Papers by Keyword: Ultrasonic Vibration

Abstract: Ultrasonic vibration deep hole drilling is a kind of new technology for combining ultrasonic vibration with deep hole drilling. This paper mainly describes the transformation of lathe, vertical milling machine and vertical machining center by bits vibration direction or adding some auxiliary institutions, then make it have the ability of drilling deep hole. With these transformation, machine tools have some advantages, such as the efficiency and precision are improved, machining quality is stable, chip removal is easy, the cost is low. Besides, it also provides a good way for making full use of existing equipments.

Abstract: In this paper, samples were prepared by power ultrasonic on molten Al ingot. The results show that microstructure of the samples treated by untrosonic vibration is more finer than that of the untreated ones, the ultrasonic treatment time is not the longer the better. When the vibration head dipped into the middle of the melton, the better grain refinement effect can be gotten. Too deep or too shallow of the vibration head dipped in, vibration effect just limited to near the head, the influence is relatively small when the melton far away from the vibration head.

Abstract: The mathematical models of the dynamic grinding force and the average grinding force were established by introducing the unit grinding force F_u. And the formula of the average grinding force in the grinding zone was derived. The experiments were conducted in the traditional grinding (TG) mode and tangential ultrasonic vibration grinding (TUAG) mode. The results show that the unit grinding force in TUAG is lower than that in TG in the same machining condition; the grinding force ratio is decreased due to the tangential ultrasonic vibration of the workpiece. It is helpful to improve the machinablity of the hard-brittle material.

Abstract: In this work, machining test was carried out in various machining conditions using ultrasonical vibration capable CNC machine. For work material, alumina ceramic (Al2O3) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonical vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20kHz was generated by HSK 63 ultrasonic actuator. On the other hand, grinding forces were measured by KISTLER dynamometer. And an optimal sampling rate for grinding force measurement was obtained by a signal processing and frequency analysis. The surface roughness of the ceramic was also measured using stylus type surface roughness instrument and atomic force microscope (AFM). Besides, the scanning electron microscope (SEM) was used for observation of surface integrarity.

Abstract: The current study is presented into the investigation of the application of ultrasonic vibration on the lower punch during compaction process of powder metallurgy material. The lower punch is specifically designed of ultrasonic horn which has been tuned at frequency of 20 kHz and vibrates in longitudinal mode. Finite Element modeling was used to assist the design process of the lower punch or horn. The horn was fabricated using high grade aluminium alloy and mounted onto the ultrasonic system test rig and subsequently tested prior the experimental process begins. Various static and ultrasonic compaction procedures have been carried out to confirm the capability of the tool to operate. The compaction force was reduced significantly at the onset of ultrasonic vibration applied compared to without ultrasonic.

Abstract: Poly (vinyl alcohol) (PVA), a classical biodegradable polymer, is successfully fabricated into nanofibers via the vibration-electrospinning, and the obtained nanofibers are characterized by the scanning electron microscopy (SEM). The viscosity and electrical conductivity of PVA solution vary dramatically with the ultrasonic radiation time and intensity. The novel strategy can produce finer nanofibers than those obtained without ultrasonic vibration.

Abstract: Weakness of electrospun nanofiber has impeded its industrial applications for a long period. Our studies reveal a promising solution to this problem by applying ultrasonic vibration to the polymer solutions during electrospinning. To well understand and control of this new technology, a mathematical model is much needed. During the vibration, heat and vibration induced by the ultrasonic energy will not only affect the rheological properties of the polymer solution and the energy balance of the electrospinning system, but play an important role on the current generated in the charged jet. Taking consideration of such impacts of ultrasonic vibration, governing equations for current, momentum and energy are derived, and a simplified model is also provided for practical applications.

Abstract: In this paper, ultrasonic vibration turn-milling machine tool has been designed based on the analysis of processing principle . CATIA is used to generate three-dimensional solid model for the overall layout structure of high speed miniature lathe, while finite element analysis software is used to achieve dynamic performance analysis, so as to obtain each factorial of machine-tool vibration and natural frequency. The results are important to machine optimization and the construction of experimental prototype, and will guide the next work.

Abstract: Aims at the performance of the oil distribution plate parts with laser direct rapid forming, and referring to the role of ultrasonic vibration in areas such as casting, welding, sintering etc. , and utilizing the neural networks and the genetic algorithm to optimize the process parameters, the article does the basic research of laser direct rapid forming distribution plate parts based on the ultrasonic vibration. The results indicates that this study can greatly enhance the wear resistance, the corrosion resistance and the fatigue properties etc. of the laser sintering distribution plate parts, having a good guidance to the practical production.

Abstract: For a purpose to improve electric discharge machinability of PCD composed of coarse (25μm) diamond particles, which has been thought to be extremely difficult to EDM, in this study, a method (US-EDM) to give an ultrasonic vibration to an electrode in axial direction, flexural direction and complex direction that couples axial and flexural directions was attempted. As a result, it was found that EDM efficiency could be improved to 6 times higher (0.065mm³/min) than a standard efficiency (0.011mm³/min) obtained in machining conventional PCD (C-PCD) and the electrode wear could be reduced to 1/2 by giving vibrations to the electrode in axial direction (frequency f=28kHz, amplitude δ=18μm). Further, this method (US-EDM) was applied also to a new PCD (EC-PCD) composed of electrically conductive diamond particles. As a result, it was made clear that EDM efficiency could be improved to 0.22mm³/min. This value is equivalent to approximately 5 times higher efficiency obtained in the machining of ordinary die steel and cemented carbide materials.