A coordinate measuring machine, also known as a CMM, is a piece of equipment that measures the geometries of physical objects. CMMs that use a probing system to detect discrete points on the surface of objects.
The first CMM made its appearance in the early 1960s. Originally developed by Ferranti Company in Scotland in the 1950s, this 2-axis CMM used a 3D tracking device with a simple digital readout that displayed XYZ positions. Ferranti used his CMM to measure precision components for his military products. Three-axis models were developed in the late 1960s.
CMMs are most often used to test a part or assembly to determine whether or not it adheres to the original design intent. CMMs are integrated into quality assurance or quality control workflows to verify the dimensions of manufactured components to prevent or resolve quality problems.
The advantages of using CMM over manual dimensional inspections or controls performed with conventional metrology instruments, such as micrometers and height gauges, are: precision, speed and reduced human error.
There are several different types of CMM. CMMs are generally classified based on their structures. Each structure has its advantages and disadvantages. Let's take a look at the different types of CMM in more detail.