What is the working principle of precision hole machining?

When the precision hole is used to process the circular hole, the cathode should be rotated at a certain speed to improve the shape accuracy of the hole. ECM can be used to process small and small holes with large aspect ratio, such as cooling holes of aeroengine blades, automotive filter nozzles, computer printed circuit boards, etc. Using micro-electrochemical machining (MEM) technology, GE Corporation of the United States earlier used shaped tube electrodes to process smooth cooling holes with diameter of 1mm and aspect ratio greater than 50 on turbine engine blades and combustor components. The production efficiency is high (compared with the electrical discharge machining), the surface roughness value is low, the Ra can reach 0.2~0.8 m. There is no residual stress and deformation on the machined surface. There is no burr and flash in the hole. The research direction of micro-electrochemical machining is to develop high-precision professional machine tools, tool cathode manufacturing, to limit stray corrosion, to improve machining accuracy, and to develop high-frequency narrow pulse width pulse power supply.

High speed drilling is adopted in precision hole machining, which can improve the shape, position accuracy and aperture accuracy of micro holes. High-speed drilling requires very high spindle system. At present, air turbine spindle and precision high-frequency motor spindle are mainly used. Vibration drilling can improve chip breaking and chip removal ability. Piezoelectric actuator or giant magnetostrictive actuator are installed on rotating spindle. Advanced micro-hole machining technology based on EDM (Electric Discharge Machining) is a special machining technology which is based on the electrocorrosion phenomenon of pulse discharge between positive and negative electrodes. It can focus the ion beam and make it deflect and scan, so the focused ion beam can process circular holes and special-shaped holes, not only through holes, but also blind holes, and the processing depth of blind holes can be easily controlled to high precision. Ion beam processing in vacuum, the processing surface will not be oxidized, especially suitable for processing oxidizable materials and semiconductor materials with high purity requirements.

The working principle of the orientation function of precision hole machining is that the spindle moves to a set height directly above the machining position of the part, then moves a certain distance along the horizontal direction, the spindle rotation stops, the knife point rotates according to the set angle, that is, the knife point and the part form a fixed angle, the spindle moves along the axis direction to reach the set position. The spindle deviates a certain distance along the horizontal direction, the center of the spindle coincides with the center of the hole, the spindle rotates and opens, and the cutter is bored backwards from the bottom to the top. After finishing the machining, the spindle stops rotating, the tip of the cutter deviates from the center of the hole and the cutter withdraws from the part. The structure is special and the space size is limited. The size of the parts can not be guaranteed by the usual machining method.