To guarantee a defect-free compound tube, the intermediate metal layer of aluminum or stainless steel is inspected for holes or cracks. Usually, the weld seam of the internal tube presents a weak spot and is tested using a segment coil before the outer plastic layer is extruded over the metal.
The eddy current signals are transmitted to the eddy current inspection equipment that evaluates it, identifies defects, marks the damaged areas and documents the results for future reference.
Inspection: Identification of weld seam defects in the internal metal layer of compound tubing
Diameter: 10–60 mm (0.4–2.4 in)
Eddy current testing is a fully automatic, easy-to-install nondestructive testing method that provides reliable test results to verify product excellence. It uses electromagnetic induction to detect flaws in all metal materials.
Eddy current testing works in multiple environments
One of the most important testing methods used by industry today, eddy current testing provides immediate feedback on product integrity, allowing correction of process changes before scrap develops and delivers reliable test results.
Eddy current testing is an excellent means of ensuring that tubing is leak-proof. Tubes are tested by encircling coils or multiple segment coils that completely surround the tube body. The eddy current test equipment paint-marks critical defects and assigns each tube to a sort class according to its quality. Test results are fully documented for future verification of tube quality.
PRÜFTECHNIK's rotating systems are designed specifically to identify longitudinal, homogenous cracks and fissures found at the surface of the test piece. They are used for products that have a tendency to show longitudinal defects but do not have seam welds. Because the encircling coil is ideal for finding short transverse defects, it is often used in conjunction with the rotating system for a comprehensive testing strategy.
PRÜFTECHNIK offers a series of rotating systems (RS20, RS35HS, RS65, RS140) to cover a wide range of tube diameters. They are particularly easy to operate and maintain and are extremely robust to withstand the industrial environment. Precise test piece guidance and a lift-off compensation system ensure accurate test results.
Eddy current inspection equipment suited for use with the rotating system includes the EDDYCHEK S, EDDYCHEK 5 advanced ROT and the EDDYCHEK 610, depending on the testing capabilities required.
Inline testing of tube, bar, and wire takes place in the production line at the time the material is produced. It assures that the material is free of cracks, holes and other material defects or periodic defects as even small surface defects can lead to defective end products, critical in items such as surgical instruments. Eddy current testing is extremely successful in detecting surface defects at various stages during the production process. For the best test results, encircling testing is used together with rotational testing. This testing method is also highly recommendable for hot environments such as hot rolled bar or hot rolled ferrous rod production.
Tubes are tested offline for a final quality check before delivery. Also, tubes that were sorted to scrap in the course of inline testing during production may be retested offline for more precise classification or for cutting out of defect-free sections. PRÜFTECHNIK supplies complete, customized conveyor systems and testing tables for offline inspection.
PRÜFTECHNIK offers a wide variety of eddy current inspection equipment that ranges from the most basic testers to powerful inspection systems with wide-reaching capabilites for integration into central production control systems and 8-channel inspection using multiple coil systems.
The eddy current sensor EDDYSENSOR is used instead of a light barrier to distinguish between individual test pieces in end-to-end testing.
Butt welds cannot be identified by simple detectors such as the light barrier or proximity switch. The EDDYSENSOR locates the butt weld using eddy current testing methods and transmits a signal to the control unit.
The EDDYSENSOR eddy current equipment is ideal for detecting a weld seam so that the seam can be positioned where needed for tube-forming processes such as bending.
Eddy current testing readily identifies flaws in the weld seam regardless of what welding procedure is used. The defects are color-marked and the tube is assigned a sort class according to its quality. Test results are fully documented for future reference.