Three types of electrical discharge machine: die sinking edm, wire cut edm, drill edm

Types of electrical discharge machining: die sinking edm, wire cut edm, drill edm

The working principle of EDM is to rely on electric corrosion to erode excess metal during discharge between the machine tool and the workpiece (positive and negative electrodes), so as to achieve the processing method of the size, shape and appearance quality of the workpiece.

Machining electrodes: Generally, electro-corrosion-resistant materials with good conductivity, high melting point and easy processing are required, such as copper, graphite, copper-tungsten alloy and molybdenum. During processing, the tool electrode and the product are lost at the same time, but it is less than the amount of removal of the workpiece metal, and it can be ignored when it is close to 0.
Coolant: As a discharge medium, it plays the role of cooling and chip removal during processing. The requirement for coolant is a medium with low viscosity, high flash point and stable, such as kerosene, deionized water and emulsion, etc.
After the pulse voltage is applied between the two electrodes, when there is an appropriate gap between the workpiece and the electrode, the current will break down the coolant medium between the workpiece and the tool electrode, and a connected discharge channel will appear.

The discharge channel generates high temperature instantaneously, which melts and even vaporizes the surface of the workpiece, and also vaporizes the coolant medium, which rapidly shrinks at the discharge gap and explodes. etch pits.

After the pulse discharge is completed, return to a safe distance to restore the insulation of the coolant. In this way, the pulse voltage acts on the workpiece and the tool electrode repeatedly, the above-mentioned reaction process continues, and the surface of the workpiece is gradually etched away.

The servo machine continuously adjusts the absolute distance between the tool electrode and the workpiece, and automatically feeds it to ensure the normal operation of the pulse discharge until the parts of the required size are processed.

1. CNC die sinking edm process
The tool electrode is usually a copper or graphite shaped electrode, which can be of all shapes that can be manufactured, and the processed shape is the corresponding cavity.

2. Wire cut machine process
Electrical discharge machine wire cut edm processing is divided into brass wire and molybdenum wire. The wire diameter uses electrode wire with a diameter of 0.1mm~0.3mm to process the straight-grained surface parts, which can be punch parts or die holes.

3. Drill edm process

A thin tube (>Φ0.3mm) electrode is used, and the high pressure water-based working fluid is flushed into the tube; the thin tube electrode rotates; the perforation speed is very high (30～60mm/min); starting hole of wire cutting edm; large depth-diameter ratio Small holes, such as nozzles, etc.;