Small Hole EDM
Small hole EDM (also known as fast hole drilling and start hole drilling) is a specialized tooling method that uses electrical energy to erode materials and produce holes in metals or parts that require close precision machining and repeatability.
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Applications of Small Hole EDM
Small hole EDM services are used in industries including automotive, injection molding, tool and die, medical and appliance with a wide variety of applications such as removing broken drill bits, small hole placement, hardened punch ejector holes and aircraft cooling holes.
Process of Small Hole EDM
Small hole EDM drilling employs a round, hollow electrode that rotates around a spindle, similar to a drill and drill bit. A generator or power source electrically charges the electrode, which then produces sparks or discharges, hence the term electrical discharge machining. The sparks erode the surface of the workpiece by creating microscopic pockets that eventually create a small hole. The workpiece is also attached to a power source and placed in a water-based dielectric fluid. As the electrode and the workpiece are brought closer together, an intense electric field is created, which serves to erode away the material of the workpiece. The dielectric fluid is responsible not only for conducting electricity during the process, but also for maintaining the temperature and flushing away the unwanted material debris.
The process of small hole drilling can be used as an independent drilling process on specifically designed work pieces or to make a through hole as a pretreatment for wire EDM, which requires a hole to start the cutting process. Small hole drilling capabilities extend from .03mm to 6.1 mm holes, and some can drill through 100 mm of soft or hard materials in less than ten seconds. CNC EDM machines are used to control the depth and location of the holes during the electrical discharge machining process, as well as CAD and CAM software to instruct the path of the electrode/s. The size of the hole created is controlled by the diameter of the electrode. Small hole EDM can be used for any hard or soft electrically conductive materials, which include stainless steel, titanium, aluminum, copper, carbide, and hard tool steels.
Advantages and Disadvantages of Using Small Hole EDM
Some advantages that come with using small hole drilling services include the ability to drill on curved or angled surfaces and through extremely hard or extremely delicate materials, as well as the ability to drill deep holes while remaining a fast, accurate, and affordable process. However, there are some drawbacks to using small hole EDM, which include a longer drilling time for large holes compared to conventional drilling, an inability to control blind hole depth, and significant electrode wear.