During the casting of ship propellers small pores and tiny cracks often arise within the material, which can lead to failure if not repaired. Until now testing for defects has been carried out manually, but it is difficult to achieve consistent and reproducible results with manual processes of this kind. To overcome this problem the USA’s MPR has, in collaboration with a specialised systems office, developed a new automated ultrasonic system for inspecting marine drive components such as ship propellers.
A small lightweight measurement system is used with a mobile scanning device. The system includes all hardware and software components including instrument control, motion control, data acquisition, fast imaging of A, B and C scans, and evaluation and documentation tools.
The system is capable of recording large amounts of digitised ultrasonic testing data in real-time. On site, the system scans an inspection area of up to 900mm by 450mm and achieves speeds of up to 200mm per second. The mobile inspection system can be freely positioned on the propeller geometry, or the scanning device can be attached by suction cups in vertical and horizontal positions.
The mobile inspection and scanning system is available for on-site inspections in foundries, at propeller manufacturers and in drydock. Use of the system reduces the time required for defect inspection and makes interpretation of the results far easier and more reliable.