The plate also provides an excellent bearing surface and dampens vibrations. The second and third components of the CMM are the probe and linear encoders. The contact probe uses an industrial ruby tip to trigger the measurement sensor. When the ruby makes contact, the sensor instructs the computer to record it s' position. The probe is multidirectional and can approach the part from a variety of directions without moving the part.
Probe tips come in a variety of shapes and sizes to accommodate almost any part and feature.
As the probe is moved along a given axis an infrared emitter bounces light off of an etched glass grating. As t he light bounces back, it is read by a collector. The resulting electrical signals are converted to binary code and used to track the position of the axis. The CMM inspection programs run much like CNC part programs, incorporating X, Y, and Z movements. The p rogramming sequence requires that you teach the CMM a series of approach points and measurement points using the remote control joystick with a nominal inspection part fixed to the table.