- Manual impeller manufacturing in NX CAM
- Manual impeller manufacturing, 3 axis roughing in NX CAM
- Manual impeller manufacturing in NX CAM, 5 axis (semi)finish
- Manual impeller manufacturing in NX CAM, 4 axis mill-turn
NX CAM multi-axis has a potential to save resources by making complex parts in 4 axis instead of 5 axis. This example shows the process for making a CNC toolpath for an impeller on a mill-turn machine (with simultaneous 4 axis). It will be useful for practicing skills in multi-axis milling and for CNC programmers who support mill-turn machines.
Why replace 5 axis with 4 axis.
Quite many geometries, which are made in 5axis can actually be made in 4 axis. In case it is a complex turn-mill part (like impeller) it can make sense to manufacture it in one single setup on a turn-mill machine. This can replace the (quite commonly used) process, when the workpiece is done on a lathe and then is sent to 5 axis milling machine. The possibility to select methods, gives more flexibility in production planning, that potentially can result in savings.
“Interpolate vector” gives flexible axis definition.
Here I describe the method, which is mainly based on the use of Interpolate vector axis position. It involves quite a lot of manual work and requires basic understanding of multiaxis. Technique is similar to what was shown in previously for 5 axis, with some corrections for 4 axis. Roughing is done similar to 3 axis rouging tutorial.
In my example of 5 axis I was defining the vector to be perpendicular to view. In this case we do it in the same way, but we only rotate model in 4 axis. Normally the rotation axis of a turn-mill part is Z.
- Use F8 to align the view
- Use axis rotation (put mouse to the right or left side when rotation is on)
Check the model.
First of all, rotate the model around Z axis, and find out if all zones are reachable on 4 axis machine.
Define Surface area parameters
- Start a new multi-axis operation with Surface Area drive method
- Specify the Drive surface
- Specify the Cut direction
- Set the method Cut Pattern to Zig
- Press Display under Preview (the preview should look similar to one on the picture)
- Press OK
Defining multi-axis options.
- The projection vector can be kept as Tool Axis (default)
- Set the axis to Interpolate vector (Interpolate vector dialog opens)
- Rotate the model around the Z axis until you see that a zone next to the vector will not cause the collision
- Repeat the actions for all system vectors
- If required, add new points and set directions (for this impeller I needed 2 more)
- Set Interpolation method to Smooth
- Press OK
- Generate the operation
In case the correct rotation is followed, the operation would perform the correct 4 axis movements.
When making similar geometry, consider the following:
- In some impeller geometries, you can reach all areas in 4 axis, but you would require a smaller tool (compared to 5 axis). That means that sometimes 5 axis operations are more productive.
- The surface finish can be worse (again, compared to 5 axis), because in many cases 4 axis would not allow keeping a constant angle to the surface.
Did you experience problems when moving from 5 to 4 axis? In what kind of parts?