Development and application of a micro-honing-tool

The major aim of this study is to present a novel technique for honing the micro-hole. It is difficult that regarding the finish machining of the micro-hole that the diameter is less than 300 μm. First, a new process that to on-line accurately fabricate the micro-honing-tool using micro-EDM, micro-co-deposition and micro-wire-EDM is proposed for honing the micro-hole. A micro rod for as the substrate of the micro-tool is formed by wire-EDM and then co-deposited with 0-2 μm CBN-abrasives. Subsequently, it is axially and crisscross cut for an appropriate length by micro-wire-EDM to make the crotched microstructure. The whole processes are able to be on-line realized since all working positions are recorded in detail and fabrication technologies are offered sufficiently on the same system. As a result, per the same fabrication-system, the micro-honing process is also on-line conducted. The finished micro-honing-tool is employed directly without unloaded and reloaded. The grinding-block can compactly stick on the wall surface of the micro-hole due to the radial elasticity of the micro-tool and then fast grind away the uneven surface by removal of micro amount. Experimental results demonstrated that the circularity and surface roughness on the hole-wall is evidently improved. Comparing with the obtained machining surface by micro-EDM hole-drilling, the original surface roughness of near one-sixth time can be achieved. It is indicated that the micro-hole can be honed accurately using the proposed technique.