The applications of EDM small hole drilling might be expected to be very limited in scope. Indeed, it would be difficult to think of a more innocuous phrase than small hole drilling, a phrase befitting a niche technology. But this belies the reality of EDM small hole drilling as a machining method used in many industries, industries that value precision and the characteristic of EDM to drill through very tough materials. Its use in gas turbines is the best illustration of what EDM small hole drilling can do in your industry.
Gas Turbines and Hole Popping
A gas turbine is a highly adaptable type of internal combustion engine that converts the impulse generated by the combustion of compressed air and fuel into useful work. How this work is harnessed determines whether a gas turbine is part of a power generator or a jet engine. A jet engine harnesses the jet of exhaust gases created by combustion for thrust, for example. Common to all gas turbine engines, however, is a turbine located downstream of the combustion chamber, which gives them one of their most important characteristics—they are self-sustaining. The compressor that allows for efficient combustion is powered by the electricity generated by the turbine. But for such a critical role, gas turbines are subjected to an extremely hostile environment of intense heat and centrifugal forces, and it is no surprise that the alleviation of this problem has been a major impetus in gas turbine development.
The primary limiting factor in gas turbine development has been heat, and research looking to alleviate the problem of heat has focused on two areas. One area is material science. Since the problem of heat was recognized, many cutting edge alloys have been developed that can resist both the heat and centrifugal forces found inside a gas turbine. But today, this is not enough. Temperatures in modern gas turbine engines can exceed the melting point of even these advanced alloys. This prompted the second wave of gas turbine development, which focused on cooling methods. One of the most prevalent cooling methods is called film cooling. In film cooling, air is directed through holes drilled on the surface of a turbine blade, creating a film on the surface of the blade that acts as a barrier to super-hot exhaust gases. Modern turbine blades combine advanced, adamantine alloys with cooling holes, to which only EDM small hole drilling is suited.
The characteristics that suit EDM small hole drillings to applications such as turbine blade cooling hole drilling are its ability to drill through very hard materials, an absence of machine tool pressure, and pinpoint accuracy. An EDM electrode never makes physical contact with its workpiece, which means that an electrode will work regardless of how hard the workpiece is. This lack of physical contact also eliminates machine tool pressure, which can prevent working on a delicate workpiece like a turbine blade, and create burrs and other deformities. This lack of machine tool pressure also contributes to the great accuracy of EDM small hole drilling. Below are just some of the applications of EDM small hole drilling. This list is not comprehensive, but only suggestive of hole popping’s great versatility.
Fuel injection has essentially supplanted carburetion in automotive engines. Due to the superior precision with which fuel can be delivered to a combustion engine, fuel injection engines boast superior fuel economy, less toxic emissions, and require less maintenance than engines using carburetion. A fuel injector uses very small nozzles to atomize gasoline or diesel fuel, ensuring a precise and predictable delivery of fuel. This is why EDM small hole drilling is the favored machining method. A lack of precision in the diameters of nozzle openings could hamper proper functioning of a fuel injector.
EXCETEK has manufactured small hole drilling EDM since 2006, the hole drillings have CNC series and for general purpose series. As a leading drilling machine manufacturer, we have a strong R&D team to keep improving our products to meet the highest standard of our clients. If you are interested in learning more applications and specifications about small hole drillings, welcome to contact with Excetek, we are looking forward to corporate with you.