Plane Surface Type
When you execute your measurement routine, the Roughness Scan command (RGHSCN) performs the following steps:
The controller drives the machine and measures point (S) with the support pin.
After the controller measures the point, the support pin is held in contact with the part.
The roughness measuring needle is dropped onto the part, and PC-DMIS performs the roughness scan.
After PC-DMIS successfully measures the roughness scan, the needle lifts and the support pin moves to the retract distance.
Small Hole
PC-DMIS positions the oblique cone in front of the hole, and then performs a self-centering of the oblique cone on the hole. This correctly positions the oblique cone inside the small hole.
To measure the Roughness scan, PC-DMIS draws out the needle and then contacts the part.
TIP Command
For the T1 tip type, PC-DMIS displays the TIP command in the Edit window as:
TIP/T1A0B0, SHANKIJK=0, 1, 0, SCANIJK=0, 0, 1, NORMALIJK=0, 1, 0, ANGLE=0
Scan ijk - This is the vector of the roughness scan line.
Normal ijk - This is the vector of the Start point.
If the Roughness scan command creates the Tip command, PC-DMIS generates the values of scan ijk and normal ijk to exactly match the values in the Roughness Scan command. If you insert the TIP command, PC-DMIS calculates the scan ijk and normal ijk based on its A and B angles.
Every time you place a part on the CMM, some change occurs in its position in the machine coordinate system. When you execute the Roughness TIP command, PC-DMIS determines the best tip angle based on the scan ijk and normal ijk values, and then updates the TIP command accordingly.
For T2 probe type, PC-DMIS does not correct the tip angles during execution to compensate for part placement errors. Small part placement errors are expected and self-centering resolves any mismatch.
Rotary Table
When you use the Horizontal Roughness sensor (90TR) with a rotary table, the Roughness scan command inserts the MOVE/ROTAB command in the Edit window. When you execute the Roughness scan command, PC-DMIS determines the best rotary table angle based on the scan ijk and the normal ijk values. The Roughness scan command also rotates the rotary table at the correct angle.
More:
Creating a Roughness Scan Command