ABCs of Multisensor Measurement - Optical Gaging Products - #1

BY WILLIAM VERWYS

A video measurement of a cast metal part is illuminated by an LED ringlight Photo: Optical Gaging Products

A star touch probe measures a cast metal part on a multisensor measurement machine. Photo: Optical Gaging Products

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re and more companies are offering ultisensor measurement systems, yet ost of the available information

Sensor technologies can be grouped in two major categories—contact and noncontact. Contact sensors are those that apply any pressure to a part to obtain a measurement. Coordinate measuring machine (CMM) touch probes are the most common type of contact sensors.

Noncontact sensors do not require physical contact with the part. There is a broad range of noncontact sensor technologies that use cam­eras for optical imaging. Laser scanners use optics and detectors to capture laser light reflected from a surface. New microprobing technologies use resonance technology or spec­tral analysis of light related to the distance between the probe and the surface. Any combi­nation of contact and noncontact sensors on a single measurement machine makes it a multi­sensor measurement machine.

The three sensors commonly referred to are touch probe, video and laser. Touch probe typically refers to a touch-trigger probe such as those commonly found on a CMM. Video refers to video measurement, as with dedicated measurement machines with lighting, optics and software for measurement of video images of a part. Laser means a light source to illumi-

about such systems is with regard to sensor tech­nologies. Although it is helpful to know how dif­ferent sensors work, it is more important is know how to make use of more than one sensor to improve manufacturing productivity.

♦ All measurement systems use at least one type of sensor technology.

♦ The sensor collects data points from a part to obtain a measurement.

♦ Data points can be collected by numerous sensor technologies such as a touch probe, video, laser and microprobes.

There may be some confusion about what a multisensor measurement system actually is. All measurement systems use at least one type of sensor technology. The sensor collects data points from a part to obtain a measurement. It is the probe, or detector, that "senses" the part.