American scientists have developed a method for topology optimization of 3D printed products, allowing to obtain a structure which changes its angle and appearance as intended. Optimization is not by changing the design, and thanks to the distribution through it of three materials with different properties. As an example, researchers have created a plate which, when exposed to a magnetic field is rotated, whereby the image of her self portrait by Vincent van Gogh is changed to a picture of Edvard Munch’s “the Scream”. Article published in Science Advances.
Topological optimization allows for minimal use of material (and hence the smallest mass), while maintaining the desired engineer strength, function, and other parameters. Usually do topological optimization algorithms, which is obtained from the engineer a model that contains the attachment points, size and other basic settings, and then change the design, leaving these options unchanged. After this they calculate and analyze whether the key parameters unchanged, and decreased if the mass of the part.
There is another approach, in which the shape of the parts remains unchanged, but undergoes changes in its composition. A group of scientists from the Massachusetts Institute of technology under the leadership of Wojciech Matusik (Wojciech Matusik) has created a program for such topological optimization, it broke the model into voxels (the volumetric equivalent of pixels) and picked for each of them the right ratio of soft and hard material.
In the new work, the scientists used a similar approach, but to solve a different problem — the optimization of the structure of the object to obtain simultaneously the desired deflection of part of the structure under the action of the magnetic field and the desired visual change. For this, they created a set of three polymeric materials: soft, hard and transparent, but also rigid and opaque, which, moreover, contains ferromagnetic particles. This set allows you to set the optical properties (transparency and color) and mechanical — conventional hard material plays the role of basis of design, the composite magnetic particles is required to create moving parts, a soft polymer is used to create loops and other rotary mechanisms.