Assistance system enhances quality of strip leveling

With GEORG smartleveling, GEORG introduces an assistance system for high-performance strip leveling machines suitable for new line installations, retrofitting projects and the integration of new leveling machines into existing line environments. The system is designed for steel and aluminum strip of a wide range of widths and thicknesses and products that have to comply with very exacting flatness and surface quality requirements.

A key innovative feature of the system is that it measures the flatness of the cut-to-length sheets – i.e. the final products – after the strip cutting process. Thus the flatness data measured of the final products are not influenced by any production-related cross-effects so that they can be used and further processed within the internal production system.

The demand for high-performance levelers designed for the processing of wide strips and sheets that have to comply with highly exacting flatness and surface quality requirements is constantly growing. Examples of such products are exposed bodyshell parts for the automotive and aviation industries, components for tanks, and visible construction elements such as cladding systems for ceilings and façades. Additionally, the variety of materials processed is becoming increasingly greater, as well as the need to ensure complete and consistent documentation of the products supplied. Process automation is a further important aspect, last but not least against the backdrop of the growing shortage of qualified labor. These challenges were reason for GEORG to develop an entirely new approach to optimizing the leveling process and the way it can be controlled.

Leveling is a process designed to enhance the quality of finished sheets in terms of flatness and minimized residual stress – criteria that are essential for the successful further processing of the material. So far, flatness used to be assessed manually by the operator or – if at all – by an optical system arranged after the leveler, but in any case before the strip is cut to length. Due to the overlapping effects of the back-tension acting on the strip downstream of the leveling machine and the influence of the cutting process, the final product may have different flatness properties than the strip when it runs out of the leveler.

GEORG smartleveling

This gave rise to the idea to shift strip flatness measurement to a position downstream of the cutting process and use the measured data as input for optimizing the leveling process. GEORG smartleveling measures the flatness of the final product on the runout roller table, ruling out the possibility of the strip back-tension falsifying the results. The assistance system visualizes the measured values, analyzes them and provides the operator with recommendations for adapting the settings of the leveling machines, if necessary. It is also possible to use the system in an automatic mode to optimize the parameters.

This gave rise to the idea to shift strip flatness measurement to a position downstream of the cutting process and use the measured data as input for optimizing the leveling process. GEORG smartleveling measures the flatness of the final product on the runout roller table, ruling out the possibility of the strip back-tension falsifying the results. The assistance system visualizes the measured values, analyzes them and provides the operator with recommendations for adapting the settings of the leveling machines, if necessary. It is also possible to use the system in an automatic mode to optimize the parameters.

Additionally, suppliers can provide consistent documentation of the final products delivered to their customers. The measured data are also very useful for quality assurance and the traceability of production.

Advanced Leveling – The technology in detail

The software of the new assistance system uses the data provided by an optical – hence non-contact – measuring system arranged at the runout of the cut-to-length line. To measure the elevation of the individual surface points, laser lines are projected onto the sheets when they pass the measuring head on the runout roller table, where they are not subjected to any back-tension. In order to compensate the changing position of the sheet, the system uses dual lines. This eliminates any interfering effects caused, for example, by vibration, and enables the system to measure the height profile with a precision better than 0.5 mm.

The flatness of the produced sheets is graphically displayed in real time on the operator’s screen together with information relevant for the leveling process. The visualization makes it possible for the operators to quickly and intuitively assess the quality of the sheets produced. As also the data of several previously produced sheets are shown, decisions can be instantly made – on the basis of data measured after the leveling process. The system compiles the data of all the sheets produced from each individual coil in the quality report and stores it in a database.

Smart automation

The flatness data are not only visualized, but also automatically analyzed. Based on this, the smartleveling software continuously determines optimized parameters for the leveling machine. The parameters are displayed as recommendations for the operators to decide whether the current process should be adapted. If run in automatic mode, the program adapts the process parameters of the leveler fully automatically. In this case, the consistent use of the data ensures precisely controlled processes and products of consistently high quality while increasing the overall productivity of the line. Additionally, this approach minimizes the loading and stress acting on the machine, reduces energy use and increases the lifetime of the components.

All data concerning the flatness of the sheets are archived complete with the related production parameters. They remain available for later retrieval so that they can be used at any time in the future for leveling parameter optimization. Such a database of production parameters is extremely helpful, especially in steel service centers that handle comprehensive product ranges and complex materials, as it makes it possible to also call up leveling data relating to coils processed some time ago.

The operators generally already achieve very good leveling results with the basic machine settings calculated by GEORG for the respective materials. The basic settings are part of the supply scope of smartleveling, as well as the recipe database that can be filled with data by the customers themselves.

Application specialists can access the data stored in the database offline by means of the smartleveling analysis tool. In this way, they can analyze how specific sheets were produced and provide support to further optimize the leveling process. The data can also be used for training purposes, for example, to familiarize operators new on the job with the production line.

Especially, wide and thin strips require high-performance machines that ensure outstanding operating precision and backlash-free, exactly repeatable positioning of the leveling rolls. Here, GEORG can build on decades-long expertise in the construction of cut-to-length lines with integrated GEORG levelers that its customers use for the processing of a wide and varied range of products. All machines are characterized by excellent precision, repeatability, availability and longevity, features that have always been synonymous with GEORG.

The GEORG high-performance levelers are available in modular design. The dimension range – for example, for exposed airplane parts – includes sheets up to 3,200 mm wide.

An integral component of all GEORG levelers is the tried-and-tested cartridge change system that has proved highly effective and reliable in numerous cut-to-length lines. This system ensures that cartridges of the same type always provide exactly the same results, even after roll regrinding or maintenance. All GEORG change cartridges are equipped with a digital coding that allows them to be reliably identified for the parameterization of the machines and for service and maintenance activities. In this way, the control system of the levelers can compensate fully automatically any regrinding effects, ensuring the use of exactly the same process parameters.

The change cartridges are the core components of GEORG leveling machines. They are high-precision tools designed to withstand very high mechanical stresses during operation. Their design and manufacturing requires profound and detailed knowledge. The same holds true for their maintenance. Therefore, GEORG offers line operators a service package that includes the service of having the change cartridges shipped to the GEORG workshop in Kreuztal at regular intervals for maintenance. This ensures that the levelers always operate with the same high precision.

Additionally, GEORG provides training courses both at its facilities in Kreuztal and at its customers’ sites. The courses comprise theoretical knowledge and hands-on training, including the setting up and adjustment of the machine parameters or the leveling of individual sheets.

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