Active gap capacitance electrical discharge machining of polycrystalline diamond

Wang, Xiangzhi; Yi, Shuang; Easton, Mark; Ding, Songlin

doi:10.1016/j.jmatprotec.2020.116598

Cited by 25 publications

(9 citation statements)

References 28 publications

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“…It can be seen from equation ( 2) that the value of the capacitor used in the RC circuit has an important impact on the discharge energy, 69 which plays a significant role in the improvement of MRR. 70 Several approaches have been developed to improve machining efficiency based on the capacitance of the discharge circuit, for example, explosive electrical discharge grinding (IEEDG) 71,72 and active gap capacitance EDM (AGC-EDM), 73,74 whose equivalent circuit is shown in Figure 7. In the two methods, the capacitances involved in the EDM process were increased.…”

Section: Dominant Factors In Removing Materialsmentioning

confidence: 99%

Electrical discharge machining of polycrystalline diamond: A review

Wang

Guo

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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Owing to its ultra-hardness and exceptional wear resistance, polycrystalline diamond (PCD) is widely used in numerous applications such as bearing, nozzle, metal cutting, oil and gas, and hard rock mining. However, the hardness of diamond means PCD products are incredibly difficult to manufacture. Electrical discharge machining (EDM) is one of the most effective non-traditional methods used for machining PCD materials, although the unique composite structure and low electrical conductivity of PCD lead to low machining efficiency. This paper presents an overview of the methods and newly emerged state-of-the-art technologies to improve material removal rate and surface quality as well as the mechanisms behind these methods. Literature analysis shows that efficiency improvement could be achieved by increasing energy utilization and the sparking gap in EDM. The utilization of discharge energy is highly sensitive to the expansion of single discharge sparks. Further improvement in machining efficiency could be achieved by enhancing discharge expansion and explosive force through changing processing forms, dielectric, electrode shape, and power generator in the future. To provide a comprehensive insight of the machinability of PCD, EDM processes of using PCD as tool electrodes to machine other materials to improve machining performance are also discussed.

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Section: Dominant Factors In Removing Materialsmentioning

confidence: 99%

Electrical discharge machining of polycrystalline diamond: A review

Wang

Guo

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…Electrical discharge machining (EDM) is one of the most widely used non-conventional machining methods which has been extensively applied in the industry to the machine hard and electrically conductive difficult-to-cut materials since its invention in the 1940s [1]. In the EDM process, workpiece materials are removed by the heat generated by a large number of recuring electrical sparks occurring at high frequency in the small gap between the tool electrode and the workpiece [2][3][4]. Since EDM is a thermal machining process in which the tool electrode and workpiece have no physical contact with each other, chatter, vibration and mechanical stress, which are the common challenges encountered in conventional computer numerical control (CNC) machining processes, are thoroughly eliminated [5].…”

Section: Introductionmentioning

confidence: 99%

The state of the art of electrical discharge drilling: a review

Mao

Almeida

et al. 2022

Int J Adv Manuf Technol

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Electrical discharge machining (EDM) is one of the most widely used non-conventional methods to machine electrically conductive materials in the manufacturing industry because of its strong capability in machining difficult-to-cut materials irrespective of their strength and hardness. Electrical discharge drilling (EDD) is an important variant of EDM. Due to the limitation of conventional drilling processes, special holes, particular those with high aspect ratios on hard-to-cut materials, can only be drilled by EDD. Extensive research has been carried out to improve the efficiency and quality of the EDD process by using different approaches, such as assisted EDD and powder-mixed EDM drilling aiming to improve the material removal rate (MRR), tool wear rate (TWR), surface quality and accuracy. This paper provides a comprehensive review of the EDD process. Different methods were compared; the advantages and disadvantages of each process were summarised; state-of-the-art technologies and the latest development were introduced, and research trends and new directions were presented.

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“…As the intensity of the electric field increases, electrons are conducted to the surface of the workpiece to form a loop. Wang et al [4] proposed that when EDM processed PCD, there was a graphene film on top of the PCD, and the discharge point was not restricted by the metal binder or limited to conductive materials (which was the case of conventional EDM). The discharge point could work on any surfaces of the piece theoretically.…”

Section: Introductionmentioning

confidence: 99%

Development of an On-Line Defect Detection System for EDM Process

Lyu¹,

Jan

Ay³

et al. 2022

Applied Sciences

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In the electrical discharge machining process, preliminary research has been able to effectively estimate machining accuracy in response to its long machining history and high discharge frequency characteristics. However, when processing abnormalities occur, it is difficult to identify them since the electrical discharge process contains multiple processing parameters, which increases the cost of repair or loss afterwards. Therefore, the question concerning how to monitor the abnormality of the discharge process in real time represents the main purpose of this research. This research develops an EDM process abnormal diagnosis system. First, the data are stored in a circular array to speed up the processing time, and the coefficient of variation feature is added, which has effectively extracted the abnormal characteristics. In terms of diagnostic methods, the composite voting model established by neural networks, random forests, and XGB-RF (extreme gradient boosting applying RF) can provide robust diagnostic results. Finally, through the Node-RED webpage and MQTT agreement, it can provide the ability to monitor machine abnormalities in real time. Through refinement and optimization of the previous research results, this study took the electrical discharge machining diamond grinding wheel as an example, and developed a warning that can be issued within 3 min when abnormalities (abnormal patterns such as polycrystalline diamond high protrusions) occur, with an accuracy of 93% and a false positive rate. The abnormal diagnosis ability is less than 0.2%. Therefore, the online abnormality monitoring system developed by this research institute will be able to provide online abnormality diagnosis for electrical discharge machining.

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Active gap capacitance electrical discharge machining of polycrystalline diamond

Cited by 25 publications

References 28 publications

Electrical discharge machining of polycrystalline diamond: A review

Electrical discharge machining of polycrystalline diamond: A review

The state of the art of electrical discharge drilling: a review

Development of an On-Line Defect Detection System for EDM Process

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