Weld seam inspection with phased array technology
- Published: August 3, 2018
Vogt Ultrasonics has announced the implementation of a fully automated phased array ultrasonic inspection solution for electron beam welds on rotors for asynchronous motors for a supplier to the automotive industry.
The system was designed as an integral part of a production line. The Vogt phased array ultrasonic inspection system works without immersion, with a bubbler technique. The component is locally moistened with water to couple the ultrasound, meaning that a complex and expensive drying stage isn’t required.
The use of phased array ultrasound technology leads to a considerable reduction in testing time. Phased array ultrasound systems are based on the principle of multi-element testing. A probe can have up to 128 elements, which can be activated electronically either individually or in a group. This creates focused ultrasound.
The inspection software creates two and three dimensional views of the component with the inspection areas showing the sizes and locations of detected defects. The advantages of this technique include beam focusing and control and the potential for linear or sectoral testing. This allows defects to be detected quickly and reliably with one probe, independent of direction.
The ultrasonic inspection system developed for this customer achieves cycle time reduction of a factor of 30 compared to conventional inspection.
After the rotors have been welded by the system, they are subjected to automatic quality control in the next step of the process. A robot feeds the rotors to the Vogt ultrasonic inspection system 24/7. Inspection involves testing the weld seams of the copper components on both end faces for imperfections. Optionally, the 0° marking of the cylindrical component can be made by means of a mandrel driven into the component by a pneumatic stamp. This enables local metallurgical inspection of the component at the site of the defect.
Inspection software evaluates test data automatically on the basis of previously defined evaluation criteria, and communicates the test result (“OK”/” NOT OK”) to the customer's central control system. Raster scan software with a stencil synchronization module is used due to the complex, non-contiguous test area. Subsequently the components are passed on by the robot into further production, or sorted out as “NOT OK.”