Xiaolong Fang

Analysis and Reduction of Stray-Current Attack in Reciprocated Traveling Wire Electrochemical Machining:

Traveling wire electrochemical machining is a promising approach for the fabrication of various metal parts. However, the stray-current attack deteriorates the surface quality while it is employed to cut thick workpiece as a normal pulse or DC is used. In this paper, the characteristics of the stray-current attack in reciprocated traveling wire electrochemical machining are firstly identified, and special insulating methods are proposed to reduce the effect of the stray-current. The model of electric field is built. Both the simulation and the experimental results illustrate that the stray-current attack can be reduced significantly by the proposed insulating methods. Finally, structures with fine surface quality on stainless steel 304 with thickness of 20 mm were successfully produced.

Electrochemical Drilling of Deep Small Holes in Titanium Alloys with Pulsating Electrolyte Flow

Inherent characteristics of electrochemical drilling (ECD) mean that it is a major solution to the machining of deep small holes in difficult-to-cut materials. The removal of insoluble by-products from the machining gap determines the accuracy of control and limits process capacity. Pulsating electrolyte flow is introduced to enhance the removal rate of insoluble products by reducing the hold-down pressure caused by the electrolyte. Experiments are conducted to optimize a stimulus signal for the pulsation and to investigate the electrolyte pulsation frequency, pulsation amplitude, applied voltage, and electrode feed rate in the machining of deep small holes. The results indicate that optimized pulsating flow is effective in accelerating by-product removal and enhancing machining accuracy and maximum machining depth. With the optimized parameters of 5 Hz in frequency, 0.2 MPa in amplitude, and 0.5 MPa in average pressure, a deep hole was machined in titanium alloys of 20 mm depth and 1.97 mm averaged diameter.