EDM or Electrical Discharge Machine uses thermal erosion to remove small bits of conductive metal using repeated electrical discharges between the cutting tool, which functions as the electrode, and the piece itself in the presence of a dielectric fluid.
Here a high frequency electrical discharge occurs in the gap between the cutting tool and the piece, and the heat essentially vaporizes small amounts of the metal, which are washed away in a continuous stream of the dielectric fluid. The temperature during EDM processing can reach as high as 15,000 degrees Fahrenheit, and can change the metallurgy of materials. When metallurgical changes occur, the area is referred to as the “recast” layer. The recast layer can be easily removed with various methods.
Though all EDMs use an electrical current to cut material, there are several types of EDM that may be used in a specific instance to achieve required results.
Predominantly there are two methods Wire EDM as well as ram EDM, again there are more sub categories in RAM EDM.
WIRE EDM
Wire EDM shapes material using a very fine, electrically charged wire which gets consumed during the process. Used wire get automatically replaced so that fresh wire remains in use.
The wire never actually touches the work, but maintains a gap of at least .001 inches.
The wire and the piece are flushed with a continuous stream of dielectric fluid, although in some cases they are both completely submerged. With the work piece submerged, you can achieve faster cutting speeds.
SMALL HOLE EDM / EDM DRILL
EDM Drill or Small Hole EDM is used to cut small and deep hole in the work piece. Holes can drilled as small as 0.003 and deep as much as 300 mm or even more. cylindrical electrode attached to the positive pole of a pulsed power supply. The work is attached to the negative pole, and the gap between the two is flooded with dielectric fluid. As the electrical pulses remove material, the electrode moves deeper into the work using the path cleared during the EDM process.
RAM OR SINKER EDM
Ram or Sinker EDM uses electrodes in various shapes to create unique and complex cuts. In Sinker EDM as the name suggest both the electrode and the workpiece are submerged in the dielectric fluid during the process.
Since the shapes are usually complex, it may require multiple passes. The first passes remove large quantities of material and leave a rough finish while the last pass ensures a smoother surface and exact finish details.
EDM MACHINING USES
EDM is a perfect companion for making of tooling, dies or other similar items. EDM has capability to complex and odd shapes out of extremely hard materials. Earlier EDM machining was only used in machine tool application but with advancement in the machine it has been widely used for cutting extremely complex shapes for automotive and aircraft components.
BENEFITS OF EDM MACHINING
- Cutting of extremely hard conductive materials that can prove challenging on conventional machining methods.
- EDM machining provides very smooth finish, with no burrs or rough patches so EDM is an excellent choice when finish or appearance matter in the final product.
- Drastic reduction in production time and unit cost and also provides increased throughput from the machine
- The precision inherent in the EDM process allows complex designs to be machined cost-effectively
- EDMs come with inbuilt precision and accuracy which allows machining of complex designs in cost-effective manner
GET IN TOUCH WITH SPARKONIX
Sparkonix is a leading EDM machine provider in India as well as overseas, We deliver top-notch machine with the highest quality. With exports to more than 45 countries, we have extended our services to automotive, aerospace, machine tool, medical and many more.