Investigation of flow fields during the electrochemical machining of variable-section pit arrays

Variable-section pit arrays play an important role on the linear cutter staplers, which are used for surgical suturing. Although numerous methods can be employed to generate pits on the surface of a workpiece, it remains a challenge to form variable-section pit arrays on the surfaces of thin-walled workpieces with high precision and efficiency. Thus, this paper proposes a method for the electrochemical machining of variable-section pit arrays using a radial internal fluid supply. By using simulations and experiments to investigate the flow fields of the electrolyte, it was found that electrolyte supplied by internal electrodes enhanced the accuracy and consistency of the pit profiles. The influence of the electrolyte pressure, pulse current, and feeding speed on the pit profiles of machined variable-section pit arrays was analyzed. To fabricate the designed pit (length = 1750 +/- 20 mu m, width = 1000 +/- 20 mu m, and depth = 400 +/- 10 mu m), the machining parameters were optimized. Using these optimized parameters (electrolyte pressure = 0.5 MPa, pulse current = 35 A, feeding speed = 0.42 mm min(-1)), ten rows of variable-section pit arrays were generated on a 17-4PH stainless steel plate with a thickness of 1 mm. The resulting length, width, and depth (mean +/- SD) were 1750.56 +/- 0.55 mu m, 999.62 +/- 0.63 mu m, and 396.71 +/- 0.53 mu m, respectively, demonstrating the high precision and efficiency of the proposed method.