Conventional EDM
Conventional EDM refers to the process of cutting, drilling, tooling and creating parts using electrical discharges or sparks to change the form of a material. It is used in applications such as injection mold tooling, micro hole drilling, internal splines, squares or hexes, blind cavities, intricate details, key ways, washers and scientific research apparatus. Industries such as aerospace, medical, tool and die, automobile and military all use conventional electrical discharge machining to achieve close tolerances and precision parts. While conventional machining methods may not be able to precisely machine metals such as stainless steel, copper and graphite, EDM machining can be applied to even the hardest materials. It is advantageous due to its ability to create complex and intricate parts with minimal deformation. There is no abrasive contact between the electrode and the part being working on and so the piece is smooth and burr-free upon completion. The electrodes used in the process of emanating high intensity electrical sparks are generally made from copper, graphite or tungsten. The electrode is connected to a power source which enables it to generate the electrical discharge required for the machining process. There is no direct contact between the electrode and the material being worked on. As the electrode and the product surface are brought closer together, the intense electrical field wears away the material in the desired pattern.
The EDM cutting or EDM drilling process usually occurs with the assistance of a dielectric fluid which is responsible for removing debris caused by the process. It also helps to prevent premature sparking and conducts the electricity between the electrode and the work piece. For advanced and complex pieces, CNC EDM uses CNC machines to guide, monitor and control the electrical discharges with the assistance of computerized software programming. This enables extremely close tolerances of even complicated pieces to be achieved and repeated. Products finished through EDM machining are not at risk of heat damage or surface distortion, and the finished edges of the product are smooth. Conventional EDM has an advantage over wire EDM as it does not cut all the way through a material and does not require pre-drilling. As with other types of electrical discharge machining however, the process is wearing on the electrodes and these require frequent replacement in order to ensure the most effective processing times. Sinker EDM, ram EDM and plunge EDM are all types of conventional EDM machining methods that are widely employed in parts processing.
