The precondition of EDM is tool electrode, workpiece and pulse power supply. When the pulse voltage is applied between the tool electrode and the workpiece, an electric field is formed between the two electrodes. When the tool electrode keeps approaching the workpiece, the electric field strength between the two increases gradually. In fact, due to the micro tool electrode and workpiece to see if the surface is actually concave uneven, when the distance between the electrode and the workpiece is very small, the electric field strength is not uniform, we usually put out electric field strength prominent point or tip nearest a judge for the largest. When the distance between the electrode and the workpiece is reduced to a certain extent, the electric field intensity between the tool electrode and workpiece to rise sharply, the insulating medium is usually a breakdown discharge channel formed in a narrow space between the electrode and the workpiece, the interelectrode resistance in 10 seconds from insulation down to number ohm below the current time a sharp rise, inter pulse voltage to maintain voltage spark. Molecules under electric field electronic high speed moving to anode and the impact of working fluid medium or neutral atoms, the ionization of the formation of negatively charged particles (mostly electrons) and positively charged particles (positive ions), resulting in charged particle like avalanche as constantly increased, the dielectric breakdown and the formation of a discharge channel. Because the channel space is very small, the current density is very high.
The discharge channel of injection molding is a plasma consisting of positively charged positive ions, negatively charged electrons, and neutral particles such as atoms or molecules. Therefore, the temperature inside the discharge channel is very high and the distribution is uneven, and the center temperature is higher than 10000 degrees from center to edge. There is only one discharge channel in one pulse discharge time.
More than just our common plastic mould on a micro pulse discharge process in detail, in the discharge process of EDM is called between tool electrode and workpiece processing is very complex, according to different product processing process and time length, is thousands of times to put electric discharge between the accumulation process of hundreds of millions of times.