Machining high-strength materials through electrical discharge machining – EDM

Aero Engine as well as tool and die components are routinely subjected to extremely high levels of stress. This is why one key quality criterion is their material strength. High levels of strength, meanwhile, also dictate that the material in question will be difficult to machine. One technique of machining materials independently from their strength is spark erosion. The technologies of wire EDM and sinking EDM allow the high-precision production of geometrically complex components with very small interior radii. With the EDM technique, it is also possible to manufacture components with high-quality surfaces and low levels of subsurface damage.

The Fraunhofer IPT is using all of its skills and experiences with the application of EDM strategies in the development of innovative practical approaches, aiming to reduce subsurface damages to a minimum, to increase the components‘ technical life spans and to decrease the costs of the manufacturing operation. In our cutting-edge array of sophisticated equipment, we can test the results of our research departments and further deepen our understanding of the underlying physical processes, ultimately converting our knowledge into practical applications for mold and die manufacturing, engine production, precision engineering and medical technology.    

Our Services

  • Benchmarking and optimization of machining technologies
  • Production of customized small-sized batches
  • Integration into existing process chains
  • Analysis and reduction of thermal subsurface damages

Applications of spark-erosion sinking

Roughing of BLISKs

BLISKs (Blade Integrated Disks) mainly consist of titanium and nickel-base alloys. It is very difficult to machine or otherwise process them, due to the complex geometries of their surfaces and the problems of accessing the spaces between the individual blades. The technique of spark-erosion sinking enables the economical roughing operation of BLISKs.

Sealing slots in turbine blades

Spark-erosion sinking is a particularly cost-effective method of working on sealing slots in turbine blades.

Tools for plastic injection molding

plastic component, which means that it must be possible to remove the component easily out of the mold without damaging it. The spark erosion technology is capable of generating very fine structures and high aspect ratios.

Applications of spark-wire erosion

Filigree geometries

Wire EDM works without applying any force on the work piece and is therefore capable of creating filigree geometries of residual strengths below 50 µm with high aspect ratios. This comes in handy in – for example – the production of precise flexure hinges for high-precision positioning tasks.

Fir tree slots in turbine discs

Wire EDM can create fir tree slots in turbine discs flexibly, reproducibly and at low tool costs. The Fraunhofer IPT is currently researching the thermal impact of this manufacturing technology.

Cutting electrically
conductive ceramics

Structural components in the aviation industry are often made from high-strength ceramics. The material becomes electrically conductive – a requirement for the application of wire EDM– only when carbide particles have been added. We are currently researching the technology with a view to developing industrial applications.

Die cutting punches

Generally, only the technique of wire EDM is capable of producing complex cutting punches with a high degree of dimensional accuracy. The Fraunhofer IPT is using its comprehensive experience in the field to deliver new applications and process improvements.