Research On Flared Micro-hole Array Processing By Electrochemical Machining

The sieve-sheets with flared section micro-holes have many excellent featuresincluding: can significantly reduce the filter (screen) blockage degree and chance,improve the filtering and screening efficiency, prolong operating life and duty period,which make it will be the new development of the high-performance fine filter (screen)mesh. Template electrochemical machining which bases on the principle of materialsetched selectivity on the specific design has many especial process advantages in themanufacture of micro-hole array. With the aid of template electrochemical machiningprinciple, one new technology, namely tapered holes double-sided templateelectrochemical machining, was put forward in this paper through optimizing thetemplate micro-holes open angle and assembling auxiliary anodes. This paper wassupported by Scientific and Technological Project of Henan Province(9210221035) andMiddle-aged Excellent Teachers Support Project of Henan Province Colleges andUniversities(2009GGJS-034), and relying on the technology platform of tapered holesdouble-sided template electrochemical machining and targeting at realizing flaredmicro-hole array, the influences of process parameters on the workpiece surface currentdensity distribution law were analyzed, and the flared micro-hole array was obtained.The specific research content as follows:(1) The influences of template opening angle (acute, right, obtuse) and shieldedanode on the workpiece surface current density distribution law were analyzed. Theresults showed that: the surface current density distribution curve using singly an acuteopening angle template was approximate trumpet, however, which were similar to twoparallel lines when used singly the obtuse opening template or the auxiliary anode,especially, when the auxiliary anode and obtuse opening template were placed on theworkpiece in turn, the workpiece surface current density distribution curve was almosttwo parallel lines.(2) Based on the simulation result, the tapered holes double-sided templateelectrochemical machining was put forward. In the process, auxiliary anode and obtuseopening template were stacked in one surface of the workpiece in turn to achievestraight wall end of the flared hole, and the acute angle opening template was closed to the other surface of the workpiece to get flared end. The influences of current density,machining gap, electrolyte concentration, template thickness, templates opening andother parameters on the workpiece surface current density distribution law weresimulated. The results showed that: The diameter and opening of micro-holes withflared cross-section both increased with the current density and electrolyteconcentration increasing, but decreased with the increase of machining gap andtemplate thickness, additionally, reduced firstly and increased afterward with theincrease of opening angle of acute template; with the increase of opening angle ofobtuse template, the change of diameter and opening of micro-holes with flaredcross-section were not obvious, but the proportion of micro-holes straight walldecreased.(3) On the basis of the characteristics of tapered holes double-sided templateelectrochemical machining technology, the experimental system was developed, and theinfluences of current density, machining gap, electrolyte concentration, templatethickness, templates opening and other parameters on the workpiece surface currentdensity distribution law were experimented relying on the electrolysis device, and thecorrectness of simulation results as well as the technical feasibility of tapered holesdouble-sided template electrochemical machining were confirmed. Finally, two types ofmicro-hole array with significant flared section feature including high flaring degreeand high intensity were manufactured using the optimal process parameters.