Alignments and Datums

00:04

The alignment locks the position and orientation of the component, also known as the six degrees of freedom.

00:10

The first alignment type we will look at is PLP.

00:13

This stands for plane, line, and point.

00:18

Here we are going to use the top face plane to align the Z axis.

00:22

The line between the circle centers to align the X axis and the left hand circle center as the point.

00:29

All we need to do is use the dropdown boxes to select the required features and ensure the correct axis direction.

00:37

Any measurements taken from now on, we'll be using this alignment and the CAD datum.

00:43

Another geometric alignment we can perform is a RPS alignment.

00:48

Again, just use the dropdown boxes to select the first feature, then add your remaining features into the list.

00:56

Try to choose features that are spread across the part to give you the best alignment.

01:01

We will now choose the axis to lock.

01:03

Normally we follow the 3-2-1 rule.

01:06

So, in this case, we will lock three points in the Z, two in the X, and one in the Y.

01:13

The RPS alignment is now fully constrained.

01:16

If our component has no geometric features, then a Free Form Fit alignment can be used.

01:22

For this, we'll use the Dynamic Points editor tool to first place the points on the part, then choose Free Form Fit alignment.

01:30

We are now shown a table of the designated points and can accept these by pressing "OK" to create the alignment.

01:37

If you have scan data, we can also use this.

01:40

We will use the from Point Cloud alignment.

01:44

Simply select the correct Point Cloud source and PowerInspect will automatically align the Point Cloud with the CAD.

01:51

In some circumstances, a picked points alignment may be necessary to give us more control over the alignment parameters.

01:58

Here, we will add defined points when the Point Cloud matches the CAD.

02:03

First, set a catchment range for the target points by clicking and dragging on the Point Cloud, then select the corresponding surface to create a datum those points will get fitted to.

02:14

Once you've created your points, click the "Green Tick" to accept and then create the alignment.

02:20

Some drawings can have multiple datum structures that normally reference different parts of an assembly.

02:25

We take dimension nominals from our CAD datum by default, but this may not replicate some requirements on our drawing.

02:32

Here we can set the center of the circle as a datum.

02:36

Just create a datum from features and select your reference.

02:41

If we now change the coordinate system for the Ellipse, we can see the corresponding nominal is changed in the report.

02:50

To summarize, we have now seen how to align our CAD datum system with our machine using various techniques.

02:56

Also, using multiple datums to reflect drawings and change the nominal coordinates.