Principle of Micro hole EDM Machine Tool and Discharge Difference

The principle of micro EDM is not fundamentally different from that of ordinary EDM. The quality of the machined surface mainly depends on the size and depth of the etch pits, that is, the energy of a single discharge pulse; The machining accuracy is closely related to such factors as discharge gap, process system stability and electrode loss. Micro EDM also uses pulse power supply to transfer high-frequency discharge energy to the discharge gap, and realizes material removal by generating high temperature thermal effect and other comprehensive effects, so as to achieve the purpose of workpiece processing.

1. The electrode of fine EDM with very small discharge area is generally<5~100 μ M, for one<5 μ M electrode, the discharge area is less than 20 μ M2, when discharging on such a small area, the distribution range of discharge points is very limited, which is easy to cause the concentration of discharge position and time, increase the instability of the discharge process, and make micro EDM difficult.

2. Single pulse discharge energy is very small

In order to adapt to the requirements of electric spark discharge with very small discharge area and ensure the dimensional accuracy and surface quality of machining, the removal amount of each pulse shall be controlled within 0.10-0.01 μ Therefore, the energy of each discharge pulse must be controlled between 10 – 6 and 10 – 7 J, or even less.

3. The discharge gap is very small

Because EDM is non-contact machining, there is a certain machining gap between the tool and the workpiece. The size of the discharge gap varies with the processing conditions, ranging from several microns to hundreds of microns. The control and variation of discharge gap directly affect the machining quality, stability and efficiency. Especially in micro EDM, the machining of micro holes accounts for the majority, and the size and stability of discharge gap are the key to the success of micro hole machining.