ComputerAided_Design_Engineering_amp_Manufactur.pdf

FIGURE 2.21 CMM planning requirements and tasks.
• A methodology for the assignment of set-ups, part coordinate systems, probe configurations,
sampling size, and minimization of probe travel is important for the optimization of CMM
inspection in terms of cycle time.
• A methodology for collision-free path planning in order to realize feasible inspection programs
• An interface to the CMM in the form of a neutral programming language such as DMIS which
will carry the final inspection commands for any CMM.
To realize the final objectives of a computer-aided inspection planning system for the CMM, there
are generally five inspection tasks to be carried out, as outlined in Figure 2.21.
1. The first inspection task is to interpret the measurements required for the part based on the
product model representation. Interpretation would include recognizing geometric elements on
the part to be measured for the evaluation based on their associated GD&T specifications, and
determining the evaluation functions to be used and the output to be produced by the CMM.
2. The second inspection task is to determine the setup of the part on the CMM for inspection.
The major consideration is the minimum setup orientation for the part. The task plan for the
CMM will include the part coordinate systems to be used for the orientation, the elements to
be measured or constructed to create the part reference, and the elements that are to be measured
in the setup.
3. The third inspection task is to assign the probe configurations and operation parameters for the
measurement elements. Major considerations would include assignment of suitable probes, minimization
of the probes assigned, and the sampling points required for the measurement.
© 2001 by CRC Press LLC