To provide a collision-free path for your measurements, you need to use ClearanceCube and Feature Based Measurement (FBM) concepts when you create your measurement routines. For information on how to use ClearanceCube, see "Using the ClearanceCube".
Features and commands can be of the following types:
ALWAYS Measured - Use this option if, as a PC-DMIS application programmer, you would like to always measure certain features.
You must create these features outside of a group.
Measure only if required - Use this option for FBM if, as a PC-DMIS application programmer, you want to measure a feature only if the selected dimension requires it.
You must create these features and commands in a group.
FBM Concepts
Each group can measure features on one side of a part. You can use a MOVESET command at the beginning and activate ClearanceCube motion at the starting face (or set it to off for the ending face). You can now use any method in PC-DMIS to measure features on that side of the part. PC-DMIS may not activate the ClearanceCube motion for these features.
We recommend that you use the Avoidance Move function between features on each side of a part. This provides you with collision free paths between features. When you complete all measurements, use a MOVESET command and turn the ClearanceCube motion on for ending face (off for starting face).
If you assign datum feature reference letters to the datum features, that assignment should be within the group that measures the features.
You can also activate ClearanceCube for all features in a group instead of using a MOVESET command.
When you insert the MOVESET command at the beginning and end of a group, it's similar to how a car enters and exits a highway. The command at the start tells PC-DMIS to enter the group of features and use the ClearanceCube command to position the tip in preparation to measure any feature on that side of a part. Once all measurements are complete, PC-DMIS positions the tip to the ClearanceCube face. This allows the tip to safely move to any other face or probe changer.
You can create dimensions in the group where they are measured, or create them in a separate group. You can also group dimensions according to an operation, cell, or manufacturing tool. This may help you select a complete group of dimensions in a mini routine.
Alignment Concepts
Carefully consider how you create alignments. For FBM, you select a dimension to report, and FBM marks the related features.
FBM marks all of the required features to create the appropriate alignment. In PC-DMIS, you can base alignments on the recall of a previous alignment. In those cases, FBM also looks at those alignment dependencies and marks everything required to create the recalled alignment.
If an alignment constrains all 6 Degrees of Freedom (DOF), we recommend that you recall the STARTUP alignment rather than the previous one. This breaks the dependency chain, and PC-DMIS only measures those features.
Measurement Routine Variables
PC-DMIS may use variables to measure a family of parts. FBM supports variables.
It is recommended that you define and use the variable that is in the same group in which you want to measure the feature.
Commands Outside of Groups
PC-DMIS always marks and executes every command that is not part of any group.
If you need variables (character strings or numbers) for any reason, you may want to define them outside of a group. You can place anything that must be executed (such as non-motion commands, tracefields, and generating strings for output file names) outside of a group.