Analysis and test of conductive shaft of large horizontal NC ECM machine tool

Abstract

In order to solve the problems of serious heating and easy ablation of conductive shaft in electrochemical machining of special-shaped deep hole with large aspect ratio, the two schemes of single-sided copper bar and symmetrical copper bar of conductive shaft are studied by ANSYS software. By establishing the thermoelectric coupling model of the conductive shaft, the distribution law of temperature field and thermal deformation of conductive shaft under different working conditions is analyzed. The conductive shaft structure based on symmetrical copper bar scheme is determined. Monitoring points are set at the key parts of the conductive shaft, and the temperature field distribution is verified by using the data acquisition card. The temperature acquisition results are consistent with the simulation results. Through the machining test of special-shaped inner spiral deep hole parts with large aspect ratio, the results show that under the conditions of working current of 15 000 A, feed rate of 5 mm/min, and continuous machining for 14 h, the forming accuracy of the workpiece is ± 0.15 mm and the surface roughness is better than Ra0.8 μm. The performance of the conductive shaft is stable and meets the actual processing requirements. The heat dissipation performance of the conductive shaft is optimized by providing air flow on the upper surface and side at the same time.