Perpendicularity reports whether a plane, line, or axis is at 90 degrees to a datum plane or axis. Use the GD&T Perpendicularity item to determine the perpendicularity of a feature to a specified datum.
To create a GD&T Perpendicularity item:
- Open a Geometric group in the inspection sequence.
- Click Geometry tab > GD&T panel > Orientation > Perpendicularity.
- Enter a Name for the item.
- To exclude this item from the report, deselect the Output in report check box.
- To restrict the available datums to items that are close to the perpendicular of the feature you want to inspect, select the
Use angular tolerance to filter the available features check box, and enter the maximum angle by which the datum items can vary from the feature's perpendicular in the
Angular tolerance box.
To show all datum items in the list, deselect the Use angular tolerance to filter the available features check box.
- Enter any extra information about the item in the Comment box.
- Click Next to display the Feature Definition dialog.
- In the
Feature list, select the item whose perpendicularity you want to report. You can select a plane, a line or the axis of an item, such as a cylinder.
The diagram at the bottom-right of the dialog illustrates the shape of the tolerance zone.
- In the Primary datum list, select the datum against which you want to determine the perpendicularity of the Feature.
- To check the item's perpendicularity against a second datum, select the
Use datum check box and select the datum in the
Secondary datum list. Click
to
select an item from the CAD view using the mouse.
- Enter the width of the item's tolerance zone in the
Tolerance box. The control frame at the top of the dialog summarizes the tolerancing requirements.
This GD&T item is length-dependent. The whole Feature must lie within the tolerance zone to be in tolerance.
- Click
Next. The results of the GD&T calculation are displayed in the
Result Preview dialog. If the result is:
- Accepted, the measurement is in-tolerance.
- Out of Tolerance, the measurement is out-of-tolerance.
- Not Calculated, the measurement cannot be calculated because one or more of the selected features or datums is unmeasured.
- Click Finish to create the item and save the results, or click Back to change the item definition.
The perpendicularity value is the thickness of the zone that just contains the entire feature. If the thickness of the zone is less than or equal to the width of the tolerance zone plus any bonus you have specified, the feature is within tolerance.
The accuracy of the result is dependent on the length of the feature because shorter features have more freedom to rotate within the tolerance zone.