Papers by Keyword: Ultrasonic Vibration

Abstract: The interface between the body and recovery insulation in factory joints is susceptible to localized electromechanical weaknesses, potentially compromising the long-term reliability of high-voltage direct current (HVDC) submarine cable systems. This study introduces ultrasonic vibration into the insulation recovery process of these joints. The effects of ultrasonic treatment are evaluated through tensile tests, thermal elongation tests, DC breakdown tests, and space-charge characterization. Results demonstrate that ultrasonic treatment significantly enhances interfacial tensile properties, improves deformation stability under thermal loading, increases the DC breakdown strength of the insulation interface, and significantly suppresses negative space-charge accumulation. These improvements are attributed to the high-frequency acoustic pressure and localized temperature rise induced by ultrasonic vibration, which promote molecular-chain melting and rearrangement, thereby reducing microscopic defects. This study provides an innovative method for the insulation recovery forming process in factory joints to improve interfacial reliability.

Abstract: The effectiveness of ultrasonic vibration polishing, a polishing method in which an abrasive wheel is vibrated perpendicular to the polishing direction, was investigated. A 3mm diameter cBN abrasive electroplated wheel (#800) was used as the abrasive wheel, and it was vibrated at a frequency of 38kHz and a maximum amplitude of 5.0µm (0-p). Truncation was also performed to make the abrasive grain height of the wheel uniform. Two types of truncation were performed: film lapping and PCD lapping, and the effects of truncation were investigated. Polishing experiments were performed on SKH51, and a comparison was made with conventional polishing and the effects of truncation. The results showed that ultrasonic vibration polishing using a truncated wheel improved the polishing efficiency and surface roughness.

Abstract: The impact of heat treatment on the mechanical characteristics and microstructure of an ultrasonic vibration metal inert gas (MIG) weld is examined in this study. The findings show that the heat treatment method has a significant influence on the mechanical characteristics and structure of the welding specimens. The annealing will increase the grains’ size, thereby reducing the hardness and increasing the ductility of the joint. Due to the impact of ultrasonic during welding, the microstructure in fusion zone of both annealed and non-annealed specimens showed small and fine grain structure (with the grain size being measured at less than 40µm). The result also demonstrates that during annealing, the carbon tended to diffuse from the area of high density to the region of low density, resulting in a reduction in hardness compared to the initial sample. Also, it was discovered that elements that lower weld strength (such as the irregularity of the grain structure and the dendritic structure produced by metal crystallization) significantly decreased.

Abstract: 7075 aluminum alloy is widely used due to its great performance, especially in aerospace area. In this paper, ultrasonic-assisted grinding technology is used to process 7075 aluminum alloy. The data is obtained through experiments, and the surface roughness and morphology of ultrasonic assisted grinding and conventional grinding under different spindle speeds, feed rates, and amplitudes are analyzed. Research has found that the increase in spindle speed and amplitude will improve the quality of the machined surface and reduce the surface roughness by 82.1% and 36%. However, with the increase of feed rate, the surface quality decreased significantly, and the surface roughness increased by 55.6%. The surface micro-morphology of the machined workpiece is observed, and the effects of different processing parameters on the surface micro-morphology are obtained.

Abstract: In this paper, through a series of grinding experiments with different machining parameters on the surface of the workpiece, the surface roughness under different machining parameters are obtained The surface roughness prediction model is constructed by the response surface method. The effects of feed rate, amplitude, and spindle speed on the surface roughness are analyzed. The results show that the surface quality of ultrasonic-assisted grinding is better than that of conventional grinding. Amplitude has the most prominent effect on the improvement of surface quality, followed by the spindle speed. The feed rate has little effect on the surface roughness. The model can predict 93.71% of the experimental results and the prediction error of the model is lower than 5%.

Abstract: Cemented carbide has huge applications in industrial production, but its high mechanical properties also increase the difficulty of processing. In this work, ultrasonic vibration-assisted grinding technology is used for the precision manufacturing of cemented carbide. The influence of the dynamic trajectory of the grains on the material removal process is analyzed. The morphology and roughness of the processed surface are measured and studied. It was observed that in the conventional grinding, the blade pattern is obvious with some defects on the surface. While in the ultrasonic vibration-assisted grinding, the material surface is mainly distributed with pits and small protrusions, and there is no obvious blade pattern. According to the roughness test, the roughness of ultrasonic vibration-assisted grinding is better than that of conventional grinding, and the increase in amplitude has a significant effect on the improvement of roughness. When the amplitude increases from 3μm to 9μm, the surface roughness is improved about 38.1%. The research of ultrasonic vibration-assisted grinding should be of great importance for promote the high-efficiency and high-quality processing and special applications of cemented carbide.

Abstract: Inconel718 has been widely used in various fields for its good performance, but it is difficult to machine with traditional machining methods. Electrical discharge machining is an alternative competitive process to machine Nickel-based alloys by electrical erosion. In order to improve reduce the electrode loss and improve the machining efficiency, the horizontal ultrasonic vibration of the workpiece and the cryogenic cooling of the tool electrode were applied into the EDM process. Material removal efficiency, surface roughness, surface topography, and microhardness have been characterized.

Abstract: This paper present an investigation on cutting speed of ultrasonic vibration assisted wire electrical discharge machining (US-WEDM) for High carbon high chromium D3 Steel. An extensive research study was carried out with an aim to select the optimum cutting condition with the varying amplitude of vibration in order to get the optimum cutting speed for the proposed set-up. The process was mathematically modeled using the response parameters, i.e. cutting speed under a range of control parameters and the main influencing factors were determined for cutting speed criteria Taguchi’s experimentation methodology indicated the contribution of amplitude of vibration (P=6.16%), pulse on time (P=14.54%), pulse off time (P=73.16%) and peak current (P=5.94%). Finally, the optimum parametric setting for different cutting speed arising out of study has synthesized as amplitude of vibration at level 3 (18μm), peak current level 1 (100 units), pulse on time level 2 (118 μ sec) and pulse off time level 2 (46 μ sec) and analyses in this study.

Abstract: This article analyses the process of occurrence of the surface roughness during the ultrasonic hobbing of the fine pitch gears from the viewpoint of the theory of elastic-plastic contact, and suggests analytical solutions and regression equations to estimate the roughness parameter Ra in both conventional and ultrasonic machining.

Abstract: This article investigates the impact that the rake and rear faces of the drill made from high-speed steels of grade P6M5 and grinded by ultrasonic techniques imposes on the roughness of the holes being machined. The experiment showed that microgeometry of the tool sharpened by transmitting ultrasonic impulses into the zone of regrinding featured lower roughness; moreover, roughness parameters of the drilled holes were also improved.