CMM Operation and Programming

There are various ways in which the probe might be positioned that varies from manual operation to the direct computer control (DCC). Computer-controlled CMMs should be programmed and they should operate similar to CNC machine tools. In this section aspects of CMMs taken into account are following:

1. Types of CMM controls; and

2. Programming of computer-controlled cMMs.

On the basis of operating & controlling of CMM, it might be classified in the four following ways:

1. Manual drive,

2. Manual drive with computer-assisted data processing,

3. Motor drive with computer-assisted data processing, and

4. Dcc with computer-assisted data processing.

The probe is physically moved though human operator along the machine's axes for making contact with the part & the measurements are recorded in manual drive CMM. The three orthogonal slides are designed to be closely frictionless to allow the probe to be free floating in x, y, & z-directions. A digital readout provides the measurements that the operator may record either manually or with paper printout. Only operator is permitted to carry out calculations on the data that involves the enumeration of the center and hole diameter.

Data processing & computational capability for carry out the calculations that are needed to evaluate a given part feature are provided by a CMM along manual drive CMM with computer-assisted data processing. The different types of data processing & computations are ranging from simple conversions among US customary units & metric to more complexes geometry calculations, such like determining the angle among two planes. The probe is free floating and allows the operator to bring it into contact along the desired part surfaces.

Electric motors are utilized in a motor driven CMM along the computer-assisted data processing to drive the probe along with the machine axes under the operator control. The motion is controlled though joystick or similar devices. The collisions among the probe and the part are decreased by low-power stepping motor and friction clutches.

CMM with direct computer control (DCC) operates just as a CNC machine tool. This is power driven & the movements of the coordinate axes are controlled though a dedicated computer under program control. Several data processing is performed by the computer and this also keeps record of the measurements made throughout inspection. DCC CMM needs a part programming facility.