Fused Deposition Modeling (FDM) is a well-established manufacturing method for producing both prototype and functional components. This study investigates the mechanical properties of FDM components by material and process-related influencing variables. Tensile tests were conducted on seven different materials in their raw filament form, two of which were fiber-reinforced, to analyze their material-related influence. To cover a wide range from standard to advanced materials relevant for load-carrying components as well as their respective variations, polylactic acid (PLA), 30% wood-fiber-reinforced PLA, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), a blend of ABS and PC, Nylon, and 30% glass-fiber-reinforced Nylon were selected. The process-related influencing variables were studied using the following process parameters: layer thickness, nozzle diameter, build orientation, nozzle temperature, infill density and pattern, and raster angle. The first test series revealed that the addition of wood fibers significantly worsened the mechanical behavior of PLA due to the lack of fiber bonding to the matrix and significant pore formation. The polymer blend of ABS and PC only showed improvements in stiffness. Significant strength and stiffness improvements were found by embedding glass fibers in Nylon, despite partially poor fiber–matrix bonding. The materials with the best properties were selected for the process parameter analysis. When examining the impact of layer thickness on part strength, a clear correlation was evident. Smaller layer thicknesses resulted in higher strength, while stiffness did not appear to be affected. Conversely, larger nozzle diameters and lower nozzle temperatures only positively impacted stiffness, with little effect on strength. The part orientation did alter the fracture behavior of the test specimens. Although an on-edge orientation resulted in higher stiffness, it failed at lower stresses. Higher infill densities and infill patterns aligned with the load direction led to the best mechanical results. The raster angle had a significant impact on the behavior of the printed bodies. An alternating raster angle resulted in lower strengths and stiffness compared to a unidirectional raster angle. However, it also caused significant stretching due to the rotation of the beads.

To solder metal parts efficiently, layers of oxides on the surfaces need to be removed. The use of formic acid vapour as a reducing agent is a valid alternative to liquid fluxes, i.e. organic or inorganic based. Fluxless soldering is growing in its applicability, especially in microelectronics packaging. Nevertheless, some residues are produced. This study focuses on the characterization of these residues, which are obtained by flowing nitrogen gas enriched with formic acid at 200 °C on Sn₃Ag_0.5Cu (SAC305) metal alloy, a widely used soldering material. The formation of microcrystals is observed and attributed to heat and mass transfer processes of the formic acid vapor. While there is a wealth of reported studies on soldering results under a formic acid atmosphere, there is a lack of information with regards to a specific understanding of the chemical compositions of these undesired residues. The second purpose of this study was to confirm the recently introduced method of producing Sn-based crystals under a formic acid atmosphere. X-ray diffraction (XRD), energy-dispersive X-ray (EDX) and infrared spectroscopy (IR spectroscopy) investigations allow us to assign the composition of the microstructures. Crystals of Sn formate, Sn oxide, and bimetallic Cu₆Sn₅ were detected and a mechanism of formation of these crystals was suggested.

The carbon content of steel affects many of its essential properties, e.g., hardness and mechanical strength. In the powder bed fusion process of metals using a laser beam (PBF-LB/M), usually, pre-alloyed metal powder is solidified layer-by-layer using a laser beam to create parts. A reduction of the carbon content in steels is observed during this process. This study examines adding carbon particles to the metal powder and in situ alloying in the PBF-LB/M process as a countermeasure. Suitable carbon particles are selected and their effect on the particle size distribution and homogeneity of the mixtures is analysed. The workability in PBF-LB is then shown. This is followed by an evaluation of the resulting mechanical properties (hardness and mechanical strength) and microstructure in the as-built state and the state after heat treatment. Furthermore, potential use cases like multi-material or functionally graded parts are discussed.

This paper explicitly establishes a modified creep model of a Sn–_3.8Ag–_0.7Cu alloy using a physical-based micromechanical modeling technique. Through experimentation and reformulation, steady-state creep behavior is analyzed with minimum strain rates for different temperatures 35 °C, 80 °C, and 125 °C. The new modified physical creep model is proposed, by understanding the respective precipitate strengthened deformation mechanism, seeing the dependency of the activation energy over the temperature along with stress and, finally, by integrating the subgrain-size dependency λ_ss. The new model is found to accurately model the creep behavior of lead-free solder alloy by combining the physical state variables. The features of the creep model can be explored further by changing the physical variable such as subgrain size to establish a structure–property relationship for a better solder joint reliability performance.