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Multi Sensor Measurement on the CMM

When one is just not enough!

All is right with the world: the CMM is merrily beeping away inspecting parts to its heart's content. What could be wrong with this? This is the perfect device for measuring everything, or is it? The CMM itself is basically a three axis, high accuracy positioning device. What transforms this mechanical entity into a measuring machine is software and probing.

Touch Probing vs. Multi Sensor Probing

Touch probing provides the coordinate measuring machine user with precision and flexibility but, unfortunately, it doesn't do everything well. In fact, with a wide variety of components presented to coordinate measuring machines today, the touch probe system is at best only 50% effective when compared to other methods of sensing.With the advent of quick-change adapters on robotic heads, it's now possible to utilize several sensor configurations on a single coordinate measuring machine. Furthermore, the changeovers between the different sensor systems are written into the software so can therefore run unattended.

Laser Scanners

For soft bodied parts that can be deformed by a touch probe, sheet metal parts, and other inspection applications where throughput and speed of measurement are important, laser technology is an excellent addition to your CMM and a sound investment. Laser probes are best employed in situations where you need to repeatedly inspect similar parts, or where you need to combine free-form surface inspection with feature scanning. These specialized, non-contact probes can often be utilized in conjunction with tactile probing thereby producing optimum results through the use of the right combination of sensors.Because of their high rate of data collection, laser scanners can create solid models from the surface profiles making the laser scanner ideal for reverse engineering, product development and rapid prototyping applications.  These sensors are also extremely valuable when comparing actual data to nominal data. A graphical analysis, illustrated in different colours, can be displayed on 3 dimensional CAD models showing the actual data overlaid on the nominal data. This visual representation allows quick decisions to be made on the shop floor without the requirement of analyzing numerical data. Speed is the greatest asset of the laser probe; considering that this type of device gathers as much as 20,000 data points a second, it's not hard to imagine why.

Vision Probes

Most vision probes feature ultrahigh accuracy CCD camera systems or will occasionally use a laser locator. Upgrade packages also feature enhanced lighting packages allowing the system to create contrast for better edge definition. Applications for vision probes include any part with densely populated features. They are ideal for electronic and medical devices; precision components with micro holes are also easily measured. Basically, anywhere the touch probe cannot go, the vision system can and with extremely accurate results. Once more, vision probes may be mounted within the measuring machine’s change rack and interchanged when required for the conventional tactile probe.

Multi Sensor CMMs

Not only do you have the option of adding additional sensors to your coordinate measuring machine, but there are now multi sensor machines available on the market. These systems come fully equipped with the three basic sensor technologies (tactile, laser and vision). These machines have some distinct advantages. For example, all the sensors are integrated so only one software package is required to drive the entire suite of probes. Generally one fixture or setup covers the entire range of measurement requirements, saving time and additional expenditure for fixtures. The flexibility to measure all features with the optimum probing technology provides better accuracy, increased repeatability and trustworthy measurements.


Multisensory technology can breathe new life into your existing coordinate measuring machine and greatly expand your measurement and inspection capabilities. In many instances, adding new sensory technology like a laser scanning probe, for example, will transform your inspection device into a research and development tool. In fact, that old coordinate measuring machine of yours just might be reborn in a different role.


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