| 摘要 |
PURPOSE:To make it possible to enhance the accuracy of machining and to establish the technology of machining for mass production, by aligning the projecting end face of an electrode with the surface of a bearing to be machined so that the position of electric discharge machining is rotated along the surface of the bearing to be machined to form a groove, and thereafter by separating the electrode. CONSTITUTION:A positioning and lowering means positions an electrode holder 4 to which an electrode is set, to a shaft 6 to be machined, and is lowered down to a predetermined level. Further, the electrical discharge gap is set to a predetermined value depending upon the depth of an air groove. With a predetermined gap being held between a shaft holder jig 5 and the inner peripheral surface of the electrode, the jig 5 is eccentrically rotated, and the value of current for electrical discharge is set in accordance with the surface rough ness of the air groove, and electric discharge machining is carried out. The electrode holder 4 having completed a swing-machining step is raised from the machined shaft, then is positioned to a predetermined position for the next shaft to be machined and lowered to it so that electrical discharge is carried out for the next shaft. Due to such electric discharge machining, an air groove may be machined at the final machining step, and therefore, the machining of an air groove in an air bearing having a high degree of accuracy may be made in a highly effective mass production base with no machining sagging.
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