Electro-Chemical Machining (ECM)

Electro-Chemical Machining or ECM is a rapid, cost-effective, stress-free machining process that produces a high-quality finish.  It is specifically well suited for removing material in complicated geometry by anodic dissolution from hard to conventionally machined materials.  BN is one of the few companies in the world that use this process and has utilized this process for over 40 years to manufacture turbine blades, turbine nozzles, and internal complex shapes for aerospace, defense, cryogenic, and advanced energy industries.


U.S. Navy photo courtesy of Huntington Ingalls Industries by Ricky Thompson/Released

ECM Turbine Wheel

ECM is the only process that can accommodate single-piece blisks (bladed turbine disk) with the extremely close spacing shown here utilizing high-strength nickel alloys needed for high-temperature turbines.  It provides the following advantages.

  • No stresses are introduced to the part during the process
  • High power density turbine design not constrained by large spacing needed for milling tool sizes and deflection
  • Consistent and accurate reproduction of turbine blade shapes and other fine features with tight spacing
  • No wear on the machine tool
  • Fine surface finish exceeds performance needs with no subsequent processing.

Turbine Nozzle Rings

ECM can also make complicated internal shapes at shallow angles in high-strength materials as shown in the rocket engine turbopump nozzle rings.  These nozzles would be incredibly difficult to mill conventionally at such a shallow angle and would take significantly longer than ECM.


Thrust Reverser Actuator for the JT9D Engine

ECM is used to produce the Thrust Reverser Actuator for the JT9D Engine which is used on various civilian aircraft including the Boeing 747.  The ECM tool shown is used to remove material from the center of each of the three helical lobes on the Thrust Reverser Actuator. Removing the material from the center of the lobes reduces the weight and inertia of the rotor. ECM is the only process that can perform this operation at a reasonable cost.

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