INTRODUCTION
With the advent of numerically controlled machine tools, the demand has grown for
some means to support these equipment. There has been growing need to have an
apparatus that can do faster first piece inspection and many times, 100% dimensional
inspection. The Coordinate Measuring Machine (CMM) plays a vital role in the
mechanisation of the inspection process. Some of the CMMs can even be used as layout
machines before machining and for checking feature locations after machining.
Coordinate measuring machines are relatively recent developments in measurement
technology. Basically, they consist of a platform on which the workpiece being measured
is placed and moved linearly or rotated. A probe attached to a head capable of lateral and
vertical movements records all measurements. Coordinate measuring machines are also
called measuring machines. They are versatile in their capability to record measurement
of complex profiles with high sensitivity (0.25 m) and speed. In this unit, we will
discuss the principle and the working of a Coordinate Measuring Machine (CMM)