Darkfield-scattering surface analysis in powder-based AM-processes: analysis of a multi-wavelength approach

The availability of fast and robust sensors in fabrication of advanced instrumentation on the micro- and nanoscale drives innovation. Amongst others, we have recently shown progress towards high-dynamic range optical surface profilometry exploiting spectral imaging techniques. In this study, we demonstrate the application of a laser-based multi-wavelength dark-field scattering technique for the surface analysis of powder-based Additive Manufacturing (AM) processes. This novel approach leverages the dynamic range of multi-wavelength lasers to achieve high-resolution characterization of material surfaces. We detail the technique’s efficacy in analyzing surface roughness, a critical factor affecting the mechanical properties and performance of AM parts. The results indicate that our approach can detect subtle, μm-sized variations in surface texture, offering a robust tool for improving the quality control and optimization of AM processes. The results showed that an axial resolution of down to 1 μm at a height range of multiple millimeters is achievable. The scanning of large areas with a size of 200 x 500 mm² can be performed at frame rates surpassing 100 fps will be achievable. This method presents a significant advancement in the precision and applicability of surface analysis techniques in additive manufacturing, ensuring better control over the fabrication process and resulting in higher-quality end products.