Optimization Of Horn And Experimental Study For Near Field Acoustic Levitation

In the field of precision and ultra-precision machining field, such as in the semiconductor industry, there are increasingly stringent requirements in product surface finish and cleanliness of the working space. Particularly in wafer clamping and transport project, the traditional clamping technique will damage to the wafer surface and affects the cleanliness of work space. Based on the above issues, explore non-contact clamping becomes new research direction. Near field acoustic levitation for short NFAL is a phenomenon that using high energy density acoustic radiation pressure and gravity balance objects. However, the near field acoustic levitation technology is not yet mature, such as there is no unified theory of sound pressure distribution, and instability in the suspension process. In order to get stable sound field, this article improved the ultrasonic horn, mainly research are as follows:Using the frequency equation homogenization section bars and thin disk, to preliminary design of the horn, and using finite element simulation, To obtain the vibration frequency of around 20kHz horn size.Using methods of removing material from horn to get optimal sound field and make a theoretical analysis of shapes and sizes for the removal of materials are.Analysis of the distribution of the sound field sound pressure based on the sound pressure measured at the surface of the horn. By increasing the distance between the object and the vibrating surface of the disk to weaken the higher sound pressure of the central region. Obtaining more equal sound pressure of vibration disk surface peak by removing material. To determine the diameter of removing material by use sound pressure higher than the average in the central region of horn. Using relationship between sound pressure and height in the near field region and standing wave suspension to determines the depth of the hole. Giving the influence of the shapes and sizes for the removal of materials to the vibration frequency of the ultrasonic horn.Two improved horns are obtained by removing material and make compare experiment with the traditional horn. Experiment study on the sound pressure distribution, suspension height of the object and the object being suspended the revival period of the experiments.Experiments on the suspended objects by the traditional horn. Study the effects of different diameters of suspended objects on the suspension stability and the influence of the suspension height of different roughness, materials and surface quality.