Papers by Keyword: ECM

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: The non-conventional cutting of electrically conductive materials using WEDM and WECM and their hybrid processes is already standard in manufacturing technology. This is essentially based on homogeneous or layered materials. In the future, cellular, wool-like, or similarly structured materials will play a greater role and will be more important; especially the cutting in conjunction with homogeneous materials. In the study, experiments were carried out with a standard WEDM system and a WECM test system. In preliminary tests, various EC machine structures with different flushing and cutting directions have been tested, and because of the static wire arrangement, adjustments to a maximum working current have been tried out. Various feed speeds have been implemented for the test series and the influence of the wool structure on the regulation of the short circuits in the working gap has been analyzed. A modified equivalent circuit diagram has been created from the special features of the processing. The process regulation must be adapted to the special conditions of the spontaneous working gap reduction and thus the higher number of soft short circuits. The study should primarily show where the deviations of the WEDM and WECM from wool structures are; which changes have to be made, especially for process regulation. Secondarily, it was determined which cutting structures arise and whether the partial discharges have a marginal effect on the cutting result in both processes.

Abstract: Engineering change management (ECM) affect to cost that are generated during the designing and manufacturing process. ECM also affects to the time how fast the product is on market. The changes have to be made quickly and the notifications of the changes have to reach the person who may need the information. Product Data Management (PDM) is the system which is not only storage place for the data; it is a tool which should make ECs faster and more effective. This paper deals with the techniques that are in use to handle the ECs with the help of PDM system.

Abstract: Electrochemical machining (ECM) is an appropriate technology for structuring a wide range of metals and alloys independent of their mechanical properties. Further advantages the occurence of no tool wear and almost no change in the material properties of the work piece material due to the machining. As different studies showed it is possible to manufacture structures in the µm-range and also in the sub µm-range. The resulting geometry and feature size depend on the electrolyte, the working gap, the electric field, the flow conditions within the working gap and the material structure. The working gap is the most important parameter regarding the critical dimensions of ECM. Actual high resolution processes are limited by the process time due low current densities, while faster processes are limited by the resolution due to the dimensions of the double layer and the need for purging.\\Regarding these limits an enhanced understanding of the electrochemical processes within the working gap is mandatory for the optimization of the ECM. Therefore a measurement device is realised utilising electrochemical impedance spectroscopy (EIS), which is one technique to obtain a wide set of thermodynamic and kinetic parameters related to the electrochemical processes like reactions, adsorption, desorption and diffusion in the gap. There the impedance, which is the complex ratio between the voltage and the current in an AC circuit, is measured as a function of the frequency and it is compared to an equivalent circuit, composed out of basic elements representing the chemical sub processes. The spectrometer is realized by combining a commercial potentiostat with computer based signal processing realized in MATLAB\copyright. The spectrometer implements time-domain measurement techniques (Fourier transformation) for a strong reduction of measurement time. This time reduction allows in situ measurements.\\The presented spectrometer enables characterization of standard material systems like cooper, as well as the identification of the time-critical chemical processes and steps in more complex systems.

Abstract: This study adopted ECM to explore the effect of sense of community (SOC) on learners continuance intention towards online language learning. It is proved that the continuance intention is dependent on the SOC, perceived usefulness and satisfaction.

Abstract: A rapid quality detection system for micro hole fabricated by electrochemical machining (ECM) is proposed by studying on the optical features of micro hole. The edge of micro hole is detected exactly with the digital image processing techniques, such as, the middle value filter, the threshold value transformation, and so on. The least square circle fit arithmetic and the new roundness measurement algorithm are synthetically used in the processing of geometric feature recognition of micro holes. The practical results prove that the method with exact conclusion and high precision can satisfy the quality inspection requirement of micro holes fabricated by ECM.

Abstract: The paper applies the Holt-Winter non-seasonal model to predict carbon dioxide emissions in the next five years and finds a rising trend. Then, through establishing a VAR model bases on the Granger causality test between carbon dioxide emissions and energy consumption, the application of the Johansen cointegration test finds that there is a long-term equilibrium between carbon dioxide emissions and energy consumption. This long-term equilibrium plays an “adjusting” role in the process of balancing dioxide emissions and energy consumption. It is obvious on the adjustment effect from short-term fluctuations to the long-term equilibrium. Finally, this paper puts forward corresponding policy proposals for China's low-carbonization of energy consumption.

Abstract: The analysis of the ECM model expressed by an equivalent circuit is helpful to understand the ECM characteristics, such as the removal rate and machining accuracy. However, the parameters in the ECM equivalent circuit have not been determined yet, although several kinds of equivalent circuits were proposed. In this research, the parameters of the ECM equivalent circuit were determined experimentally, and the determination reliability was discussed.

Abstract: In ECM process, insulating by-products exists in the inter-electrode area. These by-products disturb the current flow between the tool and workpiece electrodes, and thus affect the machining accuracy. As one of the ways to remove the by-products, a method was proposed to apply ultrasonic vibration to the tool electrode. However, the influence of the electrolyte concentration and the effect of ultrasonic vibration on the machining characteristics of the WC alloy have not been investigated yet. Therefore in this study, these influences were experimentally investigated. It was found that the machining accuracy is increased by using the low concentration electrolyte. Also, machining of the tungsten carbide (WC) alloy when applying the ultrasonic vibration to the tool electrode becomes possible.

Abstract: An electrochemical machining (ECM) manufacturing system with a reconfigurable manufacturing system (RMS) is proposed for machining materials with high hardness and with unique contours or specific edge geometries that are normally unobtainable by conventional machining methods. In the manufacturing industry, ECM systems must usually be custom designed to meet customer needs. An RMS reduces engineering time and production costs by enabling rapid and cost-effective conversion of manufacturing machines, systems, and controls in response to the market changes or customer demands. This study proposes a design method for constructing a hierarchical structure control module for synchronously reconfiguring controls and machining characteristics in a reconfigurable machine tool.