This is article 3 of a 3 part series that describes the steps and considerations for milling a multi-bladed part using NX CAM Turbomachinery Milling.
Part 1 - Setup
Part 2 - Roughing
Part 3 - Finishing
Blade finish shares some aspects with the Multi blade roughing (see part 2 of this series): Stocks, Cut levels, Tool axis orientation (beside “Rotate about” control). The different aspects are detailed below.
Blend Finishing shares some aspects with the blade finish: Stocks, Tool axis orientation. The different aspects are detailed below.
The range of the step over’s is defined by two parameters:
The default method of ‘Automatic’ tool axis provides quick and good gouge free smooth orientations along the tool path. However, to get smoother results as well as to avoid cases where the ‘Automatic’ method fails to locate gouge free orientation (hence tool path is trimmed and reconnected by NCMs) in NX7.5.2 we offer a new method “Interpolated Vector”.
Since this option is in preview state in 7.5.2 you will need to set a new ENV: UGII_CAM_5AXIS_BLADE_FINISH_INTERP with the value 1. (Update: this feature is no longer preview as of NX8.) Limitations in 7.5.2 are detailed at the end of this section
The concept here is that the user can set the tool alignment along the lowest cut level and those alignments are reused for the upper cut levels in a parametric manner.
After defining the geometry, stocks and tool, change the Tool Axis orientation to ‘Interpolated Vector’:
The system will spend some time to generate the lower rail along which you can define the orientations and the system points defined by a yellow arrow:
In case the geometry is not contiguous or tool not defined you may get some warnings / error messages same as during tool path generation.
You will also get the Interpolated Vector dialog:
There are a few activities you can do at this stage:
To remove this dynamic preview – uncheck the checkbox.
To clear those vectors – refresh the screen (use refresh command or F5).
Tilt Clearance Angle is not active in NX7.5.2.
In NX8 it will provide same safety clearance from the part as in Automatic tool axis.
Reset to Default from the dialog will delete all user points and will reset all system points to the default orientation.
When copying an operation to another file or copying it to be used for a different blade / splitter in the current file it is recommended to use it to avoid applying irrelevant settings.
The list in the dialog contains all points. For each point it shows:
1. Check the Preview checkbox.
2. After invoking the Interpolated Vector dialog press the display Preview.
3. Based on red tools decide where you want to locally manipulate the orientations. Select an existing point or add a new one.
4. Press F5 to clear the screen from the static preview.
5. Rotate the tool at that point till you get it and its nearest instances collision free.
6. Press the display Preview again and see where the next location that needs manipulation is and continue this way till you get the expected alignments all over. Note that sometimes you may manipulate orientations to minimize tool axis changes. For that you can Copy Orientation from previous / next point.
7. Press OK in the dialog and Generate the operation. On the lowest cut your tool path is most likely OK, however upper cut levels may be gouging so the tool path is trimmed and reconnected by NCMs:
8. Go back to the Interpolated Vector dialog and change existing point/ add new ones to increases the margins there:
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|Eddy Finaro started his professional career as a mechanical engineer working with various airborne mechanical systems. He spent 8 years as an Application Engineer and Product Manager with Cimatron. Since joining Siemens PLM 5 years ago he has worked as an NX CAM Product Manager responsible for complex milling. His expertise is in 3- and 5-axis milling, particularly complex parts such as impellers, blisks, and airframe parts, etc. Eddy holds a M.Sc. degree in Aerospace Engineering. On his free time Eddy enjoys Mountain Biking, Hiking and mentoring a First Robotic Competition Team.|