Research is an investment in the future

All our developments are achieved through the implementation of scientific innovations based on application-oriented research. For each application it is our goal to develop solutions that guarantee improvements in the performance, speed and efficiency of testing systems. As such, we also actively contribute to the determination of international standards and guidelines.

Combined testing for cracks and grinding burns on bearing rings and rolling elements with a single sensor and a sensor array

Contact free, quick, high-resolution and efficient

In addition to the solutions for various tasks requested by industry, testing for cracks and grinding burns on bearing rings and rolling elements is a current issue. These client requirements can be addressed in a semi- and also a fully automated manner. Depending on the testing task, single sensors or sensor arrays can be used.

In the example below, when testing rolling element components, the detection of even tiny cracks and grinding burns is essential. Sensor array technology is used increasingly for these applications, in order to maintain the required cycle time of the automated testing systems.

An 8-fold sensor array is used in the present case to test the inner and the outer ring. Six sensors are arranged in two staggered rows to test the running surfaces. One sensor each is arranged at a right angle (90°) to test the lateral surfaces (rims). The sensor array is controlled accordingly by the ELOTEST PL600 and suitable sensor elements are selected for each test respectively.

8-fold sensor array KDA-129 with six sensor elements arranged in two rows for testing the running surface of bearing rings and two sensor elements each arranged at a 90° angle to the others for testing the run-up rims.

Every sensor is a combined differential / absolute sensor. The absolute coil can be used for both the electronic lift-off / distance compensation and (at the same time) the additional testing for extensive grinding burn.

The sensor array is connected to the testing channel of the ELOTEST PL600 via a fast 8-fold multiplexer.

ELOTEST PL600 is a digital eddy current testing instrument and it is ideally suited for all types of eddy current testing such as testing for cracks, heat treatment, material mix-up and grinding burns.

It is provided with a connection for active sensor arrays with up to 64 sensors per channel. The high multiplex rate allows for testing at very high velocities and thus significantly reduces the test cycles and the throughput time of the testing system. ELOTEST PL600 with its sensor array technology is thus ideally suited for a fast and efficient testing for cracks and grinding burns in automated systems.

C-Scan image of a running surface provided with two 1 mm laser points for simulating grinding burn, scanned with the sensors on the front of the array. Display and processing in the ScanAlyzer.




Source: Rohmann GmbH, internal application report.

EMDC technology – precise test results for all parts

With the EMDC (electromechanical distance compensation) technology developed by us, even the most difficult testing tasks can be solved easily . No matter whether it concerns non-round parts, parts that are difficult to center, parts with complex geometries, or generally parts with concentricity problems: the distance between probe and test product is controlled electromechanically. This ensures a consistently high measuring sensitivity and almost perfect compensation even with large distance changes. In combination with the ELOTEST PL600 you are guaranteed a test system with the highest flexibility.

The Eddy+ testing method – heavy plate hard spot testing from ROHMANN


In the steel production process, increased local hardening can occasionally occur on the surfaces of semi-finished products, which can lead to problems that range from difficulties in further processing to component failure. One of our developements, the Eddy+ method, provides reliable and non-destructive inspections for increased surface hardness, quickly and easily detecting hardness differences. For this purpose, specially developed hardware and software and a special probe are used to perform a partial reversal of magnetization with a bipolar magnetization pulse, while the actual eddy current probe measures the associated permeability change. The advantage of our method is that disturbing interferences for conventional eddy current testing (e.g. by a rolling skin) are eliminated, but still quite high testing speeds of 1m/s can be achieved. This new testing method has also been applied for a patent.

Way-based filters – reliability at every testing speed

Different speeds and fixed filter settings in the test often lead to problems in error detection. This is where our path-based filters can help, as offered by ROHMANN with the ELOTEST PL600, which provides reliable test results even at complete standstill and thus guarantees speed-independent testing with constant signal quality. This means that the material does not have to be tested again in the event of a standstill and the test can be continued immediately.

Electronics are the core of our testing systems

In daily use, the electronics in eddy current testing systems must satisfy extreme demands on precision, dynamics and ruggedness in the measuring sequence between probe and signal evaluation. ROHMANN uses state-of-the-art components to produce sophisticated electronic functional modules, which are built according to exacting specifications on powerful CAD systems, inspected in accordance with our own strict guidelines, and seamlessly documented. The use of digital technology here makes it easier to perform complete simulations of electronic modules and allows an integrated check of functionality, automated alignment and the computer-based calibration of our products.

Software is the life of our testing systems

Today, software can be used to program every level of modern electronics systems. Their programmability is the reason our electronics systems are so powerful and flexible. ROHMANN has a highly qualified team of experienced specialists for all programming tasks. We also have a comprehensive portfolio of programming systems and development tools, ranging from assembler to complex high-level languages, from CAD-based development systems for electronics and mechanics, to tools for graphic-oriented programming of custom solutions for specific applications. With ROHMANN software, testing instruments are more powerful, smaller, and less costly, making it easier to implement customer-specific solutions.

Mechanics are the locomotor system of our testing systems.

From the simplest mechanical guidance tool to automatic inspection mechanics and robot-based handling systems – at ROHMANN, any level of mechanical system can be realized. To achieve the highest accuracy and consistent quality, ROHMANN always uses precise CNC technology to produce its probes and mechanical systems. To ensure that these high standards are met, ROHMANN regularly performs mechanical and electronic calibrations in compliance with national and international standards, and has specifically introduced its own internal calibration system to accomplish this.

Sensor technology is the eyesight of our testing systems.

In the material to be tested sensors register eddy-current signals, so they are the first decisive link in an entire measuring sequence. The measuring sequence can only process that which has first been recorded by the sensor systems. So, sensor technology with excellent “eyesight” is indispensable. All ROHMAN probes are optimized to detect physical effects or defects, but they also meet all requirements related to the material, geometry and complexity of the test specimen’s composition. For this ROHMANN has developed advanced probes, many of which have become the global standard today.

Dillinger manufactures technologically outstanding and versatile heavy plates at the traditional Saar location. References in a wide variety of application areas are available worldwide. Especially for pipeline applications, the HST test procedure developed by ROHMANN supports the precision and consistently high quality of Dillinger products. Dillinger Hütte

Eisenwerk Brühl GmbH specializes in the development and mass production of cast iron engine blocks for the automotive industry. The company is one of the most important suppliers of cast iron ZKG for the passenger car sector. To secure the production process, i.e. for the detection of material defects, hand and line testing devices from ROHMANN are used. Eisenwerk Brühl GmbH

As a subsidiary of the Etihad Aviation Group, the company offers services in the areas of line, light and heavy maintenance. The largest service provider for commercial aircraft in the field of maintenance, repair and operation in the Middle East, uses both the ELOTEST M2 handheld tester and the ELOWHEEL 1000 rim tester (RPT16) for inspecting their aircrafts. Etihad Airways Engineering

Stüken is the world market leader for deep-drawn components, punch and deflection parts of maximum precision and reliably high quality. For automated quality assurance, i.e. for the detection of material and structure defects, Stüken uses line testing equipment, e.g. the ELOTEST PL600 from ROHMANN. Hubert Stüken GmbH & Co. KG

Lufthansa Technik offers a complete service for aircraft technical services, such as maintenance, overhaul and testing of engines and chassis. In addition to the robot-based ELOSCAN test systems, Lufthansa Technik AG also uses sensors and portable test equipment from ROHMANN at several locations in Germany. Lufthansa Technik AG

NKT is a well-established and global supplier of turnkey DC and AC cable systems, providing world-class energy transport with innovative cable solutions. To ensure the quality of its own products, NKT uses the line tester ELOTEST IS500 from ROHMANN. NKT Group GmbH

Siemens Power Generation Services provides worldwide service solutions for gas or steam turbines, generators or wind turbines to increase the efficiency, reliability and operational flexibility of plants. In its global maintenance services, the company uses a.o. the ROHMANN handheld tester ELOTEST M3. Siemens

As a traditional aviation manufacturing and maintenance company, Zeppelin offers professional QM services to the global aviation industry, the automotive industry and mechanical and plant engineering. For the aerospace sector, Zeppelin carries out ZFP training courses using ROHMANN handheld testers Elotest M3, test probes and calibration standards. Zeppelin Systems GmbH

ZF is a leading global technology group in driveline and chassis technology as well as active and passive safety technology. ZF uses a wide range of innovative solutions from ROHMANN for various testing tasks in the field of crack and structural testing. ZF Friedrichshafen AG

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