Coaxial Laser Metal Deposition with wire (LMD-w) is a valuable complement to the already established Additive Manufacturing processes in production because it allows a direction-independent process with high deposition rates and high deposition accuracy. However, there is a lack of knowledge regarding the adjustment of the process parameters during process development to build defect-free parts. Therefore, in this work, a process development for coaxial LMD-w was conducted using an aluminum wire AlMg4,5MnZr and a stainless steel wire AISI 316L. At first, the boundaries for parameter combinations that led to a defect-free process were identified. The proportion between the process parameters energy per unit length and speed ratio proved crucial for a defect-free process. Then, the influence of the process parameters on the height and width of single beads for both materials was analyzed using a regression analysis. It was shown that linear models are suitable for describing the correlation between the process parameters and the dimensions of the beads. Lastly, a material-independent formula is presented to calculate the height increment per layer needed for an additive process. For future studies, the results of this work will be an aid for process development with different materials.

The applications of graphite nanoparticle dispersions emerge due to the increasing importance of printed electronics and microelectronics, lithium-ion batteries, and supercapacitors. Promising technologies are inkjet printing processes, which are significantly influenced by the dispersion stability. Achieving stability is particularly challenging for nanoparticle dispersions due to the strong attractive forces emanating from the large particle surfaces. Despite the significance attributed to stability, it is predominantly investigated empirically. The only existing model to mathematically describe interparticle forces is given by the DLVO theory. This paper uses the extended DLVO theory to model the stability of aqueous graphite dispersions. Furthermore, the influences arising from an electrosterically stabilizing dispersant, in this case polyvinylpyrrolidone (PVP), were incorporated in the model. Experimentally data obtained from sedimentation analyses concur with the DLVO theory prediction. Due to the universality of the model, it is expected to be applicable to different material and dispersant systems.

Water-based processing of electrodes is associated with an enhanced environmental footprint for lithium-ion battery (LIB) production in conjunction with reduced costs. This trend is accompanied by an increasing demand for electrode dispersion processing in inkjet printing. However, most of the dispersion components show a low inherent dispersibility with poor stability in aqueous formulations. This is particularly important when it comes to qualifying electrode dispersions for use in inkjet printing, since the effect of agglomeration and sedimentation effects must be effectively prevented. Therefore, additives are needed to improve the dispersive behavior. This paper analyzes the suitability of dispersants for organic electrode components, in particular graphite and carbon black. An empirical approach was devised on the basis of comprehensive theoretical considerations. Empirical investigations revealed that the utilization of polyvinylpyrrolidone (PVP) favored the enhanced stabilization of graphite nanoparticles. The addition of Triton X-100 (TX-100) resulted in an improved stabilization of carbon black. Based on these empirical studies, a methodology was derived, which supports the application of suitable dispersants in printable dispersions.

Laser powder bed fusion (L-PBF) is increasingly used to fabricate functional parts used in safety-relevant applications. To ensure that the sophisticated part specifications are achieved, 100% quality inspections are performed subsequent to the buildup process. However, knowledge about the detectability of defects in L-PBF parts using NDT methods is limited. This paper analyzes the suitability of NDT techniques in an ex situ environment, in particular active infrared thermography, neutron grating interferometry (nGI), X-ray computed tomography, and ultrasonic testing for the examination of L-PBF parts made from Inconel 718. Based on a test specimen with artificially inserted defects with varying dimensions and depths, these NDT techniques were compared in terms of their attainable resolution and thus defect detection capability. The empirical studies revealed that nGI shows the highest resolution capability. It was possible to detect defects with a diameter of 100–200 m at a depth of 60–80 $${\upmu } \hbox {m}$$μ m . The results are discussed with regard to their relevance for the examination of L-PBF parts and thus not only contribute to a better understanding of the potential of the NDT techniques in comparison but also assist stakeholders in additive manufacturing in evaluating the suitability of the NDT techniques investigated.

In binder jetting (BJ), an ink is inserted layerwise into a powder bed to selectively bond the particles in the cross-section of a part. By predicting the penetration depth of the ink, the ideal layer thickness for BJ can be set. Each layer should be penetrated with ink. Insufficient penetration will result in a poor layer bond and a low strength of the part; over-penetration will impede a dimensionally accurate production, as the ink will leak from the sides of the part and unintentionally solidify the powder in these areas. The Washburn equation has been used for the calculation of the penetration depth in various fields, such as hydrology or with loose powders. However, a transfer to the BJ process is difficult due to the preferably compact powder bed and the fine particles. In more compact powder beds, the small radii with their greater capillary pressure and their distribution in the layer have a high influence on the penetration depth. This work shows an adaptation of the Washburn equation for powder beds in BJ and a new approach to determine the effective pore radius for calculating the penetration depth. A weighted pore radius was introduced, which accounts for the spatial distribution of the pores in the powder bed and the acting capillary pressure. The validation was performed with two different powders by experimentally simulating the BJ process through the infiltration of a drop into a powder bed. The weighted radius was used in the Washburn equation to calculate the penetration depth. The results were compared with those models from the literature and experimental data, and a good agreement between the calculation and the experiment was found.