New impulses for effective rod testing


Bei der Herstellung von Stangen- und Stabprodukten aus Draht treten in der Regel zwangsläufig Außen- und Innenfehler auf, die später zu Reklamationen und teuren Ersatzlieferungen führen können.

During the production of bar and rod products made of wire, external and internal faults are often unavoidable but can lead to complaints and expensive replacement deliveries down the line. Detecting the external faults using an eddy current process is now part of standard, modern rod production. Internal faults, on the other hand, can only be detected using expensive measurement processes. This test is therefore often only carried out in production facilities with particularly high quality requirements (e.g. for aviation). The large investments which have been required up to now for two separate test stations for this purpose are generally not feasible for small and medium-sized companies. The consequence: Internal faults often remain undetected and only come to light later due to complaints.


FIDUS: Absolutely innovative, impressively effective


With FIDUS (fault identification in rods and wires using ultrasound), BFI Betriebstechnik GmbH presents a new, innovative testing system with a wealth of benefits.


Test twice as much with a single probe


FIDUS is the only system in the world to detect both internal and external faults and combines both tests into one device. It therefore does away with costly setup times. The feed rate of the wire/rod can also be significantly faster than with the familiar eddy current / ultrasonic test. A large diameter range can be monitored with a single probe. You don’t need to change or adjust the probe as often. As a result, production times and costs are significantly reduced. For a higher profit in every contract.


Contact-free controls, no coupling media required


Unlike the conventional test, where the ultrasound is very laboriously introduced into the workpiece via coupling media, the contact-free test can be used for virtually any type of metallic material. All this without corroding the workpiece and without the complicated residue-free removal of the coupling medium remains.


Good in principle: EMAT


FIDUS is based on the physical principle of EMAT technology (Electro Magnetic Acoustic Transducer). Here, current pulses form a strong magnetic field which results in elastic deformations in the rod to be tested and is used to generate ultrasonic waves. The ultrasonic waves pass longitudinally through the rod. In fault areas, part of the sound energy is reflected back as an echo. These echoes are transformed back into current pulses within the receiver coils and evaluated to detect internal and external faults.


Longitudinal instead of transverse: for quicker detection


Unlike the conventional methods, FIDUS transmits sound from the probe to the remote rod end using EMAT ultrasound generation. The sound waves are reflected here. If there is an external or internal fault in the rod, part of the sound energy is reflected at the source of the fault. The probe thus registers a small (fault) and a large echo (rod end). Since FIDUS repeatedly penetrates the entire rod volume longitudinally, the faults can be detected significantly more clearly and thus more reliably through a computational superimposition of the signals. In addition, the rods can go through the system at a much higher speed and thus in a shorter time. For significantly more effective production processes.


Product features:


Bei Draht können Fehler mit einer Querschnittsfläche von 0,025% der Profilquerschnittsfläche nachgewiesen werden

Wire/rod parameters:


Testable diameter range: 1 mm < d < 15 mm
Diameter range that can be covered by one probe (example): 2 - 5.5 mm
Profile shape: Round, oval
Speed up to 10 m/s (practically tested – theoretically over 100 m/s)

BFI solution Brochure Start request
The FIDUS system is based on a measurement principle developed by the institute for scientific research, VDEh-Betriebsforschungsinstitut (BFI, Düsseldorf). Production and distribution under DEh-Betriebsforschungsinstitut licence