3D Printing of Self‐Organizing Structural Elements for Advanced Functional Structures

Abstract

In reality, the load bearing capacity of the diamond structure shown is not only based on its overall design and cell geometry, but on the exact connection of the individual struts, also. Thinking of different length scales, one may consider the use of related structures as a metamaterial which is leading to the question of its manufacture. Moreover, there is the demand of locally programming material functionalities within a structure making it "smart," that is, enabling an autonomous sensing and reacting to changes in its environment. State of the art manufacturing technologies are typically based on a computer-aided design and manufacturing (CAD-CAM) process chain, starting with the design of a model on a computer. Despite the parts function, design needs to consider available technologies for the parts manufacture and realization. [2,3] Within this respect, additive manufacturing (AM) technologies are enabling the highest freedom which has, in turn, stimulated new design strategies. Not all of them are exactly new, e.g., biomimetic or bionic design, but with the vision of realizing extremely complex structures with minimum restriction in design these concepts have gained new momentum. The key question is how to make designs that are using less material and energy and which shape or form is the best? In this context, minimal surface membranes appear particularly attractive, as, per definition, they are established with minimum use of material and their shape is a result of minimization and homogenization of tensile stresses. In this context "Tensile Stress Design" is a prominent example from engineering, which has become popular even before modern computing has enabled advanced modeling because related structures can be obtained by selforganization, e.g., by the use of soap bubble models. [4,5] Self-organization is the dynamic and adaptive process through which systems achieve and, also, maintain structure without any additional external control. Self-organization is not restricted to a certain size regime, but its use for the manufacture of objects requires a precise knowledge about how to trigger self-organization processes, how to guide them into the right direction for obtaining the desired shape and how to rest them in order to obtain structural integrity of the final object.The present communication will introduce a strategy for 3D printing of structures which partially melt, form a transient liquid phase and self-organize governed by minimizing their A shape evolution approach based on the thermally activated self-organization of 3D printed parts into minimal surface area structures is presented. With this strategy, the present communication opposes currently established additive manufacturing strategies aiming to stipulate each individual volumetric element (voxel) of a part. Instead, a 3D structure is roughly defined in a 3D printing process, with all its advantages, and an externally triggered self-organization allows the formation of structural elements with a definition greatly exceeding the volume...

Self‐Organization Postprocess for Additive Manufacturing in Producing Advanced Functional Structure and Material

“…This effect causes the membrane thickness to shrink from originally 3 mm to below 2 mm. As discussed in detail in a previous publication, [ 14 ] the shape evolution during posttreatment is governed by an interplay between the viscous flow of the material infiltrating the frame (thus reducing the amount of molten filler available in the membrane) and the flow guided by surface tension, which leads to the minimization of surface energy for the given boundary conditions.…”

“…The present process was introduced in a former publication, in which 2D parts with optical transparency were obtained. [ 14 ] The self‐organization in 3D structures is further developed in this article, which shows the potential capability for the self‐organization of complex geometries.…”

Three-Dimensional Printed Polyamide 12 (PA12) and Polylactic Acid (PLA) Alumina (Al2O3) Nanocomposites with Significantly Enhanced Tensile, Flexural, and Impact Properties

“…At this state, the polymeric material is extruded from a nozzle that moves in XYZ space. FFF has received continuous scientific and technological interest, especially when it comes to the manufacturing of thermoplastic polymeric material components [ 32 , 33 ] and/or polymer composites, e.g., nanocomposites [ 34 , 35 ] and fiber-reinforced composites [ 36 , 37 ]. To date, several achievements have been made on the level of the 3D printer as a machine; namely, the printer’s accuracy, automation, printer parts, e.g., nozzles, heat-able beds, etc., while all could affect the quality of the final manufactured parts [ 38 ].…”