Electrical discharge machining is an excellent complement to conventional machining techniques for parts with specific geometrical requirements, such as CNC machining. The process is also attractive when used with Inconel because it can machine hard materials.
FREMONT, CA: Electrical discharge machining (EDM) is a non-traditional form of precision machining that removes material from a workpiece using thermal energy rather than mechanical force. It is sometimes known as Spark Machining because it employs electrical sparks with temperatures between 8000°C and 12000°C. When CNC milling and turning cannot produce the desired cut, such as sharp internal corners or a particularly deep cavity, engineers frequently turn to EDM.
PERKS OF EDM
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Greater design freedom
One of the primary benefits of electrical discharge machining is cutting shapes and depths that would be impossible with conventional machining techniques. These include undercuts and internal corners that are perfectly square. The absence of burrs due to the machining process is an additional advantage.
Non-distortion machining
In contrast to conventional machining methods, the tool never directly interacts with the workpiece during this procedure. There is no deformation if no forces are acting on the part. This enables the machining of highly delicate features without the risk of breaking. In addition, the absence of distortion allows for extremely tight tolerances of +/- 0.012mm.
Superior surface finish
Conventional material removal techniques, such as CNC milling, leave machining marks on the workpiece that must be removed by post-machining. EDM has zero-directionality to the surface finish, producing uniformly smooth surfaces without additional treatment. However, rapid EDM processing can leave a slight texture resembling bead blasting.
Precision
Despite its limited mass production capacity, EDM's high precision makes it ideal for manufacturing small parts and prototypes. The automotive industry frequently uses this method when manufacturing intricate engine components.
Unaffected by material density
A key characteristic of electric discharge machining is that it can machine through any conductive material. This allows for rigid machining materials such as Inconel and Tungsten carbide.
LIMITATIONS OF EDM
Low rate of material removal
The rate of material removal is low compared to conventional machining techniques. Due to the energy-intensive nature of the manufacturing process, an increase in manufacturing time impacts the total cost. For large-scale projects, EDM is ineffective, so companies choose alternative approaches.
Not every substance can be machined
Electrical discharge machining requires electrically conductive materials. Even though the process is technically stress-free, there is still a thermal process that can alter the metallurgy of the workpiece during machining.
Cost of the electrode
Die-sinking EDM requires a custom electrode that is the opposite of the feature. Machining electrodes may seem expensive at low production volumes, but this additional cost applies to many components at higher production volumes.
Footprint of carbon
Electro Discharge Machining is not an environmentally responsible method due to the amount of electricity required for its execution. Other forms of machining that require less electricity and are, therefore, less harmful to the environment are chosen over EDM as an increasing number of companies worldwide seek to implement carbon footprint-reduction initiatives.
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