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Electrochemical Machining
Published in Madhav Datta, Electrodissolution Processes, 2020
Electrochemical grinding (ECG) utilizes both mechanical and electrochemical actions to remove materials. For electrochemical action, an electrolyte solution is pumped into the workpiece which acts as an anode. The ECG process uses a conducting grinding wheel in which an insulating abrasive, such as diamond particles, is embedded as shown in Figure 8.12. The rotating grinding wheel works as a cathode tool. The abrasive particles of the grinding wheel contact the workpiece and the gap between the wheel and workpiece makes a passage for electrolyte circulation. The gap voltages range from 2.5 to 14 V [52]. The material removal is achieved by the action of the electrochemical process which leads to the formation of an anodic layer on the workpiece surface. The abrasive grains help in the removal of the surface layer. The dissolution process stabilizes by the continuous supply of the fresh electrolyte and exposing of the fresh workpiece surface. The wheel rotation is an important parameter that governs the accuracy and surface quality in ECG. The use of pulsating current/voltage in ECG offers better control of the machining process. By using pulsed power, the balance between electrochemical and mechanical removal can be adjusted by setting optimum pulse on-time and duty cycle. The contribution of the electrochemical versus the mechanical portion of the metal removal rate (MRR) in ECG depends on the current applied current density. With the application of high currents, the mechanical portion of the metal removal rate decreases [53]. At high current densities, the metal removal rate due to electrochemical dissolution increases, which results in an increased interelectrode gap. Hence, there is a reduction in mechanical force on the workpiece exerted by the ECG wheel. In addition, the bubble volume fraction also increases due to an increase in current density. This contributes to a decrease in MRR caused by erosion.
Electrochemical Grinding (ECG)
Published in Gary F. Benedict, Nontraditional Manufacturing Processes, 2017
Electrochemical grinding (ECG) is a process that combines both electrochemical and mechanical action to remove hard or fragile electrically conductive materials. Because of the electrochemical nature of the process, the workpiece material is “ground” without producing burrs and without generating heat, distortion, or stress.
Combined rough and finish machining of Ti–6Al–4V alloy by electrochemical mill-grinding
Published in Machining Science and Technology, 2020
Shen Niu, Ningsong Qu, Xiaokang Yue, Gangqiang Liu, Hansong Li
Electrochemical grinding (ECG) is a hybrid machining process based on a combined system of electrochemical machining (ECM) and mechanical grinding (MG) (Mohammad and Wang, 2016). In ECG, most of material is removed from the workpiece through electrochemical dissolution (≈90–95%), and the rest is removed with grinding (≈5–10%) (Puri and Banerjee, 2013). Compared with MG, ECG has a high material-removal efficiency, long tool life, and better surface properties and machining accuracy, particularly when working with difficult-to-cut alloys (Zaborski et al., 2004; Hascalik and Caydas, 2007). In addition, the major problem of applying ECM to titanium alloys is the formation of a dense oxide layer on the workpiece surface, which can hamper the current flow and affect the stability of the dissolution process (Chen et al., 2017; Deshmukh et al., 2017). ECG has the advantage of using mechanical grinding to continuously remove any oxide layers, so there is less need to apply harmful or harsh electrolytes (Kozak and Oczoś, 2001; Curtis et al., 2009). Thus, ECG is a candidate for hybrid manufacturing that includes the machining of titanium alloys.
Evaluating electrochemical micromachining capabilities for industrial applications: A review
Published in Materials and Manufacturing Processes, 2023
Jitendra Singh, Rishi Kant, Anutosh Nimesh, Nitish Katiyar, Shantanu Bhattacharya
The combined action of electrochemical process and abrasive energy in the electrochemical grinding machining process subtracts the material from the substrate surface.[171–173] Electrolyte grinding is a hybrid method that combines electrochemical machining and the traditional grinding process. An illustrative diagram of electrochemical grinding (ECG) is depicted in Fig. 27. A rotating grinding wheel serves as a cathodic tool in this hybrid process.[43] The workpiece comes into contact with the grinding wheel’s abrasive particles, and the flow of electrolyte between the gap present in the wheel and the substrate surface. The gap voltages vary from 2.5 to 14 V.[171–173] The electrochemical procedure removes the material at the start of the machining process, followed by the formation of a passivating film on the surface of substrate. Cutting action by the abrasive grains removes the passivating layer and stabilizes further dissolution by exposing the new substrate surface.[171] Electrochemical dissolution accounts for most of the material removal in micromachining, employing a combination of abrasive and electrochemical action. Pulse electrochemical grinding (CECG) has been found to have improved control of the drilling process as compared to the typical approach, which uses a direct current power supply. By adjusting the optimal pulse-on time and duty cycle with pulse power, the stability between mechanical and electrochemical elimination may be achieved. In electrochemical grinding-based micromachining of µ-holes, tool rotation is a key parameter that influences accuracy and surface quality.[171] In electrochemical grinding, very high and very low RPMs are not suitable because at low RPM, electrolytes do not flow properly at the machining zone, while at high RPM, centrifugal forces are increased.