Abstract
Honing has been widely applied to engine cylinders and hydraulic cylinders, since not only surface roughness but also the roundness and straightness of the hole can be improved by the process. However, in the case of a surface roughness less than 1μmRz, burrs formed by the abrasives used significantly affect the surface roughness and make it difficult to attain smoother surfaces. In our previous paper, the electrochemical internal-surface finishing of a small hole using a honing machine and a soluble fluid after honing was proposed for accurate and efficient finishing. Experimental results clarified that passive-film generation on the machined surface could be prevented by mixing an inverse electrolytic current with the normal one, and that the surface roughness could be reduced because only convex parts on the machined surface were selectively removed, even when the soluble fluid used in honing is an electrolyte. In this study, honing sticks were used to remove the passive-film during electrochemical finishing after honing. Also, optimum machining conditions were discussed to attain higher-efficiency surface finishing. As a result, the internal surface roughness was decreased to less than 0.5μmRz in only 10sec.
