The feedstock in laser beam powder bed fusion of polymers (PBF-LB/P) is limited to a few materials with strict flowability requirements, compromising its economic efficiency and sustainability. A general route to nanoadditivate polymer powders for PBF-LB/P to tailor the polymer properties will be presented. The process employs laser produced nanoparticles that are directly adsorbed on the polymer powder, followed by drying, analysis and PBF-LB/P processing. The homogeneously dispersed nanoparticles on the polymer powder transfer their plasmonic or magnetic properties to the produced polymer parts with a nanoparticle loading below 0.1 wt%. To further reduce the required nanoparticle loading, electrophotographic powder application (EPA) is employed during PBF-LB/P, coating the parts with only two Ag-PA 12 layers and showing S. aureus and E. coli bacteria growth inhibition. The proposed approach can facilitate polymer powder functionalization and selective surface modification towards graded materials printing at reduced cost and waste generation.

Increasing electrification imposes challenging requirements on power electronics. These power electronics feature small functional structures, which are preferably made of pure copper and are built on sensitive ceramic-based substrates, so called Direct Bonded Copper (DBC) substrates. An innovative additive manufacturing (AM) approach employs the laser powder bed fusion (PBF-LB/M) process to manufacture the functional structures directly onto the DBC, enabling the reduction of manufacturing cost and effort. Processing of pure copper in the PBF-LB/M process is challenging due to its reflectivity and its thermal conductivity. Additionally, using a DBC in the PBF-LB/M process causes complex multi-material interactions. Focusing on the application, the processability of pure copper with a green and an infrared laser in the same machine setup was investigated. The influence of laser wavelength and process parameters on the resulting part properties was analyzed, differences between both wavelengths were pinpointed, and suitable parameter sets were identified.

Additive manufacturing offers great potential in the aircraft sector due to its high degree of design freedom and new material developments such as Scalmalloy®, a light aluminum alloy with high mechanical properties. Related works show a lack of knowledge about the additive manufacturing of Scalmalloy, so this paper aims to identify optimal process parameters. A design of experiment is performed and the hardness, tensile strength, and surface roughness are measured. After that, dimensional design parameters are investigated. With the optimized process parameters, a density of 99.87 % is achieved. The hardness is 168.5 HV0.3 and the tensile strength is 541.7 MPa after thermal treatment. Surface roughnesses between 41 and 20 Ra are measured depending on the build direction. Minimum manufacturable dimensions are defined for walls, cylinders, and inclination angles. The identified process parameters and the characterization of mechanical properties deliver fundamental knowledge to make Scalmalloy® usable for aircraft applications.

The surface quality of metal parts manufactured by laser assisted powder bed fusion varies significantly. To understand the surface formation process it is critical to understand the sintering/melting dynamics of particles. However, it is usually not possible to observe heating, melting and resolidification during the additive manufacturing process.

We present a setup that enables the in-situ optical and thermal imaging of the laser-initiated melting and the solidification of micrometer sized metal powder particles. The system consists of an optical tweezers setup that allows both a precise positioning of single particles as well as the melting of the particles using a ultrashort pulsed laser system operating at a wavelength of about 1.3 µm. Combining high-speed imaging offering a spatial resolution of 0.6 µm and a framerate up to 1,100,000 fps together with a micro-thermography system detecting spectral information between 2 µm and 5.5 µm the temperature dependent flow mechanics are measured.

Detailed knowledge about the physics of the PBF-LB/M process is still lacking, and the simulation of the fast and small-scale process is challenging. Especially the experimental validation of complex simulations lacks a suitable measurement technique for temperature distributions at high speeds and spatial resolution. The complicated process physics, specifically the rapidly changing emissivity in and around the meltpool, pose a severe challenge for usual thermographic approaches.

Here, we present first results of a hyperspectral measurement approach to reconstruct temperature and emissivity maps during the PBF-LB/M process in a custom manufacturing machine. The camera setup measures the thermal radiation of the process along a line at a rate of 20 kHz, spectrally resolved between 1 µm and 1.6 µm. When the meltpool travels perpendicularly across this line, a typical meltpool can be reconstructed by pointwise fitting for temperature emissivity separation, based on typical spectral emissivities from reference measurements.