# Research on Multi-Physical Field Coupling Simulation of Local Electrochemical Machining
## 5 Conclusions  
In this paper, a simulation model of local electrochemical machining considering the gas-liquid two-phase flow field and temperature field was established. The influence of the gas-liquid two-phase flow field and temperature field on the conductivity distribution in the simulation process was studied, and the reason for simulation error with pure electric field and the influence of cathode end width \(L\) on machining accuracy was analyzed. According to simulation and experimental results, the following conclusions can be drawn:  
Figure 19: Modified convex of the GOM scan: (**a**) 3D view, (**b**) front view, and (**c**) lateral view.  
(1) For local electrochemical machining, the two-phase flow field and temperature field jointly affect the conductivity distribution in the machining area. Due to the obvious gas-liquid two-phase interface in the processing process, the two-phase flow field plays a major role in the conductivity distribution, and the temperature field plays a minor role, which only determines the maximum conductivity of the machining area.  
(2) There are significant errors between the pure electric field simulation results and the multi-physical coupling simulation results, mainly due to the difference in conductivity distribution. For the pure electric field simulation, in order to simplify the simulation process, the conductivity of the machining area is assumed to be constant, which does not meet the actual processing conditions.  
(3) The choice of the cathode end width L plays a key role in the final machining accuracy. With the increase in cathode end width \(L\), the raised joint mark will gradually decrease until it basically disappears. With the continuous increase in the width of the cathode end, the sunken joint mark will be produced.  
(4) The pure electric field simulation results have a significant error with the experimental results, and the maximum error is 0.28 mm and 0.32 mm, respectively. The multi-physical field coupling simulation results are basically consistent with the experimental results, the deviation is within 0.06 mm, and it is proved that the multi-physical coupling simulation can predict the local electrochemical machining results with high precision, which is of great significance to improve the precision of local electrochemical machining. When the cathode end width \(L\) = 3.7 mm, a casing convex meeting the target requirements is successfully machined. Its side taper changes from the initial \(-8^{\circ}\) and \(14.5^{\circ}\) to \(0.15^{\circ}\) and \(0.56^{\circ}\), respectively. The practical application value of local electrochemical machining is proved.  
Conceptualization, J.Y.; methodology, D.W.; COMSOL Multiphysics software, J.Y.; experiment, J.Y.; writing--original draft preparatio, J.Y.; writing--review and editing, D.W.; All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Natural Science Foundation of China (no. 52175414), National Natural Science Foundation of China for Creative Research Groups (51921003), Natural Science Foundation of Jiangsu Province of China (No. BK20220134) and China Postdoctoral Science Foundation (2019M661833).  
Not applicable.  
The authors declare that they have no conflict of interest.