HEIDENHAIN IK 5494-2D - Manual (Page 132)

110 QC5200 Series User’s Guide
Creating a datum automatically
The Pattern Finder probe is often included in programs to create part datums automatically when measur-
ing a series of unlike parts or when measuring parts without fixturing. In these cases, the Pattern Finder
probe is used to find the landmark features necessary to construct a preliminary datum, and then used again
to find the precisely located
datum features for the measure-
ment datum.
The steps described above will be shown in the following example of creating a datum for a printed circuit
board without fixturing. First, the two bottom corners of the board will be found and used to create a
preliminary datum, then two fiducials will be used to create a precise measurement skew and datum.
Find and teach landmark features
The programmer moves the stage to position the bottom-right corner of
the printed circuit board under the video camera. The pattern probe is
then positioned over the corner, re sized and taught the corner pattern.
The probe is fired to return a point at the center of the pattern.
The programmer then moves the stage to position the bottom-left corner
of the printed circuit board under the video camera, then teaches and fires
a probe to return a second point.
Create preliminary skew and datum
The two corner points are selected and used to construct a preliminary
skew.
The two corner points are selected... and used to construct a preliminary skew
The preliminary skew extends from corner to corner