A lightweight optical system to capture 3D measurements of surfaces with micron-scale precision in high-vibration environments, such as industrial manufacturing plants, has been engineered by researchers from Technische Universität Wien in Austria. This tool could improve quality control inspection for many high-tech products, from semiconductors to consumer electronics.
Vibrations make capturing precise 3D measurements on the assembly line difficult. To overcome this, samples are taken to a lab for analysis. If defects are discovered, however, the items produced in the meantime must be discarded. The new system combines a compact 2D fast steering mirror with a high precision 1D confocal chromatic sensor, allowing it to operate in the vibration-prone environment.
To bring this capability to the production floor, the researchers had to design a way to capture measurements without the bulky instruments used in the lab. The 1D confocal chromatic distance sensor used, developed by project research partner Micro-Epsilon, works similarly to a confocal microscope to measure displacement, distance and thickness, but is significantly smaller. The sensor was combined with the highly integrated fast steering mirror, which had a diameter of just 32 mm.
The system, weighing only 300 g and measuring 75 mm3 x 63 mm3 x 55 mm3, is designed to be mounted on a tracking platform placed on a robotic arm, and provides contactless 3D measurements of arbitrary shapes and surfaces.
A reconstruction process was also devised that uses the measurement data to create a 3D image of the sample’s surface topography. The compact 3D measurement system fits on a metrology platform that serves as a connection to the robotic area and compensates for vibrations through active feedback control.
The research is described in The Optical Society (OSA) journal Applied Optics.