A Coordinate Measuring Machine (CMM) is a precision measuring instrument that is used to inspect the geometric characteristics of a workpiece, such as its size, shape, and position. It is a type of metrology equipment that uses a probe to touch and measure the surface of the workpiece, and then uses computer software to analyze the data and provide accurate measurements.

The basic components of a CMM include a measuring head that holds the probe, a table that supports the workpiece, and a control system that processes the measurement data. The measuring head is usually mounted on a bridge-like structure that can be moved in three directions: X, Y, and Z. These three linear axes, allow the measuring head to move and touch the workpiece in order to measure the geometric characteristics.

The probe, which is the sensing element of the machine, can vary depending on the application and the complexity of the part. It can be a simple stylus that makes point-to-point measurements, or it can be a touch-probe that can measure complex geometries by scanning the surface of the part.

CMM measuring machines can be classified into two main types: contact and non-contact measurement. Contact measurement is when the probe touches the workpiece, while non-contact measurement uses lasers, cameras or other sensors to acquire the measurement data without touching the workpiece.

CMM measuring machines are used in many different industries such as aerospace, automotive, and precision manufacturing to ensure that parts are manufactured within the acceptable tolerance levels and to improve the quality of the final product. They require highly skilled operator, proper calibration and maintenance to produce accurate and precise measurements.