In this paper, a new possibility of fabricating a metal lattice structure with a continuous rod is demonstrated. A multi-layer, periodic, and aperiodic lattice structure can be manufactured with a continuous thin rod by bending it with a repetitive pattern. However, joining their nodes are challenging and an important problem to solve. This paper is investigating the joining of nodes in a loose lattice structure by delivering materials through the dipping process. Both liquid state (epoxy) and solid-state (inorganic particles) joining agents are considered for polymer–metal and metal–metal bonding, respectively. Liquid Carrier Systems (LCS) are designed considering their rheological behavior. We found 40% solid loading with the liquid carrier system provides sufficient solid particles transfer at dipping and join the lattice node using transient liquid phase bonding (TLP). 3D metal lattice structures are constructed, and their mechanical properties are investigated. The lattice structure shows comparable strength even with smaller relative density (< 10%). The strength and elastic modulus of all the fabricated samples decreases with the increase in cell size, which is consistent with the traditional wisdom.

Micro-scale inorganic particles (d > 1 µm) have reduced surface area and higher density, making them negatively buoyant in most dip-coating mixtures. Their controlled delivery in hard-to-reach places through entrainment is possible but challenging due to the density mismatch between them and the liquid matrix called liquid carrier system (LCS). In this work, the particle transfer mechanism from the complex density mismatching mixture was investigated. The LCS solution was prepared and optimized using a polymer binder and an evaporating solvent. The inorganic particles were dispersed in the LCS by stirring at the just suspending speed to maintain the pseudo suspension characteristics for the heterogeneous mixture. The effect of solid loading and the binder volume fraction on solid transfer has been reported at room temperature. Two coating regimes are observed (i) heterogeneous coating where particle clusters are formed at a low capillary number and (ii) effective viscous regime, where full coverage can be observed on the substrate. ‘Zero’ particle entrainment was not observed even at a low capillary number of the mixture, which can be attributed to the presence of the binder and hydrodynamic flow of the particles due to the stirring of the mixture. The critical film thickness for particle entrainment is $${h}^{*}=0.16a$$ h ∗ = 0.16 a for 6.5% binder and $${h}^{*}=0.26a$$ h ∗ = 0.26 a for 10.5% binder, which are smaller than previously reported in literature. Furthermore, the transferred particle matrices closely follow the analytical expression (modified LLD) of density matching suspension which demonstrate that the density mismatch effect can be neutralized with the stirring energy. The findings of this research will help to understand this high-volume solid transfer technique and develop novel manufacturing processes.

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Cellular solids have diverse potential applications such as mechanical, thermal, phononic, and biological applications. However, the fabrication of cellular structure with the 3D printing process is often infeasible due to the anisotropies, fabrication imperfections, and for that, a significant amount of resources is required. In this paper, we have analyzed the preprocessing knowledge base of extrusion-based 3d printing and contemplated it with post-processing performance measurement for lattice structure printing. We considered cuboid cell type micro and macro lattice structures for our analysis. To compare cuboid with truss, a single unit cell is printed, and its compressive strength is measured. Three different patterns (traditional micro infill, interlocked macro assembly, traditional macro strut) are designed and fabricated to investigate the effects of design strategy and mechanical performance. We have found anisotropic behavior in the fabricated structure as expected in traditional print. However, interlocked assembly based cuboid structure has demonstrated uniformity for both inplane and out of plane load. Furthermore, we have found that the applied load type has a bigger impact on the performance of the printed structure and should be considered during their preprocessing stage.