What Types of Metrology Systems are Available to Companies?
Applied metrology can be carried out to measure parts and production pieces in a variety of ways. Often, the best solutions lie behind utilising several types of metrology systems, and fortunately, OGP has crafted multi-sensor platforms such as the SmartScope and Vantage that allow you to use these solutions in tandem on one machine.
First, let’s look at the original systems.
Old-school metrology
Despite the superiority of automated metrology equipment, manual equipment still finds its place on many shop floors. Some types of metrology tools are as simple as they come; straight-edge rulers, right-angled squares, protractors, and spirit levels all still see usage, though their accuracy and efficacy depend heavily on the user, and even the most skilled metrologist is going to find themselves only able to work so fast.
Tools like micrometers and calipers have moved on enough that they are typically available with digital displays for easier readouts, but they still require manipulation by hand to use, and can easily be misleading if not finely tuned to their current application.
The new way
Enter the modern era of industry and the automated solutions it has to select from. Multi-sensor metrology technology can take readings in varying ways, and the best offerings from OGP use different sensors simultaneously to get the most accurate readings. So accurate, in fact, that certain readings are precise to within 1 µm.
Tactile
Tactile sensors, also referred to collectively as touch probes, gather information by touching the surface of the object. This is particularly useful for features that are difficult to image or are inaccessible to a video sensor.
Tactile sensors can touch individual points, or they can be set to automatically scan between user-defined start and end points. Feather probes are ultra-light tactile sensors for working with very fine details or delicate materials.
Laser
Laser sensors use high-accuracy focus points for non-contact measuring. Digital Range Sensor laser probes use triangulation to determine surface heights, with exact positional information given to the metrology software at selectable data rates and spacing intervals.
Through-the-lens probes utilise interferometry to measure materials with a wide range of properties from light scattering to translucent with micrometric precision. For transparent and easily deformed surfaces, a Rainbow Probe measures where other sensors can’t. Laser probes can fetch readings accurate to within a micrometre – the average width of a bacterium.
White light
Chromatic white light sensors use a special lens that refracts white light differentially according to its wavelength. The intensity of the reflected light is read by the metrology machine to calculate distance measurements. This is especially useful for highly reflective objects and surfaces that absorb light such as matt black finishes.
White light sensors also excel at measuring microstructures and the thickness of pieces like glass lenses.
Video
High-resolution video allows for fast and repeatable non-contact measurement of a part. With motorised zoom lens and automatically recalibrating optics to adjust for changes in magnification, metrology machines like those of the SNAP range come through for when you need to see a part as it is, up close and personal.
OGP offers a unique aspect to video sensors, with the ability to take the captured images from these advanced video sensors and combine them with proprietary edge detection and autofocus algorithms available exclusively in OGP metrology software packages.
By combining the solutions above – which are just some of the technologies and the forms in which they can be employed in metrology – you can gain a comprehensive, in-depth, detailed report of every nook and cranny of a part, and all within minutes. Turned parts can be profiled using video and white light; blind holes can be measured using lasers or feather probes depending on the depth and angle. There are many types of metrology readily available for any measuring task.
Whatever the challenge, there’s a sensor and a method for it, and OGP UK’s experts can recommend the best equipment for your goals. Get in touch and put us to the test today.