ISRA VISION

Real, simultaneous 2D and 3D surface inspection

The optical, two dimensional (2D) inspection of (rolled) steel surfaces is state of the art and well established today. However, during continuous casting of steel slabs, the application of 2D inspection is very limited due to the heavy material structure at the hot surfaces. Though, defect detection and depth is critical in grading the cast slab. Defect size and depth plays a crucial part for the decision if a slab is released for the hot strip or plate mill, or if it is sent to grinding or rejected.

In contrast to conventional 2D inspection, inspection of the cast slab surface by laser triangulation (3D) inspection offers a fast and reliable detection and classification of surface defects, including depth information of each defect, even during or right after continuous casting. Beside the inspection of four slab sides for defects, the 3D inspection system also generates a complete 3D scan of the slab geometry which opens up the possibility to measure thickness, width and length of the slab as well as it can be assessed for geometrical flaws like ski, camber or the shape of the side faces.

Together with the information about the steel making and casting process this allows blocking and reassigning slabs in the earliest production stages. In combination with the ISRA Parsytec Surface Quality Management System (SQMS) not only a root cause analysis becomes possible but also a simulation or forecast of reachable end product quality.

Extreme low contrast defect detection in cold rolling mills

Roll marks are a big issue for every steel strip producer. They are usually induced by a defective work roll of (cold) rolling or temper mills. With every revolution, the damaged work roll prints a small mark into the strip surface, creating a periodically occurring surface defect.

In tandem mills, the roll mark is usually elongated and over-rolled by subsequent roll stands. This leaves the defect with a very low visual footprint so that it is not detectable by standard surface inspection systems nor by a human inspector.

For exposed steel grades, the detection of roll marks is crucial as those defects will leave a very visual aspect after coating operations like e.g. galvanizing. It is an essential to identify this type of defect during rolling operation as soon as possible in order to avoid production of tons of material that turn out defective at a later processing stage.

A new approach for detection of extreme low contrast periodic defects lays in increasing the defect signal contrast by overlaying images of numerous roll revolutions.

However, current systems using this approach usually have the disadvantage of long processing times or limited inspection time for each coil.

ISRA Parsytec’s approach uses hardware signals of each work roll for reliable image overlaying. This has the advantage of real-time availability of inspection results and a 100 % surface inspection of the entire coil. Additionally, well proven algorithms allow for high contrast defect detection and secure defect classification.

A new compact all-in-one Heavy Duty Sensor Housing protects the sensor in harsh conditions. Sensor and illumination are protected from moisture, oil and dirt and – in addition – an active air flow is generated inside the housing to remove vapors and mist from the inspection area.

Surface Quality Management System

The quality of the product is one of the most important control and steering factors in modern metals industry.

Customers’ specifications and expectations regarding each single order have to be met. With ISRA Parsytec’s (Surface Quality Management System) and the company’s deep industry knowledge and experience, the software is able to derive objective decisions out of the huge amount of collected data. With EPROMI live, steel producers are continuously informed on machinery status via live surveillance of measures and gain the ability to react immediately on upcoming problems.

The system monitoring provides an accurate accumulation and combination of surface inspection system relevant measure data in one central database with

• Live information gathering from worldwide production equipment via standard interfaces and interlink quality data and process information
• Extraction of KPIs for quality and production
• Online visualization of sensor and quality data with predefined rule sets via Condition Monitoring and KPI Monitoring
• Highest system availability with reporting and alarming on KPIs for hardware, defect detection, classification and trends

A perfectly working surface inspection is a precondition for a reliable quality decision. This task will be secured by the EPROMI live.

The Surface Quality Management System SQMS is a business solution especially designed to face this challenge in the metals industry.

The software ties together collected surface data from the whole process, since quality management is a level-crossing function – from order inquiry and order design to planning and product execution, from casting until the last finishing line.

In order to efficiently support line managers, SQMS is specialized on the surface quality, and defines the detailed customer specific quality corridors for each production step. Thereby, for example, a coil for a certain automotive manufacturer passes through the line while being inspected continuously following the precise specifications that have been defined. Those may contain, for example, quality grades from premium to standard to basic. The system enables a quality simulation of each processing steps in the pre-defined corridors in order to avoid any unnecessary added value process or can be re-rooted to other processing lines where the end quality is lower.

EXPERT5i are software modules helping to answer every day’s quality related questions like:

• Does the product quality meet the customer’s quality rules? If not, could quality rules of another customer be fulfilled instead, so that the product can still be sold with a high-level price?
• Can this coil be shipped? If not, how can it be repaired or further processed to reach saleable status?
• What is the root cause for the quality problem?

Many solutions are hidden in the inspection and production data

The EXPERT5i  software modules are the extended arm of plant management, taking action down to the plant floor. With this system you can make use of the inspection and process data being continuously collected at the line. By bringing together all available information, valuable correlations are revealed, which unleash huge potential in managing quality and production efficiency.

The solution quickly helps to find the right answers for many questions concerning yield and process optimization.

Secure highest quality standards

Achieve the goal of a zero-defect production. EXPERT5i  software modules enable you to react immediately to surface defects and other quality deviations. Operators receive early warnings of even approaching problems and can react immediately to secure the highest quality standards continuously. By using the system each process step can be controlled and analyzed, and quality finally becomes plannable.

All information is utilized

To make decisions, the EXPERT5i software modules are able to access all available production-relevant data of the product (surface, thickness, width, flatness, etc.).

The software modules analyze and weigh all of this information according to particular criteria and generate knowledge-based suggestions for the decision makers.

Quick, easy and correct economic decisions

The EXPERT5i software modules are currently available for all of the different tasks along the various production lines.

Any user can implement the software modules, which are suited best to provide the optimum solution for the current application. Steel producers can therefore rely on a state-of-the-art software tool to continually improve their quality management.

In combining selected or all EXPERT5i software modules, the potential for increased productivity is reached: quality becomes plannable, processes and production are systematically optimized.

High-end surface inspection along the entire production chain

Evaluating surface inspection results in one step of the production, e.g. after casting or hot rolling, offers the potential to improve the complete production chain.

Surface defects may be a result of suboptimal process parameters during the rolling process itself or may be caused by process faults or wrong parameters in steel making or casting. Moreover, information about the defect position offers the opportunity for an optimized process in the next production step, e.g. optimizing the pickling speed based on scale detected at the hot mill. Wherefore information will be forwarded to previous and next production steps.

Unique multi-stage classification of SURFACE MASTER reaches new dimensions in performance, classification rates, speed, and set-up time

Fastest tuning, easiest intuitive operating, highest, most efficient classification, ending up in highest inspection performance rates – we made it our business to create a classifier technology with these requirements. Save time and money, and avoid wasting time with other classification tools.

The advanced multi-stage classification technology as one of the core modules of SURFACE MASTER provides excellence in defect recognition which goes beyond inspection.

This fast, accurate, flexible classifier innovation, is combined with a learning classifier for line specific defects and the Instant ClassifierTM pre-set classification for standard applications resulting in classification performance better than 98 %:

• Set-up, commissioning and tuning designed for operators not scientists – easy to understand and to operate
• Integrated, intelligent and intuitive tools to manage image defect collections and classifiers – simple to utilize, highly reliable
• Classifier tuning without influence on running production including extensive check of tuning results for risk free switch from test to active classifier

Constant Pass-Line CPD distance technology is an add-on to the SURFACE MASTER that allows inspection at the coiler, often the only available inspection position. The sensor maintains a constant distance to the inspected surface during the entire winding or unwinding process. This is the only way to ensure reliable inspection with a changing diameter of the coil.

A new compact all-in-one Heavy Duty Sensor Housing protects the sensor in harsh conditions. Sensor and illumination are protected from moisture, oil and dirt and – in addition – an active air flow is generated inside the housing to remove vapors and mist from the inspection area.

The result is a flawless image quality, maximum protection and a long service life for the solution – without being affected by the production environment.