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Electrochemical Grinding (ECG)
Published in Gary F. Benedict, Nontraditional Manufacturing Processes, 2017
Surface finishes average 0.2–0.8 μ (8–32 μin.), with plunge-grinding methods giving a 0.12–0.24 μ (5–10 μin.) finish, and surface grinding producing finishes of 0.24–0.37 μ (10–15 μin.) No matter how hard, tough, or brittle a material is, ECG produces surfaces free of any grinding scratches, burrs, or bums. This is illustrated in the example shown in Fig. 10.7. Electrochemical grinding will also produce a better surface finish than conventional grinding in non-homogeneous materials.
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.
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.