Gas–liquid two-phase flow field analysis of two processing teeth spiral incremental cathode for the deep special-shaped hole in ECM.

This paper adopts electrochemical machining (ECM) to machine spiral-shaped deep holes, which are difficult to machine by conventional machining methods. Firstly, a cathode structure with two working teeth with increasing spiral end face dimensions was designed. The interstitial flow field and interstitial bubble field were modelled, and simulations were carried out using COMSOL simulation software to realise the optimisation of the cathode working teeth structure. The results show that the cathode structure with four incremental baths provides good uniformity of gap electrolyte flow, and the flow rate is significantly increased, reaching over 6 m/s. The concentration of bubbles in the interstitial electrolyte is significantly reduced, with a reduced rate of 47% and a smaller bubble distribution area. Processing accuracy and surface quality are effectively improved. Secondly, ECM experiments were carried out. The experimental results were analysed using the response surface method for multi-objective optimisation. The optimised process parameters were obtained as follows: inlet pressure 0.7 MPa, machining voltage 10 V and feed rate 0.9 mm/min. Finally, a qualified sample was machined using the optimised process parameters. The dimensional deviation is 0.28 mm and the roughness is 1.398 μm, which meets the product requirements. This simulation and optimisation method effectively shortens the cathode development cycle and reduces production costs. [ABSTRACT FROM AUTHOR]