Discussion on the rationalization of ink polarity electric activation technology and electric spark lathe

The spindle lifting knife can improve the chip removal during the deep processing of the deep groove (cavity) narrow slit micromachining, and prevent the phenomenon of carbon deposition and secondary discharge (referring to the non-recurrence of the surface on the processed surface due to the intervention of the electric corrosion product, etc.) The necessary discharge, which is the inclination of the machining depth direction and the blunt edge of the machining edge, etc.). The machine tool 3 increases the spindle movement speed, and the maximum lifting speed is 15 m/min, which can eliminate the concentrated discharge which occurs due to the elimination of the electrolytic corrosion product, and the secondary discharge gap unevenness is greatly suppressed. When the peak current of the machine tool 1 is 30A, the pulse width is 100μs, the pulse interval is 120μs, and the electrode type is ISO-63, the workpiece is charred and the electrode is ablated, as shown in 5. This is mainly because the current is too large, the electrolytic etching product has too much processing debris, and it is too late to discharge, forming carbon deposits on the surface of the workpiece, and the edge of the electrode generates granular protrusions, causing a short circuit, causing arc discharge, causing the graphite electrode to burn. eclipse.

Pulse power supply and intelligent control of the pulse power supply for EDM processing is to convert the power frequency AC current into a unidirectional pulse current of a certain frequency to supply the energy required for the spark discharge gap to etch the metal. Pulsed power supplies have a large impact on the productivity, surface quality, processing speed, and electrode loss of EDM. The pulse power supply of the machine tool 3 is an adaptively controlled pulse power source. When the workpiece and the electrode material, the contamination degree of the working fluid, the chip removal condition, the processing depth and the processing area change, the pulse parameter can be automatically adjusted to prevent arc discharge. And achieve the highest production efficiency. Moreover, it has a miniature pulse power supply that can output tiny pulse energy for micromachining. Therefore, the processing speed of the machine tool 3 is relatively fast and the discharge is stable.

The working fluid working fluid, like the pulsed power supply and control system, directly affects process factors such as processing efficiency, surface quality, and electrode loss. The function of the working fluid is to form an electric spark breakdown discharge channel, and to quickly restore the insulation state of the gap after the end of the discharge, to compress the discharge channel; to help throw and remove the electric corrosion; to cool the electrode and the workpiece.

The working fluid generally has the following conditions: low viscosity, good insulation, safe operation, strong cooling capacity, non-corrosive work, and stable discharge processing characteristics for a long time. At present, the commonly used working fluids mainly include kerosene, synthetic electric spark working fluid and mixed powder working fluid. According to the actual production experience, when using graphite electrode EDM, kerosene, special synthetic spark oil and mixed powder working fluid are generally used. The machine tool 1 and the machine tool 2 use kerosene, the discharge is unstable, the gap is large, the surface quality of the processing is poor, and arc discharge is liable to occur. The machine tool 3 uses a special EDM fluid, which has a high surface quality and a fast processing speed. The machine tool 4 uses kerosene, but it has a mixing function to achieve a high surface quality.

Conclusion (1) It can be seen from the comparison of four kinds of machine tools that the machine tool 3 has a faster processing speed and a higher surface quality, but the electrode loss is larger, which is suitable for precision machining; the machine tool 4 has a good surface quality and a small electrode loss, but The processing speed is too slow and the efficiency is low. The discharge state of machine tool 1 and machine tool 2 is unstable, arc discharge and ablation are easy to occur, and the surface quality is low, which is not suitable for EDM machining of graphite electrodes.

(2) EDM machine has great influence on the electromachining characteristics of graphite electrode. Spindle performance affects the stability of EDM, prevents secondary discharge and improves the surface quality of processing. Pulse power supply can improve processing speed and prevent arc discharge; working fluid is improved. Surface quality and processing speed.

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