Research Of Composite Processing Technology On Metal Holes Without Recast Layer

The technology of processing micro holes are used widely in many industries such as aerospace, national defense, machinery, instrument and electronic industry. Most simple processing method about the micro holes have their disadvantages at present.This paper put forward a processing method combining the electrical discharge machining(EDM) and the electrochemical machining(ECM) to machine micro holes. It includes the advantage of the two kinds of processing method above, and can effectively improve the surface quality of the micro holes and remove the recast layer on the surface of the micro holes. We mainly finish the work as follows:Finish the simulation about the pressure of working water in the electrical discharge machining machine and the location of the appliance fixing the electrode. The pressure of working water and the location of the appliance fixing the electrode are adjusted based on the result of the simulation;Have done the electrical discharge machining experiment and pick out the best processing parameter. The law the processing parameter impact on the diameter of the micro holes and the width of the recast layer under different diameter of the electrode are analyzed and the best processing parameter under each diameter of the electrode is selected:under the 0.5mm diameter of the electrode, when the peak current is 2A and the pulse width is 150μs, the experimental result is that the diameter of the micro hole is 0.653mm and the average width of the recast layer is 42.7μm; under the 1.0mm diameter of the electrode, when the peak current is 4A and the pulse width is 70μs, the experimental result is that the diameter of the micro hole is 1.200mm and the average width of the recast layer is 19.7μm;Combining the best processing parameter in the electrical discharge machining experiment, the electrochemical machining experiment is completed. Different processing parameter is chosen to get on the electrochemical machining, the situation about the expansion of the micro holes’ diameter and the removal of the recast layer are researched.It is showed in the research that electrochemical machining has a significant effect on the removal of the recast layer. For instance, under the 1.0mm diameter of the electrode, when the peak current is 4A and the pulse width is 70μs in the electrical discharge machining and the supply voltage is 5V and the processing time is 3 minute, the surface of the micro hole is smooth and the recast layer is removed completely.