Fabrication of helical micro pins by electrochemical machining

Helical tools have been proven to enhance the circulation of electrolyte between electrodes in electrochemical micro-drilling. However, the fabrication of micro helical tools is difficult by traditional machining methods. The aim of the present article is to fabricate a helical tungsten micro pin by electrochemical machining. Experimental results show that a helical pin can only be fabricated in the limiting current conditions, and the length of threaded region is proportional to the anode rotating rate. Under the conditions of applied voltage equal to 2.6 V, machining time of two minutes, and the anode rotating rate of 4,000 rpm, an optimal micro helical electrode with thread depth around 17 micro-metre can be obtained. The mechanism for the formation of helical groove is well explained.