| 摘要 |
The technical field of the invention generally concerns electroerosively drilling small diameter holes, e.g. holes 6.0 mm in diameter and smaller. Such a small hole drilling apparatus includes a worktable for receiving a workpiece, together with a chuck and an electrode guide which receives and retains an elongated and thin tubular electrode. The drilling apparatus also includes a fluid supply and pump which delivers a first flow of machining fluid to an inner bore of the tubular electrode at a pressure of at least 20 kg/cm2. The drilling apparatus also includes a power supply for applying a series of electrical machining pulses between the tubular electrode and the workpiece. As material is removed from the workpiece, an electrode feed mechanism included in the drilling apparatus advances the tubular electrode into the workpiece to maintain the spacing between the tubular electrode and the workpiece. The improved drilling apparatus includes a secondary machining fluid control and a flushing nozzle which directs a second flow of the machining fluid along the outer surface of the tubular electrode toward the machining gap. As the tubular electrode pierces through the workpiece, the second flow of machining fluid keeps the space between the electrode's outer surface and the workpiece including the machining gap filled with machining fluid.
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