As described in previous newsletters, the focus on the various technological solutions for thickness measurement of flat metal strips is a focal point of the current EMG project and ongoing development activities. The first topic at this point is thickness measurement using the X-ray transmission method.
Thickness measurement with X-ray sources is always used when tough ambient conditions (e.g., in hot mills), very high accuracies (e.g., in foil rolling mills) and/or fast controls (such as for controlling cold rolling stands) are involved. As shown in the image, the X-ray source and detector are arranged on opposite sides of the material to be measured. The non-absorbed part of the X-ray radiation provides the basis for a highly precise thickness measurement, where material-related influences are compensated by the software. The EMG iTiM xray measuring system has been developed to ensure protection of the entire system even when used under the most difficult conditions in hot and cold rolling applications.
In the following table the advantages and limitations of thickness measurement with X-ray radiation are summarised as well as some technical data of the EMG iTiM xray solution.
Advantages | Important to know |
No temperature influence | Handling of X-ray sources requires official approvals |
No surface, dust, fog, vibration influence | Country specific installation and import requirements for X-ray sources |
Low pass-line influence | Alloy compensation required |
Medium spatial resolution | Higher thickness values require higher generator voltages |
Very robust and stable systems | |
High radiation safety (can be shuttered or switched-off) | |
Basic technical data EMG iTiM xray | |
Thickness range | 0.002 – 60.00 mm |
Operational modus | one or more measuring heads stationary / scanning modus for profile measurement |
Measuring gap | up to 2000 mm |
Accuracy (according to IEC 61336) | ± 0.1 % of measurement value |
Integration time | ≥ 1ms (selectable) |
Overview EMG iTiM xray features and technical data
Due to the wide range of X-ray generators, the EMG iTiM xray measuring system can be used in a large thickness range and on different materials. This leads to highly precise measurement results for the thinnest aluminium foil up to 50 mm thick and 1200 °C hot steel sheets. For use in rolling stand controls, a laser-optical speed measurement is integrated into the measuring frame so that the entire measuring technology, including the sensitive parts of the speed measuring device, are protected.
EMG iTiM xray also provides the ideal basis for documenting material characteristics in quality assurance applications in the automotive industry or even in steel and aluminium service centres. A combination with further EMG quality assurance systems, such as roughness measurement, width measurement, etc. is easily possible.
In summary:
With regard to X-ray based measurement techniques, it can be summarised that this method is well established in the hot and cold rolling sector. The EMG iTiM xray gauge can be used over a wide thickness range due to different generator voltages and provides highly accurate measurement results. One or more measuring heads can be applied in a stationary mode or in scanning mode for high-resolution profile measurement. EMG iTiM xray measuring systems are characterised by a high level of durability and robustness, are largely insensitive to external influences, and deliver highly accurate measurement results in very short sample times. This makes these solutions ideally suited for the inline control of rolling mills in the sense of a closed control loop.
Please contact us at any time!
You can find further information about EMG iTiM on our website and you are welcome to contact our international sales and service organisation at any time, which will be happy to assist you with any questions you may have.
Download: Brochure EMG iTiM