Experimental Study Of Machining Array Micro-pits In Electrochemical Machining Method With A Mask Onto The Anode

The functional micro-dimples texturing on the parts’surface which can store the lubricating oil between function pairs has great application prospects with its functions on antiwear, reduction of resistance and improvement of part life. Among the machining of micro-dimples texturing, through mask electrochemical micromachining (TMEMM) has its great advantages, such as its applicability regardless of material’s mechanical properties, the absence of tool wear, internal stresses, deformation, splash and burr after machining. Besides, it also has high opening ratio.The paper studied the crafts about through mask electrochemical micromachining. Photopolymer resist film was used to replace the traditional photo resist, and experiments were conducted to determine the optimal parameters about the preparation of HT200film; After the comparison between side punching system and positive punching system, it was proved that positive punching system can get more uniform flow field and optimal bonding effect between the film and part; Finite element analysis model to circular pits was presented and calculated to explain the phenomenon about "isolated island" during processing. Experiments were operated to analysis the current density and processing time’s effect on the3D profile and size uniformity of circular pits, and the change law of the interelectrode voltage during machining was also concluded. The optimal parameters were concluded as follows:250μm for film’s diameter,8A/cm2for current density and50s for processing time. The15×15array micro-pits with diameter of0319.3μm, depth of75.2μm and23.3μm for diameter standard deviation can be acquired with the concluded parameters.The problem about the removal of fillet was existed when applying TMEMM to the machining of square-shaped pits. The application of compensative structure on the mask and pulse power supply can reduce the radius of fillet and improve the forming accuracy. Three kinds of compensative structure were designed, and when chose current density as4A/cm2with the optimal film structure can get the square-shaped pits with56.34μm for the radius. Pulse power supply can get better forming accuracy than DC power supply. The experiments with the condition of7V for the voltage,50kHz for the pulse frequency,30%for the duty ratio,10%for the electrolyte concentration, can get the square-shaped pits whose side length is449.7μm, fillet radius is38.10μm, and the height is58.96μm.TMEMM was applied to the machining of characters and square-shaped boss. The results revealed that with the condition of8V for the voltage,40kHz for the pulse frequency,10%for the duty ratio,10%for the electrolyte concentration,5min for the machining time and with the optimal mode of compensation, the square-shaped dimples can formed, whose side length is973.63μm, fillet radius is47.2μm, and the height is38.59um. The results also showed that the characteristics of the font are obvious, the stroke is clear; the minimum size of the contour can approach1.33mm×1.17mm。...