Current Help System: PC-DMIS CMM (View Core Help)

## Creating an Auto Edge Point

The Edge Point measurement option allows you to define a point measurement that is to be taken on the part's edge. This measurement type is particularly useful when the part's material is thin enough that a precisely controlled CMM measurement hit is required. Five sample hits are needed to accurately measure an edge point.

To access the Edge Point option, access the Auto Feature dialog box for an Edge Point (Insert | Feature | Auto | Point | Edge).

Auto Feature dialog box - Edge Point

With the dialog box open, depending on your situation, use one of these methods to create the feature:

Creating by Using Surface Data on the Screen

To generate an edge point using surface data:

1. Click on the Surface Mode icon .

2. With the mouse, click once on the surface near the edge where you want to create the Auto Edge Point.

3. Verify that the correct surface has been selected. The dialog box will display the value of the selected edge point and vector once the point has been indicated. The direction of the surface normal vector is determined by the side of the part that is accessible to the probe. If both sides of the part are equally accessible, the normal from the CAD data is used. The Flip Vector icon lets you change the direction of the approach.

4. Click Create to insert the feature in to the part program. If additional mouse clicks are detected before you click the Create button, PC-DMIS will overwrite the previously displayed information with the new data.

Creating by Using Surface Data with the CMM

To generate an edge point using surface data with the CMM:

1. Touch near the desired edge of the part using the probe.

2. Try to make the shank as normal to the surface as possible.

PC-DMIS will pierce the CAD surface closest to where the probe touched. The displayed X, Y, Z values reflect the closest CAD edge to the hit, not the actual hit. The I, J, K reflects the surface normal vector.

If a CAD edge is not found, PC-DMIS will display the closest point and ask that additional hits be taken.

If a second touch is taken on the opposite surface prior to clicking the Create button, PC-DMIS will alter the location values as appropriate. The displayed vectors, however, will remain constant.

The Find Noms option should be selected from the Mode list for this measurement method. See the "Mode List" topic in the PC-DMIS Core documentation for additional information on nominals.

Creating by Using Wire Frame Data on the Screen

Wire frame CAD data also can be used to generate an edge point.

To generate an edge point:

1. Click near the desired wire on the edge side (not within the boundary of the top surface). PC-DMIS will highlight the selected wire.

2. Verify that the correct feature has been selected.

The probe approach is always perpendicular to the line, as well as perpendicular to the current probe centerline vector. The probe will approach from the side of the edge that was clicked on. The dialog box will display the value of the selected edge point and the vector once the wire has been indicated.

If an additional touch is necessary, click on the opposite wire of the (normal) surface.

Creating by Using Wire Frame Data with the CMM

To generate an edge point using wire frame data with the CMM :

1. Touch near the desired edge of the part using the probe.

2. Try to make the shank as normal to the surface as possible.

PC-DMIS will pierce the CAD wire closest to where the probe touched. The displayed X, Y, Z values reflect the closest CAD edge to the hit, not the actual hit. The I, J, K reflects the surface normal vector. If a CAD edge is not found, PC-DMIS will display the closest point and ask that additional hits be taken.

If a second touch is taken on the opposite surface prior to clicking the Create button, PC-DMIS will alter the location values as appropriate. The displayed vectors, however, will remain constant.

The Find Noms option should be selected from the Mode list for this measurement method. See the "Mode List" topic in the PC-DMIS Core documentation for additional information on nominals.

Creating without Using CAD Data

If the edge point is to be generated without the use of CAD data:

- The first three hits that are taken will indicate the surface vector nominal.

- The next two hits will find and display the other vector. This value indicates the opposite direction of the CMM approach vector (pointing away from the surface).

- The last hit (sixth hit) will indicate the actual edge point location.

Creating by Keying in the Data

This method allows you to key in the desired X, Y, Z, I, J, K values for the edge point.

1. Type in the desired X, Y, Z, I, J, K values for the feature into the dialog box.

2. Click Create to insert the feature into your part program.

See the "Mode List" topic in the PC-DMIS Core documentation for additional information on nominals.