Carnegie team harnesses warpage to 3D print self-folding plastics

Known as Thermorph, the method relies on a natural phenomenon called ‘warpage’ that sometimes occurs when printing thermoplastic. Generally a nuisance, the Carnegie team has adopted warpage to its advantage. It used software algorithms developed in-house to precisely control an off-the-shelf FDM (fused deposition modelling) printer, combining the plastic with rubber-like materials and depositing them in such a way as to encourage warpage.

The objects emerge from the 3D printer as flat, hard plastic. When the plastic is placed in water hot enough to turn it soft— but not hot enough to melt it — the folding process is triggered.

“The software is based on new curve-folding theory representing banding motions of curved area,” said Byoungkwon An, a research affiliate at Carnegie’s Human-Computer Interaction Institute (HCII). “The software based on this theory can compile any arbitrary 3D mesh shape to an associated thermoplastic sheet in a few seconds without human intervention.”