TABLE OF CONTENTS Before defining the concept of automated dimensional measurements it is well to remember that integrated use of computers and sophisticated metrology/statistical software has been used to automate virtually every class of measurement equipment covered in this handbook. Laser scanning can measure thousands of data points at a time and compare those points to CAD data. CNC programs are now used to run preset measurement routines and across the board data is gathered, stored, displayed, analyzed, and printed automatically. Processes as well are automated with closed loop systems adjusting machine tools on the fly without human interaction. In short, today it is difficult to segregate a unique group of machines dedicated only to automated dimensional measurements. However, the major steps generally involved in automated dimensional measurements are:
Positioning the object and instrument in relation to one another, also termed staging when the object is placed on the instrument. In most cases this step establishes the mutual reference position of the object and the instrument for the subsequent measurement of a single, multiple or series of dimensions.
Travel, or movement, over a controlled or predetermined distance. That travel may be over a fixed distance, corresponding to the nominal size of the inspected part dimension and relying on the instrument's indicator to signal the amount of eventual deviations, or to a point of coincidence where the significant surface element of the object coincides with the fixed target (for example, mechanical or optical) of the instrument. In the latter case...
