A team of scientists from the University of San Diego (CA, USA) has developed a novel strategy for 3D printing objects that can ‘grow’ after being printed in response to heat.
Having previously been limited by the size and shape of conventional 3D printers, the team hopes this new foam-like material will have diverse applications in many fields including architecture, aerospace and biomedicine.
Focusing on the limitations of stereolithography, the team reported in ACS Applied Materials & Interfaces that the aim had been to create an expandable resin that could 3D print larger objects utilizing an inexpensive and commercially available machine, with less of a requirement for fastening multiple parts together.
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Many different resin formulations were tested until one was identified that could expand to a larger size in response to heat. This material was then used to 3D print a hollow lattice, featured in a video from the scientists.
When heat was applied to the lattice in an oven, a volatile component was released as gas, causing the creation of a porous foam-like material up to 40 times larger in volume than the object first printed.
Other objects the team tested included a boat that expanded to be able to carry approximately 20 times more weight and a wind turbine capable of producing a small amount of electricity.
Although the material may not be especially strong at this stage, the team envisions applications in cushioning, airfoils and buoyancy aids in the future.
Sources: Wirth DM, Jaquez A, Gandarilla S, Hochburg JD, Church DC, Pokorski JK. Highly expandable foam for lithographic 3D printing. ACS Appl. Mater. Interfaces. 12(16) 19033–19043 (2020); www.acs.org/content/acs/en/pressroom/presspacs/2020/acs-presspac-may-13-2020/expandable-foam-for-3d-printing-large-objects-video.html