Papers by Keyword: USM

Abstract: In the previous many years, several attempts have been made to enhance the effectiveness of the Spark erosion machining process. This review clearly mentioned all the work outputs of Vibration Assisted Electric Discharge Machining at a glance. One of these non-traditional machining techniques, called electric discharge machining (EDM), produces higher surface finishes, high levels of precision, and machinability. Ultrasonic vibrations are used in many industrial processes, such as material removal operations for form generation on material surfaces. Lately, there has been an increasing trend toward using ultrasonic vibration to enhance process performance. Ultrasonic vibration finds noteworthy application in industrial processes such as spark erosion machining, where vibration is enhanced by using ultrasonic waves as a medium. The electrode's ultrasonic vibration modifies the discharge gap and improves the chip removal capability, making it a very effective technique for raising EDM efficiency. An overview of the literature on the application of ultrasonic vibrations in electric discharge machining is presented in this article. Review work has been done on how ultrasonic vibrations can be applied, their ability to affect performance metrics, how to predict and optimise processes, and how to use them with advanced materials that can be difficult to cut. Future requirements for research have been highlighted to increase the ability and potential for the technique of electric discharge machining based on an evaluation of the present state of ultrasonic-assisted electric discharge machining.

Abstract: Ultrasonic Vibration-Assisted Machining (UVA) is a machining process that adds a micro-scale high frequency vibration to the motion of a cutting tooltip to interrupt the continuous interaction of tool - workpiece surface. A good point of machining with UVA is more effective than conventional processes such as lower machining forces, higher machining stability, less tool wear and better surface finishes. In molds fabrication with some narrow cavities having a conversion space diameter of less than 3mm will face many difficulties while low surface roughness is required. Low stiffness of technological system in these cases of finishing machining is the reason of a weak machining in high-speed cutting. The ability to achieve cutting speeds for surface finishing of this type in tight spaces is also an interesting application for UVA tools. This paper discusses the finishing machining tool design with UVA for milling machine in such as analyze of the main parameters, adding diagonal split and simulation of the generated vibration effects to evaluate the achieved results before fabrication by using the help of ANSYS.

Abstract: The main objective of this experimental work is to study the effect of Hydro Fluoric acid in ultrasonic machining of polycarbonate bullet proof UL-752 and Acrylic Heat resistant BS 476 Glass. In which, mixture of abrasive particle are also used as the input machining parameter. Three types of abrasive; Alumina, Silicon Carbide and Boron Carbide are used for machining. Experiment has been performed with 8mm of high carbon high chromium tool steel (D2), high carbon steel (HCS) and high speed tool steel (HSS) tools. The material removal rate was father enhanced by HF acid. The experimentation date represent the main effect plots for tool wear rate and material removal rate. After analysis, results reveals that Al₂O₃+SiC+B₂C mixed slurry (1:1:1), Hydro Fluoric acid with 1% concentration and High Speed tool Steel material produce the higher material removal affect.

Abstract: Polycarbonate bullet proof glass and acrylic heat resistant glass are used as the functional material in many application. In this research paper, Taguchi modal is utilized for the ultrasonic machining of these material. Surface roughness is significant output parameter, because it define accuracy of the process. Taguchi modal suggest that 40% concentration, mixture of Alumina, Silicon carbide and Boron carbide abrasive in 1:1:1, 600 abrasive grit size and 1.5% HF acid gives best results in polycarbonate bullet proof glass material and for acrylic heat resistant glass, mixture of Silicon carbide and Boron Carbide abrasive in 1:1, 600 abrasive grit size and 1% HF acid gives the best results. More significant parameters contribution in surface roughness are concentration of slurry, grit size of abrasive and HF acid. Optimum parameters improved the surface roughness by 23% and 24% in polycarbonate bullet proof glass and acrylic heat resistant glass respectively.

Abstract: Studying of image enhancement shows that the quality of image heavily relies on human visual system. In this paper, we apply this fact to design a new image enhancement method for medical images that improves the detail regions. First, the eye region of interest (ROI) is segmented; then the Un-sharp Masking (USM) is used to enhance the detail regions. Experiments show that the proposed method can effectively improve the accuracy of medical image enhancement and has a significant effect.

Abstract: In this paper, a new type of cylindral USM with two stators is researched. There is a brief analysis of the USM design including mechanical structure and driving circuits. Meanwhile the paper also introduces some of the experiment results of the USM tests.

Abstract: Experiments of combining micro EDM with USM are carried out to enhance the machining ability and flexibility of the micro EDM, improve the machining state, and increase the productivity and aspect ratio of the micro holes. Basing on RC pulse power supply and workpiece vibration, the micro holes are drilled. The results of comparing experiments indicate that in the processes of both micro EDM without USM and micro EDM with USM, the machining velocity and the wear of the electrode increase with the increase of open voltage and loop capacitance. The experiment results of amplitude influencing on the machining process indicate that with the increase of ultrasonic amplitude, the machining velocity heightens and the aspect ratio of the micro holes augments; at the same time, however, the wear of the electrode and the extensive magnitude of the holes increase. Micro holes with some cross-section and accurate profile are drilled steadily.

Abstract: The paper presents a novel structure cylinder driving USM (ultrasonic motor). Through development and experimentation, the torque and rotational speed of the prototype were tested, which proves that this type of USM has a very simple structure, self-adjusting pre-tightening force and compensation for wear. The results verify the theoretical feasibility and provide instructions for the industrialization of this type of USM.

Abstract: It is necessary to drill micro holes in some hard brittle materials. Comparing with electro discharge machining, electrochemical machining and laser machining, the ultrasonic machining (USM) has unique advantages in hard brittle materials machining. The aim of this paper is to present experimental work that has been done in micro holes machining by micro USM. The main machining mechanisms of USM are discussed. It is pointed out that the contributions of each mechanism to material removal rate are different in different cases. By using micro USM with workpiece vibration and tool feeding in constant rate, the experiments of micro holes machining are carried out and the process laws of tool wear are studied. Some phenomena are found and the causation of causing these phenomena is analyzed. A Ø13μm micro hole is obtained.

Abstract: In this paper we present a multifunctional combined CNC machine that integrates the technology of USM, EDM and grinding. For non-conductive hard and brittle materials, the machine tool could perform ultrasonic machining and grinding machining combined ultrasonic vibration; for conductive hard and brittle materials, electrical discharge with or without ultrasonic vibration could be implemented. Conductive engineering ceramics have been used for elementary experiments, the results show that it is more efficient and more stable for processing this kind of materials by using the multifunctional combined CNC machine. On the basis of brief introduction about the structure of the machine tool, this paper emphasizes the form of control system, the gap state inspection that can be used to ensure the stability in processing and the principle for servo control.