Thermophysical Properties of an EDM Graphite Electrode
Graphite is one of the most commonly used materials in the EDM industry. Its many advantages make it an ideal choice for a wide range of applications from mold manufacturing to parts processing.
Compared to copper electrodes, graphite material offers several cost savings and quality improvements. This includes less machining time and a lower cost of production for the electrodes, as well as faster EDM times and improved throughput from the machine.
Thermophysical Properties of Graphite Electrodes
An edm graphite electrode's thermophysical properties determine how it processes the energy generated from cutting and removing metal. When current is sent through the graphite electrode, it causes a spark, which erodes a small amount of material in the workpiece at a time. This process creates a desired shape in the workpiece through constant sparking and erosion.
Thermophysical Properties also determine how the graphite electrode responds to heat during discharge. Graphite electrodes have an excellent heat resistance, which makes them more resistant to wear than copper or other metal-based materials.
Graphite electrodes are available with fine and coarse particles/pore size, which are important for the type of surface finish that is achieved in the cavity. Grades with larger particles and pores will not produce as fine a finish as grades with small particle/pore size, and may lead to increased electrode wear, which can cause an unstable EDM process.
In addition, the flexural strength of the graphite grade must be sufficient to resist the deflecting force of flushing pressure or orbiting during the EDM process. Ideally, graphite with a flexural strength of more than 700 kgf/cm2 is best for thin ribs.
