Micro Grinding Blind Holes in Hard Tungsten Carbide with Polycrystalline Diamond Micro Tools

摘要

This paper describes a micro hole drilling technique using micro electro-discharge machining (μEDM) and poly-crystalline diamond (PCD) micro tools to improve the precision of holes drilled in hard tungsten carbide. A two-step technique is described for achieving faster, more precise and accurate holes. First, the hole is drilled with μEDM using tungsten electrodes shaped by WEDG. Next, the holes are improved by grinding with PCD micro tools, which are also shaped by WEDG. It is found that holes fabricated with PCD micro tools are superior since they have less heat-affected zone, exhibit improved surface finish, and have less form error. Also, the hole size is more accurately controlled with PCD tools, since no gap exists between the tool and workpiece and because tool wear is less than electrode wear during μEDM.