Fri, 22 October, 2021
The aim of the Tacoma project is to provide the capability for rapid inspection of composite components using robotic methods. Using robots allows for more repeatable, precise and faster scanning compared to human operated techniques. This allows for higher throughputs of components and higher quality data to be collected. The robots used in this project were a single Universal Robotic UR10e robot (UR10) and a pair of smaller UR3es that would work in unison. These are shown in Figure 1.
Figure 1. Left - Image of the UR10 robot being used for a through transmission air coupled ultrasonic inspection. Right - Image of the UR3 robot pair being used for an X-Ray inspection
The inspection uses two non-destructive evaluation methods: air coupled ultrasound transducers and X-Ray radiography. For more information on these, please see the following links:
The Tacoma software has been designed to incorporate both sensor types with either robot setup. Path planning of the robot is done externally as the software is primarily for data collection and analysis. Various streams of data are fed into to the software and an interpolation algorithm computes the physical position in 3D-space. These points are then tessellated to produce a solid surface with which the user can interact. An A-scan is associated with each point where the colour of the point is determined by a gate applied to the current A-scan and a user-selected colour palette. The gate can be configured by the user during post-processing.
Figure 2. Tacoma software - 3D visualisation of the air coupled ultrasonic data in the Tacoma software
A depiction of the data analysis in the Tacoma software is shown in Figure 2. The A-scan marker can be moved in the 3D view to display the A-scan data associated with any point on the surface. The A-scan window on the right hand side of Figure 2 is used to view the scan data, while the maximum amplitude of the scan data is correlated to the colour that the point appears on the 3D plot. Flaws can be sized using in built measurement tools. A CAD model can be imported in order to correlate points on the scan with points on the component.
Digital Radiography (DR) data are processed in a similar way with the exception that a radiographic image rather than an A-scan is associated with each 3D point. At the end of a scan, the application proceeds to stitch the individual images together to form one image of the entire part that was subjected to XCT scanning. Figure 3 shows a single XCT image of part of a paperclip as shown in Tacoma software.
Figure 3. Tacoma software - XCT image acquisition demonstration
For more information on the Tacoma software, please contact crystal@twi.co.uk.