Over the last two decades, electromagnetic methods passed through an extensive technical development up to a degree where - in the frame of nondestructive testing technologies - they have to be labeled as "key technologies".

In matters of the upcoming remodeling of industrial high-tech sectors towards "Industrie 4.0" concepts, the embedding of electromagnetic sensors and sensor systems offers forward-looking development potential for the comprehensive digitization and process control of industrial production and processing systems.

Moreover, last decade's developments in automotive industry away from internal combustion engines to electromobility are to be kept in mind. While the inspection of ferromagnetic materials is a matter of course in inspection technology, in the near future development, examination and control of technical magnetic systems will gain considerable economic importance, too.

3D SmartInspect: Intelligent Inspection Monitoring and Documentation by Optical Tracking System for Ultrasound and Eddy Current Inspection

3D SmartInspect – a Fraunhofer IZFP tool for the digital NDT world: Augmented Reality System as a support for the manual inspection of components or large surfaces
© Fraunhofer IZFP / Uwe Bellhäuser
3D SmartInspect – a Fraunhofer IZFP tool for the digital NDT world: Augmented Reality System as a support for the manual inspection of components or large surfaces

In the case of the widely used manual inspection, the quality of the inspection depends strongly on the personnel and the environmental conditions; this fact concerns the inspection of small com­ponents in production as well as the maintenance inspections of large industrial structures. The ­adequate interpretation of the measured values and the thorough coverage of the inspection area require a high degree of personal expertise. In addition, companies face considerable challenges with regard to documen­tation. Often, inspection reports are drawn up by hand and any peculiar observations are marked on the components themselves. A digital link between the specimen and the documentation is not established. If inspections take several hours or days, errors and incomplete documentation can occur, leading to negative consequences for subsequent processes.

To solve this topic, Fraunhofer IZFP has developed the optical tracking system “3D SmartInspect“, an assistance system for manual inspections based on cognitive signal evaluation.

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Sensor System to Detect Cracks and Neckings in Formed Sheets

Tailored Blanks inspection with Fraunhofer IZFP´s EMAT sensor
© Fraunhofer IZFP
Tailored Blanks inspection with Fraunhofer IZFP´s EMAT sensor

Requirements on components and processes in the sheet metal forming sector are steadily rising. This applies in particular to the automotive industry as the largest manufacturer and buyer of formed sheet metal parts. Due to lightweight construction concepts, many forming processes are increasingly being pushed to their limits. Because of growing processing complexity, high forming degrees with ever smaller sheet thicknesses, batch fluctuations of the materials as well as uncertainties in the tool / machine system, it is unavoidable that these process limits are sporadically exceeded.

As a consequence of such influencing factors, forming-related component defects that are difficult to identify cannot be avoided completely. This includes cracked areas (cracks) in the sheet, but also local thinnings of the sheet thickness (neckings). While gaping cracks above a certain size can be reliably detected with optical methods, so far there was no method for the reliable detection of closed or small cracks and in particular of neckings.

A comparative study showed that the so-called EMAT inspection technique (electromagnetic acoustic transducer) is the most appropriate method for the production-integrated detection of cracks and neckings in sheet metal components. Ultrasonic probes based on EMAT can be used dry, i.e. without coupling agents and generally without contact.

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Broadband Eddy Current Inspection Electronics for Multi-Channel and Multi-Frequency Applications

inspECT-PRO mit OPC UA Interface
© Fraunhofer IZFP / Uwe Bellhäuser
inspECT-PRO broadband eddy current electronics with OPC UA Interface

Inspection of electrically weakly conductive materials such as carbon fibers (CFRP), detection of surface and near-surface defects, layer thickness determination, mix-up inspection, material characterization, OPC UA interface


  • 2 parallel analogue hardware channels with the ability to generate different signals such as sinus/rectangle signal shapes as well as arbitrary signal forms
  • Single- and multi-frequency operation with up to 32 inspection frequencies from 10 Hz to 112.5 MHz per hardware channel
  • Multi-sensor operation with up to 32 sensors per hardware channel, realized by an external multiplexer for flexible positioning of the sensor-near electronics as well as far-reaching inspection distances
  • Assembly of multi-channel systems by cascades of multiple inspECT-PRO electronics, enabled by the modular concept and adapted to the customer requirements
  • High sampling rate per channel: 125,000 samples/s (single-frequency mode), up to 1200 samples/s (multiplex mode) at 32 frequencies and/or 32 sensors; customized applications possible
  • Integrated 3-axis coordinate and CTP interface (Cycle Trigger Pulse)
  • Realtime inputs and outputs as well as OPC UA interface for data and process control
  • Realtime signal processing and data assessment already on the inspECT-PRO electronics
  • High-performance software for a great variety of inspection tasks with integrated regression analysis and classification algorithm



inspECT – DeepFlawDetector

© Fraunhofer IZFP / Uwe Bellhäuser

Rapid, large-scale testing for deep-seated flaws such a cracks or corrosion under metal or non-metal coverings using GMR line arrays


  • Rapid testing without a need to use means of coupling
  • Constant frequency-independent testing sensitivity with high local resolution
  • Rapid adaptation to different test situations (by transferring the GMR sensors into the existing technical hardware)
  • Sensor systems with 8 or 16 GMR sensors are available and/or individually configurable
  • Real-time test data display in the C-scan currently available with simplified indicator interpretation
  • Robust, mobile industrial laptop system that can also be connected to conventional eddy current sensors


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Portable Magnetic Flux Leakage Inspection System for ­Detecting Corrosion Damage in Prestressed Concrete Poles

© BauConsulting Dr. Walther

Magnetic flux leakage inspection

Intuitive representation of the location and condition of ferromagnetic prestressing steel

Specifically designed for portable use

Easily adapted to different concrete pole diameters

Less effort compared to alternative inspection methods such as X-ray

Minimal risk of additional pole damage

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3MA-X8: Fast Materials Characterization

© Fraunhofer IZFP
3MA-X8: Three channels, assortment of sensors, plus control and evaluation PC

Determination of hardness, case depth, tensile strength, yield strength, breaking elongation, residual and load stresses

Test for mixed-up components

Determination of dross in cast materials

Area scans with up to 8 sensors and concurrent detection of local material property deviations

Inspection of assemblies and components parallel at several positions

In-line real-time measurements in production processes

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inspECT: Multi-Channel Multifrequency Eddy Current Inspection Electronics

© Fraunhofer IZFP

Mobile eddy current testing system realized inside a rugged industrial notebook with IP65 protection class

OEM kit: Comprising inspECT board, backplane, power supply, coordinate ­interface and multi­plexer for integration in customer systems

Integration of any customer-adapted inspection electronics into customer systems

Single or multifrequency operation with up to 16 testing frequencies from 100 Hz up to 10 MHz

High-performance hardware enables signal processing in real-time already on the ­inspECT board

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GMR Sensors: Optimization of the Layer Properties

© Fraunhofer IZFP

Eddy Current Impedance Analysis

Eddy Current Scans up to Microscopy

Conductivity, Permeability, Permittivity

Layer Thickness, Material and Condition

Sensor Systems: Automatic Configuration and Planning Admissions

Machine-Material-Interaction: 3MA system integrated in the production line in order to monitor mechanical-technological material properties of steel strip during manufacturing

Robot-assisted inline-monitoring system for hardened and tempered steel strip

Continuously self-adjusting positioning of the sensor by robots based on sensor-own signal generation and signal processing

Continuous determination of hardness and residual stresses within the steel strip

Permanent readjustment of the process through independent extraction of relevant information by means of “cognitive sensor systems“

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Hardness, Case Depth, Yield Strength, Tensile Strength

Nondestructive Inspection pf Presshardened Body Parts using 3MA

Nondestructive Evaluation of Hardness and Residual Stress Depth Profiles of Valve Springs by 3MA

Clinching: Offline and Online Measurement of the Wall Thickness in Clinched Joints

© Fraunhofer IZFP
Prototype system for offline determination of base thickness in clinched joints

For a fast quality monitoring of clinched joints, the eddy current method was refined

Combination of several eddy current frequencies

Disturbances such as sensor lifting from the surface or changes in conductivity and permeability can be distinguished from the objective criterion “base thickness“

Calibration needed

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Self-Sufficient Platform for Permanent Condition Monitoring of Infrastructure Constructions

© Katharina Wieland Müller- Pixelio

Modular, energy self-sufficient board providing eddy current inspection, inclination measurement, magnetic flux leakage inspec­tion, ultrasonic inspection, etc. and recording all sampled data over long periods of time while dissipating extremely low amounts of energy

Self-sufficient and eco-friendly power supply by integrated photovoltaic cell

Maintenance-free long-term operation

Supersensitive defect detection

Telemetric data recovery by radio-controlled interface

Low costs per unit

Unique combination of Fraunhofer IZFP‘s proven nondestructive sensor technology

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3MA-Based Valve Spring Scanner: Nondestructive Evaluation of Hardness and Residual Stress Depth Profiles

© Fraunhofer IZFP / Uwe Bellhäuser
Valve Spring Scanner

Concurrent determination of various relevant quality characteristics of a material (e.g. hardness, residual stresses in different measuring depths)

No destruction of the specimen

Integration in fully automated testing systems

Calibration needed

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