Width measuring systems are therefore used multiple times in all process and further processing stages of flat steel and aluminium or other metals.
At EMG Automation GmbH, the interested user will find two technologically different solutions, which both have their application-specific features.
The optoelectronic strip width measurement EMG BREIMO is the first of these
EMG BREIMO is EMG's traditional non-contact, optical strip width measurement of metal strips in continuous running processes. It consists of a measuring frame with two strip edge positioning devices (EMG EVK), the associated light transmitters (EMG LLS) and a common linear stroke transducer.
The strip edge is detected by the aforementioned motorised edge positioning device, which is equipped with high-frequency (HF) alternating light detectors that are immune to ambient light.
If a lateral displacement of the strip edge occurs due to changes in width or due to the strip's path, this displacement is detected by the photoelectric sensors. The higher-level control electronics then control a DC motor for moving the light barriers or the actuator (servo valve or electro-servo cylinder) of the control loop in such a way that the strip edge always covers exactly half the sensing range of the measuring light barrier.
The system offers high and reliable measuring accuracy (± 0.2 mm, in the high-precision version), insensitivity to height fluctuations of the strip, high operational reliability and ease of use, short commissioning times (minimum installation space), active dirt compensation through reference measuring principle when used in harsh environments (e.g. pickling, cold rolling mill), ambient light immunity through the use of HF alternating light and a remarkably large distance between sensor and light source of up to 4 m!
Further information in the brochure: EMG sensor technology - the basis for an optimum strip guiding system.
The second important width measurement system in the EMG portfolio is the CMOS camera-based EMG iCAM®
The EMG iCAM® system consists of an LED infrared emitter unit below the metal strip and a camera line of CMOS matrix cameras as receiver unit, which is scalable over the strip width in 250 mm steps. Today, strip widths between 1000 and 2250 mm can be realised as standard. Strip widths deviating from this can be discussed on request.
In addition to the precise determination of the strip width, this solution also allows online strip width measurement after slitting shears. Due to the transmission light measurement method, holes and edge cracks can also be detected and evaluated according to severity. These functionalities can also be retrofitted at a later date by means of a corresponding software upgrade.
All in all, the user gets a precise and non-contact measuring method for online measurement of the strip width with additional optional evaluation options for slit strip width measurement as well as hole and edge crack detection. This system also requires very little installation space and is also very easy to maintain, as moving parts have been completely dispensed with.
You can find out more about EMG iCAM® on our website and in the product brochure!
CONCLUSIONS:
EMG offers the right and proven width measurement solution for every process stage in cold strip production (incl. pickling) as well as for finishing stages, adjusting and use in steel and aluminium service centres.