Micro EDM
Micro EDM is a tooling method that uses electrical energy to erode materials at the micron level and thus produce very small holes and structures. Micro EDM services are highly-effective on hard materials and difficult surfaces and include micro wire EDM, micro sinker EDM and micro small hole EDM. Micro EDM is used to machine parts from .1 to 1 mm in size; the size of these parts makes it impossible to form them through normal semiconductor processes. Micro EDM can machine any electrically conductive material, including silicon, tungsten and stainless steel. With micro EDM technology being used in industries including aerospace, robotics, nuclear, medical, textiles and electronics, wide-ranging applications for micro EDM services include fuel injection nozzles, miniature gas turbines, micro-compressors, optical devices and micro-tools.
The actual micro edm machining is accomplished through sparks, which are electrical discharges that can generate heat anywhere from eight to twenty thousand degrees. Wires or electrodes, hollow cylindrical metal elements typically made of tungsten or metal graphite, are used to generate the series of sparks. The micro EDM process uses smaller electrodes with high rigidity and rotational speeds. There is no actual contact between the electrode and the work piece (the material being processed), but rather a conductive gap that is established and maintained between the electrode and the material. This process takes place in a bath of dielectric fluid, which prevents premature sparking and conducts electricity between the electrode and the work piece and then flushes out material debris from the gap. Equipment required for micro edm includes a pulse generator, to produce small pulses of input energy, and high precision systems such as CNC machines, CAD and CAM software that are used to guide, monitor and control the electrical discharge machining process.
Micro EDM has advantages over conventional machining processes such as metal etching because it is accurate, cost-effective, clean, repeatable and flexible. In addition, 3D structural micro features can be produced, as well as holes and 2D machined micro-parts. However, there are some disadvantages which include significant electrode wear that can lead to inaccuracies in machining. A new technology that has been developed in the micro EDM field is batch micro EDM, which utilizes multiple electrodes to machine mass materials. Special electrodes are required, which has led to the development of LIGA-fabricated electrodes. The LIGA fabrication process produces high aspect ratio molds for electroplated structures, such as copper electrodes, utilizing x-ray lithography. Batch micro EDM is advantageous because it is a higher-efficiency method for machining mass holes or parts.