Effects of tool intermittent vibration on helical internal hole processing in electrochemical machining

Abstract

Ribbed holes can serve to increase the efficiency of the heat exchangers and improve the performance of industrial equipment. Increasing demand for small ribbed holes is a key driver in manufacturing technology research. Electrochemical machining has been shown to be a promising method for this. In this paper, an intermittent low-frequency vibration tool is used to demonstrate significant improvement to the geometry of internal ribbed holes. The process stability, material removal rates, and uniformity of features along the flow direction are improved. Firstly, a 3D model of the flow field within the interelectrode gap was developed to calculate and governing flow regime in the interelectrode gap. The simulation demonstrated that the fluid velocity fluctuates periodically and this enhances electrolyte flushing in the interelectrode gap during the machining process. Then, experimental tests for the manufacture of spiral ribs on small holes (Ø1.5 mm and 20–40 mm depth) are also demonstrated with accompanying variation of the tool vibration amplitude and frequency, respectively. Results show that groove depth was most greatly influenced by the vibration amplitude and that better uniformity could be obtained at higher vibration frequencies. The groove depth increased by 15% over nonvibrating control tests with enhanced uniformity.