Path planning and inspection of complex-shaped 3D-printed composites based on robotic pulse-echo laser ultrasonic testing

Abstract

With the recent advancement in manufacturing, there has been an increasing demand for composite workpieces in the aviation industry. The emergence of composite 3D printing technology that enables the simplification and automation of composite manufacturing processes presents the possibility of replacing the manufacturing process of secondary structures in an unmanned aerial vehicle (UAV). To evaluate the applicability of the technology, a solution for automated non-destructive testing (NDT) that can be applied after the 3D printing process is needed. This study proposes an advanced approach to utilizing laser ultrasonic testing (LUT) for complex-shaped structures fabricated through continuous fiber 3D printing. To ensure accurate defect detection and localization, which are crucial factors in NDT, we propose a method that utilizes a six-degree-of-freedom (6-DOF) robot arm to control the position of the inspection target. By calculating the scan points and path through coordinate transformation and spatial rotation using a quaternion, all surfaces of the targets were inspected. This maintains a constant stand-off distance (SOD) while the sensing laser was vertically incident on the target surface, resulting in a high signal-to-noise ratio (SNR) of the ultrasonic signals. Inspection results have demonstrated the proposed technique to be suitable for detecting defects in complex-shaped 3D-printed structures.

Keywords:

• Robotic scanning
• laser ultrasonic testing
• additive manufacturing
• continuous fiber 3D printing
• complex-shaped structure

Acknowledgements

This research was supported by Unmanned Vehicles Core Technology Research and Development Program through the National Research Foundation of Korea (NRF) and Unmanned Vehicle Advanced Research Center (UVARC) funded by the Ministry of Science and ICT, the Republic of Korea (NRF-2020M3C1C1A01084220).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the National Research Foundation of Korea [NRF-2020M3C1C1A01084220].