Manual impeller manufacturing, 3 axis roughing in NX CAM

This entry is part 2 of 4 in the series "Impeller manufacturing" NX CAM training 3-5 axis

This instruction shows the process for creating roughing operations for an impeller (as a part of impeller manufacturing series). It can work as a training material for 3 axis manufacturing.

Reasons for manual 3 axis.

During my tests in impeller manufacturing, manual roughing operations have shown better performance compared to 5 axis. The difference in performance decreases, when areas to manufacture are difficult to reach from one position. In that case a combination of 3 axis and 5-axis (NX-turbomachinery) looks like an optimal choice. The main point in performing the 3 axis operations are axis position and cutting zone limitation.

Step-by-step instruction.

3 axis operation from top.

First of all, check how much material can be removed using cavity mill operation with the tool axis parallel to impeller rotation axis. Some blade geometries allow removing a large amount of material with a large-diameter tool.

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Impeller model

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3-axis operation from top


Defining the views.

Next thing would be to “catch” the view in the position, when you can see more material removed (usually a position when you can see most of bottom surface). You may require making two views for two operations, like on the example bellow (the material for removal is surrounded with lines).

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Manufacturing zone 1

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Manufacturing zone 2

Save both of the views in the part navigator (in this example they are named: cavity 1, cavity 2).

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Removing material between blades.

  • Set the view to the first cavity operation (do not rotate it after this)
  • Create a new Cavity mill operation
  • Define the trim boundaries in the following way:
    • Filter type – Curves
    • Trim side – Outside

      manual impeller manufacturing

      Boundaries definition

    • Plane – Manual, set the plane to view plane
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    • Select the curves as shown on the picture
      NOTE: curves can be taken from the impeller’s edges or constructed manually.

      manual impeller manufacturing

      Boundaries defined, first operation (1)

      manual impeller manufacturing

      Boundaries defined, first operation (2)

    • Approve the boundaries dialog
  • Define the tool axis to be perpendicular to current view
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  • Set the operation to use InProcess workpiece
  • Generate the operation
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Workpiece before operation

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Workpiece after operation

Removing material between blades, second operation.

Repeat the actions for the second operation

  • Use second view for Cavity 2
  • Example of boundaries definition:
    manual impeller manufacturing

    Boundaries defined, second operation (1)

    manual impeller manufacturing

    Boundaries defined, second operation (2)

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    Worpiece after operation

Video instructions for impeller manufacturing.


Before creating a NX turbomachinery operation, consider checking manual operations. It can save some production time.

Let me know what you think. Have you used any methodologies for optimizing production time for CAM operations?

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