Robotic sample manipulation for stress and texture determination on neutron and synchrotron X-ray diffractometers

In this paper we report on a new robotic arm system for fast, accurate and flexible sample manipulation for stress and texture analysis in geometrically complex engineering components on neutron and synchrotron X-ray diffractometers. A Staeubli serial six-axis robotic arm offering full six degrees of freedom for sample movement, with a spatial positioning accuracy of the order of tens of microns has been commissioned. Reverse engineering and 3D visualization techniques are employed to control the sample manipulation procedure. Two basic applications of the system, one for stress measurements using synchrotron X-ray diffraction using the sin2 ψ inclination method, and one for pole figure determination for texture analysis using neutron diffraction, are presented. The former required measurements at eight angles for each measurement location; the latter a full quadrant of solid angle with the centre of the sample maintained stationary. With new robotic arms being produced with higher payloads (the current one is limited to 9 kg), but similar positional uncertainties, robotic sample manipulation offers very flexible measurement strategies for complex geometries, without the need for repeated manual intervention for sample reorientation.