| 摘要 |
A cutting tool, preferably in the form of a scalpel, microtome or razor blade is fabricated from single crystal material such as aluminum oxide with a preferential etching process to produce a radius of curvature less than 100 Angstroms on the edge. Depending upon the etchant, the crystallographic orientation of the blank and the resulting different etch rates on blade surfaces, the preferential etching process not only sharpens a preformed edge but also, in one embodiment, produces an opposing edge which meets the sharpened edge at a point, thereby to produce a particularly efficient scalpel blade configuration having two cutting edges converging at a point for plunging and cutting. With respect to the sharpening of the cutting edge, consistent with all other blade forming requirements, the subject blade is made to a maximum sharpness by utilizing a maximum ratio of bevel plane etch rate to edge plane etch rate. This maximum ratio maximizes the edge sharpness when a steady state etching geometry has been achieved. In one embodiment, and for a given edge sharpness, blade drag is minimized by selecting the crystallographic orientation and etchant such that the etchant chemically polishes the bevels and maintains the planarity of the bevel planes. In order to achieve identical etching of the bevels meeting at the blade edge and thus maintain original blade geometry, the blank can be oriented such that the edge forming planes are crystallographically identical planes.
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