then, polishing is perfored with a ist containing icro abrasive. The Basic Principle of Micro Abrasive Mist Ultrasonic Polishing Method The basic principle of icro abrasive ist ultrasonic polishing ethod is that polishing slurry containing icro abrasive particles is arranged in the container which is contained in the polishing liquid, and the inner cavity of the atoizer is sucked into the atoizer through a icro pup.then, with the ultrasonic vibration of the piezoelectric ceraics, the inner cavity of the atoizer is penetrated into the surface of the nozzle, and the slurry is ejected in a for of ist. Finally, foring a ist flow with icro abrasive. The ist flow with a certain velocity is sprayed directly onto the workpiece surface together with the icro abrasive particles, and ist flow is collided with the workpiece. Therefore, in the polishing area of the workpiece surface, resulting in local area grinding, erosion and shearing action, so as to achieve the purpose of aterial reoval. Because the slurry flows very slowly in the inner cavity of the atoizer, the abrasion of the nozzle can be neglected, while the ultrasonic vibration has the function of preventing clogging, and the icro abrasive particles are prevented fro blocking the passage inside the atoizer. Vibration Equation Analysis of Ultrasonic Atoizing Nozzle Since the vibrating surface is one end of the horn (the other end of the horn is connected to the ultrasonic transducer), and each haronic point in the horn is subjected to haronic vibration, so that It is possible to assue that the aplitude of the haronic force is applied directly or through the polishing fluid to the icro abrasive indirectly. Because of the relatively short distance (generally less than 5) of the stea ist flow erosion, the work done by gravity is transfored into a relatively sall dynaic energy. Therefore, the effect of gravity on the abrasive is no longer considered in the kineatic odel of icro abrasive. Micro abrasive is subject to two forces in the course of the capaign, one is due to the ultrasonic vibration abrasive grinding force, another is the resistance of the air particle in the process of oveent by, it is proportional to the velocity of abrasive grains. If the displaceent of icro abrasive is µ, the oving speed is ν, and the daping coefficient of air is c, the equation of otion of icro abrasive is: 2 d u du + 2 sin c F ωt dt dt 253

2 type ω 2π f, f is the ultrasonic vibration frequency, substituting equation becoes the following for: du v into upper for, the dt Its particular solution is ( ) dv + cv F siωt dt v v sin ωt + φ, bring back the original equation: F v 2 2 ( ω ) + c ω φ arctan c v is the axiu velocity, and φ is the phase difference between the applied force and the applied force. The next step is to establish a link between the power of ultrasonic output and the speed of the abrasive grains, which is the relationship between ultrasonic power and the axiu velocity of the abrasive grains. Assuing that the ultrasonic power is P, the total nuber of abrasive grains to be processed in the suspension is N, and the percentage of ultrasonic power delivered to the abrasive particles to be o ω processed is η, within one second: η ( ) ( ) ( ) sin ( ω ) sin ( ω + φ ) the upper solution can be obtained: 2π P N f F t v t dt N f F t t v t dt F N fv cosφ By substituting the upper displaceent (3) forula, the axiu velocity of the abrasive particle otion can be obtained: Fro cosϕ c 2 2 ω + c 2 η P v N f cos ϕ + c ( ω ) 2 By the oentu theore, the ipact load is N fc v v v N fc F Thus, the axiu force of the icro abrasive ipact on the workpiece is achieved. [8] Because the icro abrasive is under the action of ultrasonic vibration of horn, icro abrasive has a certain speed and oentu (kinetic energy), when the icro abrasive flow to the surface of the workpiece in a certain aount of oentu, icro abrasive due to changes in oentu, resulting in erosion force on the surface of the workpiece, the erosion force will be reoved fro the workpiece aterial. 254

3 Design of Atoizer for Ultrasonic Mist Polishing The above analysis shows that the ultrasonic vibrator (atoizer) will play an iportant role in the process of icro abrasive stea ist ultrasonic polishing. The atoizer for ist ultrasonic polishing is designed based on the sandwich piezoelectric ceraic transducer in this paper. The sandwich piezoelectric transducer in the design, which is ainly coposed of a cover plate (after atching block), piezoelectric ceraic piece, the front cover (front, block) and prestressed bolt etc. In order to obtain the velocity ratio before and after the transducer front cover is ade of titaniu alloy aterials, the choice of soe heavy etals in No. 45 steel plate, it can ake the iniu energy fro the transducer surface radiation, thereby iproving the transducer to radiation efficiency, sound radiation pressure field, iprove the sound effect of sound field on the foration of ist atoizer grain. Design of Nozzle Atoizer According to the resonant frequency of 55k Hz, the longitudinal vibration electric power of atoizer vibrator is 1W, select the low dielectric loss of PZT-8 eission type piezoelectric ceraic piece, the front cover selection LY12, back with #45, the design of ultrasonic atoizer is shown in Figure 1, the priary atoizing nozzle is arranged at the front end of an ultrasonic vibration atoizer, when the electrode of the atoizer is connected to the ultrasonic electric signal, an ultrasonic vibration is generated in the oscillator portion of the atoizer, the aplitude of ultrasonic vibration is aplified at the front of the horn, and the ultrasonic radiation at a certain aplitude is generated at the secondary atoization surface. The polishing slurry with a certain pressure flows through the liquid delivery pipe to the front of the horn, after a spray nozzle of the icroporous jet and transfor the ist, the atoization surface is sprayed to the two atoization radiation surface, and the atoization is produced under the ultrasonic vibration of the atoized radiation surface.[1] Figure 1. Physical drawing. Design of an Increasing Horn Type Atoizer Figure 2. Physical drawing of ultrasonic atoizer. Ultrasonic horn is very iportant in ultrasonic technology, especially in the vibration syste of high intensity ultrasonic equipent. Its ain role is the echanical vibration of the particle displaceent or velocity aplification, in addition, ultrasonic horn can be used as a echanical ipedance converter, the ipedance atching between the transducer and the load, the ultrasonic energy ore efficiently transitted fro the transducer to the load. The ultrasonic aplitude of the transducer can be aplified fro.5 to.1 in the future fro.1 to.1, so as to increase the atoizing capacity of the atoizer and be easy to be polished. In the design of ultrasonic horn, the design ethod is used in the traditional analytical ethod and finite eleent ethod is the ost basic. 255

4 Figure 3. Longitudinal vibration odes and their natural frequencies of atoizer. Design of Mesh Atoizer Figure 4. Physical drawing of ultrasonic atoizer. In order to ensure the atoization quantity when designing, ultrasonic vibration atoizer uses low frequency pressure (2.3KHz) high power ultrasonic vibration transducer as driving source, and the atoization of the esh plate atoization ethod is adopted, and a certain aount of icropores are uniforly distributed on the front cover of the ultrasonic vibration atoizer. The icro hole in the front cover of the atoizer can deterine the quantity and the aperture of the icropore according to the requireent. Its ain function is to enlarge the particle displaceent or velocity of the echanical vibration, or to focus the ultrasonic energy on a saller area, that is, the cuulative effect. The aplitude of the horn can be aplified because the vibration energy of any cross section is constant (the propagation loss is not negligible). The energy density of the section is sall and the aplitude of vibration is greater. The ultrasonic nebulizer is shown in Figure 6. [2] Figure 5. A siulation diagra of an atoizer Ansys syste. Figure 6. A physical diagra of an atoizer. In the design process of ultrasonic atoizer, based on the wave equation of variable cross-section 256

5 longitudinal vibration theory, the relationship between the resonant frequency and the structure of the longitudinal coposite transducer is obtained, so deterine the paraeters of each part, the specific ethods and steps of any literature data are discussed in detail, here is not to dwell on [1-4]. In order to ake the processing convenient, the horn adopts 1/2 wavelength ladder type horn. Figure 5 is a siulation diagra of an atoizer Ansys syste, and Figure 6 is a physical diagra of an atoizer. Experient and Conclusion Experients on three kinds of atoizer are carried out. The effect is shown in Figure 7. Figure 7. Atoization effect chart of three kinds of atoizer. Through the atoization experient research of three kinds of ultrasonic vibration atoizer, the esh atoizer has the best atoization effect, the direction of the fog flow is good, the dispersion is not dispersed, and the oentu of the fog particle is large, and the ipact effect is good. Acknowledgeent Supported by Suzhou science and technology projects (SYG21427) References [1] Wang Bangfu, Li Hua, Yin Zhen, Cao Ziyang. Theoretical analysis and experiental study on polishing by icro abrasive ultrasonic ist[j]. Manufacturing Technology & Machine Tool. 631 (1) (215) [2] Wang Bangfu, Yin Zhen, Li Hua, Cao Ziyang, Song Juan. Technology and experiental study on polishing by icro abrasive ultrasonic ist[j]. Manufacturing Autoation. 37(2) (215) 27-3(44). [3] B.J. Koeppel, G. Subhash. Characteristics of Residual Plastic Zone under Static and Dynaic Vickers Indentations[J]. Wear. 1999, 224: [4] M. Achtsnick, P.F. Geelhoed, A.M. Hoogstrate. B. Karpuschewski. Modelling and Evaluation of the Micro Abrasive Blasting Process[J].Wear. 25, 259(1-6):