OPTICAL ALIGNING DEVICE FOR POSITIONING THE ELECTRODE OF A SPARK DISCHARGE MACHINING APPARATUS

摘要

Disclosed is a spark discharge machining apparatus including a machining electrode, a worktable for supporting a work-piece to be machined and optical means for accurately establishing the location of the electrode relative to the worktable. The worktable is translatable for measured distances into mutually perpendicular directions such that a work-piece positioned thereon can be selectively aligned relative to the electrode. The optical device is positionable at a precisely determinable location on the worktable and includes a tool microscope and one or more prisms for reflecting an image of a reference point on the bottom surface of the electrode into the field of view of the microscope. By moving the worktable such that a reflected image of a reference point on the electrode is brought into coincidence with a reference point in the optical device, the location of the electrode relative to the worktable is precisely determined.