NX12 Manufacturing Fundamentals (Milling)

Create MFG Assembly

Make an assembly model that reflects your machine setup. For our class, we will use the vise and parallel models on the Machine Setup page. Use only the tools listed on the “Tool List.” You can use other drill bits (except metric, ask about these).

First create the geometry of your finished part. Then create the geometry of the unmachined “blank.” Assemble these two models into the same position in the mill setup.

When the assembly is finished, you will:

Face Milling

Face milling is a planar operation used to clean up a flat face of a part. In our example the injection mold needs a flat surface at the parting line.

For this class, we will use Face Milling with Boundaries. To use this operation, you define a milling boundary from your part geometry. You can then mill at that level or select a plane. Here are examples of each:

Cavity Mill

Cavity mill is a good all-purpose milling operation type. To avoid cutting “air” you will need to use IPW.

Sometimes the default axial depth of cut will be too much for a tool. For instance, the .125 end mill we use in lab has a maximum full slot depth of cut of .050. To ensure the tool does not take a deeper cut that .050 we can set a “maximum cut level depth.”


  • Use standard workpiece as geometry (blank with workpiece inside)
  • Use 90 deg brazed carbide router bit
  • Use Planar Profile operation
  • The video also shows how to use a trim boundary to prevent from deburring the sprue location on the mold. If the sprue location is deburred, it will leak during the molding process.
  • Specify part boundaries
    • Type is Curve/Edges
    • Open type or closed
    • Plane automatic
    • Tool position is tanto
    • In the video example the floor plane is 0.050 below the top surface.
    • Part Stock is negative amount (on path settings panel, cutting parameters dialog box). This value MUST be less than (absolute value) the distance to the floor plane or you will cut a “V” shape with the bottom of the tool.


We will used a “Fixed Contour” to engrave the surface of a block. You can use existing curves to drive this operation. Here, we will import an AutoCAD drawing onto the block to use as our drive geometry. It will help things go smoothly if your AutoCAD entities are in the scale and CSYS as the destination NX model.

Spot Drilling

Here is an example of spot drilling. Notice below that the drill would rapid into the part if the holes were to be drilled before the steps. This video shows how to avoid this and how to use a “predefined depth.”

Peck Drilling

How to create a peck drilling operation. Notice the same problem with rapid motion into the part if the programmer does not take care to avoid it. Also, setting the peck depth is not really intuitive.