There are many advantage of CMM. It can do very precise and accurate measurement.
There are few advantage given below:
Less Setup Time
If we are doing inspection on surface plate then it is very time consuming activity. Where CMM can align a part in three axes in one go. It can orient a part in drawing direction with reference points easily.
Data can be comparing directly with drawing dimensions. This can create part reference system very easily with operator defined orientation also.
Machine can align part in one setup mostly so all error for different orientation can be calculate very easily.
CMMs are essentially universal measuring machines and need not be dedicated to any particular task. They can measure almost any dimensional characteristic of a part configuration, including cams, gears and warped surfaces. No special fixtures or gages are required. Because probe contact is light, most parts can be inspected without being clamped to the table.
With CMM all measurement results comes from one origin that is part coordinate system. Because of this errors are generally reduced and achieved good accuracy in comparison to the hand inspection tools.
Reduced Operator Influence
Due to computer controlled machine it can do the measurement of similar parts without operator influence. This will reduce the chances of errors in measurement and all parts can be measured with same process.
The above-mentioned advantages help make CMMs more productive than conventional inspection techniques. Furthermore, productivity is realized through the computational and analytical capabilities of associated data-handling systems, including calculators and all levels of computers.