The manufacturing tolerances of modern products and the aim for high quality require ability to make precise measurement of dimensional measurands on small artefacts of complicated shapes. The use of vision measuring machines and machine vision is well established in non-contact high-precision measurement.
VTT MIKES have a Mitutoyo Quickvision Hyper QV-350 vision measuring machine (optical CMM or video measuring machine) that is equipped with a CCD camera as well as with a contact probe. In non-contact optical measurements, the machine takes advantage of the measurement point location detected by the CCD camera and location information from the precise scales attached to mechanical guides. The device measures the height coordinate by focussing method.
The machine is computer-controlled and measurements are fully automated. The machine is capable to measure length, diameter, angle, straightness, flatness, parallelism, and roundness. The machine is especially suitable for measurements of circuit boards, thin-walled fragile plastic and metallic artefacts, and other artefacts that are inconvenient or impossible to measure with techniques using contact probes. The artefact under study can be illuminated with ring, coaxial or stage light. There are four controllable segments in the ring light and its height can be adjusted.
VTT MIKES provides precise optical and contact dimensional measurements tailored according to customers’ needs. Depending on the work order, a calibration certificate or a field log is provided.
Main properties of the optical CMM.
|Measuring volume||350 mm x 350 mm x 150 mm|
|Size of the bench||490 mm x 550 mm|
|Maximum workpiece mass||15 kg|
|Lowest measurement uncertainty (k=2), optical mode *||U1XY = (0.8 + 2 L/1000) µm **
U2XY = (1.4 + 3 L/1000) µm **
U1Z = (3 + 2 L/1000) µm **
|Lowest measurement uncertainty (k=2), contact mode||U1XY = (1.8 + 2 L/1000) µm|
|Maximum speed (rapid travel)||100 mm/s|
|Maximum acceleration||490 mm/s2|
|** The repeatability of the device allows more accurate measurements if necessary. With a well-|
defined target and by substitution measurement, less than 0.5 µm uncertainty can be achieved.
* L is length in millimetres. U1 is uncertainty along one axis, U2 along two axes.
- Ville Byman, Research Scientist, tel. 050 386 9327, email ville.byman(at)vtt.fi
- Björn Hemming, Senior Research Scientist, tel. 040 773 5744, email bjorn.hemming(at)vtt.fi
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