We live in a well-measured out world. Practically every aspect of our lives gets measured. We are a metric-centered generation. Most of us are relatively familiar with length, width and height.
There are however those physical objects with more than these three dimensions. Machined parts and other multi-dimensional objects require additional measurements to form a complete picture of their dimensions.
These measurements are performed by a special class of measuring device. It is called a coordinate measuring machine or CMM. Check out these fascinating facts about this most interesting technology.
According to CMM Solutions in the United Kingdom, the first versions of these measuring machines made their initial public appearance at the International Machine Tool Exhibition in Paris in 1959.
It was first brought to market by Ferranti. This is also the company that developed the first commercially viable computer in 1951. With such a surprisingly long history, it is puzzling that CMMs are not more commonly familiar to the public at large. Check it out here.
What is a Coordinate
For this application, a coordinate is simply a point or location within a multi-dimensional object. A coordinate measuring machine is a machine that can access, locate and measure these key points within a shape.
These measurements then create a representation of the image points they locate and measure. A simple example is measurements which are contained in a cube. In short, this machine measures the geometric details of physical objects.
Coordinate Measuring Machines (CMM) Physical Description
These machines come in different sizes and frame setups based on their specific applications. One of the most common is a four-legged frame. The CMM sits on sliders mounted on top of the rails supported by the four legs.
The measuring device is equipped with a probe that swivels to find the key coordinates of the object being measured. This probe is attached to an arm that can extend the measuring probe into and around the different compartments of the object.
They come with multiple probes and styli which are used interchangeably depending upon the object being measured. They are all stored on an accessible rack on the machine.
Coordinate Measuring Explained
To use the four-legged frame model with manual operation, place the object to be measured within the frame of the CMM. Slide the measuring device over the object.
Use the motorized heads and probes to measure the object. Optionally, allow the on-board measuring device do it for you if the machine is so equipped. .
Either an on-board control system or a manual operator of the machine, measures the x, y and z coordinates of the object, depending upon the machine model.
These measurements are then uploaded into a Computer Aided Design (CAD) system with a modeling package to compose the visual image of the object measured.
You can get a quick look at one in action here.
Three Main Parts of These Machines
These CMMs are made up of three main components: the measuring machine, control and probe.
The measuring machine contains the measuring and recording technology. They either have a control system built in, or they have a control system that can be controlled manually by a trained operator.
Each CMM also has a measuring probe that can be fitted with the styli which come with the different measuring arms as part of the measuring technology. All three features differ according to the model and application design.
Variety of Selection
Coordinate Measuring Machines have a wide variety of applications. When shopping for one, buyers should know specifically what they need in terms of features, capabilities and machine size.
Keep in mind details like capacity. This feature refers to the size of the objects the buyer needs the machine to measure. Another important buying detail is measurement speed. A manual machine is slower than one with built-in measurement control.
Other key features are resolution, and is the smallest detail the machine can measure. The length capacity determines how far the probe can extend to get the required measurement. Careful selection of these and other feature options are key considerations for getting the correct coordinate measuring machine that best fits a company’s needs.
The coordinate measuring machine makes critically important and accurate measurements of many of the everyday objects we take for granted. They are used across a wide range of industry.