METIS: Diameter, distance and clearance measurements at high frequency

For the non-contact measurement of large diameters – for example of pipeline pipes – LAP uses two sensor-receiver pairs. This arrangement enables diameters of up to 1,500 mm to be measured with accuracies in the µm range.

In the “big diameter arrangement” laser micrometers of the new METIS line of LAP products measure diameters and distances with a resolution down to 5 nm, achieving repetition accuracies between +/- 2 and +/- 8 µm.

The new METIS laser micrometers are used, for example, for measuring diameters, positions, distances or clearances of turned parts, pipes, cables or tubings. As part of inline production control they monitor the entire manufacturing process and document the correct dimensions of the produced parts.

LAP designed the new sensors for application in industrial production environments. A distinguishing feature is that even at very high measuring rates they provide measurements of utmost precision. Thanks to the measuring frequency of 1,600 Hz precise measurements of fast moving objects do not pose a problem.

If several systems are arranged in different axes, they can also capture the roundness or ovality of the work pieces. Additionally, METIS systems are used for measuring the position of objects within the field of measurement or the clearance between objects.
As several measurements can be linked, the systems are capable of capturing diameters, clearances and distances of several objects or the position of several objects all at the same time. METIS is designed to simultaneously handle up to ten edges located within the field of measurement.

The METIS signal processors process the measured values while masking out phenomena like the occurrence of diffraction at object edges or reflections on shiny surfaces. They also control the communication with the process control system.
The measuring field of the smallest model, METIS-45, covers 45 mm x 45 mm at a nominal distance of 300 mm between the transmitter and the receiver, whereas the largest system, METIS-180, has a measuring field of 180 mm x 180 mm and a transmitter-receiver distance of 800 mm.

METIS sensors use the scanning principle: A laser beam scans the measuring field at a frequency of up to 1,600 per second. The object to be measured casts a shadow, when it is hit by the “light curtain”. From the duration of the shadowing an integrated signal processor computes the diameters and clearances. The laser power is less than 1 mW. Therefore the system is classified as a class 2 laser product, i.e. the eyes are safely protected by the eye lid reflex and other defensive reactions.

Whitepaper-Download (449 KB)