For long, biological composite materials have been engineered to exhibit a variety of interesting structural properties. Efforts are being made by engineers to design engineering materials that closely resemble the unique properties of complex microstructures found in nature. In particular, what has intrigued researchers and material scientists is the challenge of varying the microstructures at specific locations to yield the desired mechanical properties. This needs controlling the fiber orientation within the engineered composites at very small scales to impart striking mechanical properties at micro levels.
In a recent breakthrough in engineering composites, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences found an innovative 3D printing method to control the precise arrangement of embedded short fibers in polymer matrices. The team called the method as ‘rotational 3D printing’ and demonstrated that using this they can uniquely program fiber orientation within composites to yield amazing material strength and stiffness, apart from exceptional damage tolerance. Furthermore, the exciting part of this technique is that by using various permutations and combinations of filler and matrix, exceptional electrical, optical, and thermal properties can be imparted to the printed materials.
Their work is published recently in the journal Proceedings of the National Academy of Sciences. The experiments are carried out in the Lewis Lab at Harvard University.
Rotating 3D Printing Nozzle to Control Flow of Ink for Arranging Embedded Fibers
The novel additive manufacturing technique is based on an approach that can control the rotational features of 3D printer nozzle with unprecedented precision. One of the collaborators contended that the nozzle approach could well apply to a range of material extrusion printing methods such as fused filament fabrication and robocasting. Furthermore, the method can accommodate any filler material, notably including glass fibers, carbon, and ceramic whiskers.
The novel 3D printing approach enables spatially programming engineered materials to vary the performance, such as increasing the damage tolerance. The work, opines one of the material scientists at MIT, will pave way for structural innovations, notably for fabricating bio-inspired composites.