Research On Electrochemical Micro-hole Drilling Process

The application of Micro-holes is abroad in industry. For example there are many cooling holes in jet turbine blades in aerospace ,and many nozzles are used. Many methods to machine micro-holes,such as machine drilling,Electro-discharge machining, Focused ion beam machining and Laser beam machining ,are employed.The aiguille's stiffness is small in boring holes in machining hard materials. Electro-discharge machining,Laser beam machining and Focused ion beam machining may leave heat affected layer. Electrochemical machining (ECM) is competent for micro holes without heat affected layer.ECM is an anodic dissolution process of the workpiece in a flowing electrolyte where the shape of the tool as cathode is copied into the workpiece as anode with the removal of the anode ion by ion. Due to the tiny size of metal ion, this micro-dissolution process brings ECM tremendous potential in the micro-machining field. The following work has been done in this paper:1) The basic theory of pulse ECM and the methods of ECM micro holes are proposed.2) The cathode are machined in alkaline electrolyte and it is insulated with the capillary tube.3) The experiments on the process of machining micro holes with the cathode without the insulated layer in the thickness of 0.12mm stainless steel piece with pulse power are carried out in acid electrolyte. The effect of both electric pulse parameter and the velocity of the cathode on the lateral clearance in the entrance of the hole is discussed.4) The experiments on the process of machining micro holes with the cathode with the insulaed layer in the thickness of 1mm stainless steel piece with pulse power are carried out in acid electrolyte. The effect of both electric pulse parameter and the velocity of the cathode on the lateral clearance in the entrance of the hole is discussed.