Creating an alignment

With only a few exceptions, all traditional alignments will be created in the following order:

1. Inspect a plane or other suitable feature for a Level operation.
   
2. Level to the feature.
   
3. Inspect a line or other feature suitable for an Align operation.
   
4. Align to the feature.
   
5. Inspect or construct a point.
   
6. Set the origin to the point.
   

Various options will be discussed at each step of the way.

When these steps are finished, a determinate (finished) alignment is complete.

Level command - Set Primary Datum

The Level command is the first step in creating a reference frame from existing part features.  If a plane is used as the Level feature, it establishes the working plane/Primary Datum Feature and controls one translational degree of freedom as well as two rotational degrees of freedom. 

Allowable features for the Level command are:

1. Plane
   
2. Cylinder
   
3. Cone
   
4. Line

If a cylinder, cone, or line are used, only two rotational degrees of freedom are controlled.  Another method will be required to set the translational degree for freedom (datum zero).  This is described here.

1. Using the appropriate Feature tools inspect or construct the feature to be used as the primary "level" alignment.  Points should be spread over the entire surface to minimize the effect of local form errors.
   
2. Select Alignment tab | Traditional group | Level
   

1. Select the feature to be used by drag-n-drop from the Feature Database, or by selecting the feature from the CAD view.
   
2. Select the appropriate direction option.  In many cases, this dialog will already be filled in with the necessary information using the nearest axis to the measured feature.  This is the direction as defined by the print/CAD and is not necessarily the same as the machine axes.
3. Check the Set Origin to Feature checkbox as appropriate.
   
4. Click OK
   

1. Using the appropriate feature tools, inspect or construct the feature to be used as the secondary "align" alignment.  Points should be spread over the length of the feature to minimize the effect of local form errors.
   
2. Select Alignment tab | Traditional group | Align
   

1. Select the feature to be used by drag-n-drop from the Feature Database, or by selecting the feature from the CAD view.
   
2. Select the appropriate Working Plane.  If this line is used to stop rotation around the Z axis, the Working Plane would be the XY plane.
3. Select the appropriate direction option.  In many cases, this dialog will already be filled in with the necessary information using the nearest axis to the measured feature.  This is the direction as defined by the print/CAD and is not necessarily the same as the machine axes.
4. Check the Set Origin to Feature checkbox as appropriate.  As an example, note that an X axis direction line sets (typically) the Y axis origin.
   
5. If changes were made, click Apply.
   
6. Click OK
   

1. Using the appropriate feature tools, inspect or construct the feature to be used as the "origin" point.
   
2. Select Alignment tab | Traditional group | Set Origin
   

1. Select the feature to be used by drag-n-drop from the Feature Database, or by selecting the feature from the CAD view.
   
2. Select the appropriate axis options.  Be careful to select only the required axes.  For example, if the Z axis was set on a plane, the point would have to be measured at some "depth" in order to touch the side of the part.  Using the Z axis of the point would move the Z origin below the top surface.
   
3. The Offset boxes allow the programmer to "shift" the datum point by a nominal value from the measured feature.
   
4. If changes were made, click Apply.
   
5. Click OK
   

The Offset Align command is an alternative second step in any alignment and sets the secondary axis of the Secondary Datum based on an offset distance from a measured or constructed point feature.  A temporary line is created from the current origin in a direction such that the line is at a specified offset distance from the reference feature.  The Offset Align command controls one (the final) rotational degree of freedom, and normally controls one translational degree of freedom.

Allowable point features are:

1. Point
   
2. Circle
   
3. Sphere
   
4. Slot

1. Using the appropriate feature tools, inspect or construct the point feature to be used as the secondary "offset align" alignment.
   
2. Select Alignment tab | Traditional group | Offset Align
   

 

1. Select the feature to be used by drag-n-drop from the Feature Database, or by selecting the feature from the CAD view.
   
2. Select the appropriate Working Plane.  If this line is used to stop rotation around the Z axis, the Working Plane would be the XY plane.
3. Enter the nominal offsets of the reference feature in relation to the current origin.
4. If changes were made, click Apply.
   
5. Click OK
   

In this example, the X axis was aligned, offset from the circle center, to the offset distances entered in the Offset Align dialog.

Please note that in order for this to work properly, the proper origin must be set first.  This means that instead of the normal Level/Align/Origin sequence, the sequence will be Level/Origin/Align.  Although this is a complete alignment, CMM-Manager sees the "Align" as the last command and does not recognize this as a determinate alignment.  Because of this, the automatic Sync CAD does not occur, and the programmer must execute a Sync CAD command after the alignment is complete.