Researchers from MIT and Delft University of Technology have developed a more efficient and less wasteful technique for multi-material 3D printing that leverages heat-responsive materials. Their method, called speed-modulated ironing, utilizes a dual-nozzle 3D printer to deposit a heat-responsive filament and then pass a second nozzle over the material to activate specific responses using heat. By controlling the speed of the second nozzle, the researchers can finely tune the color, shade, and roughness of the printed material without the need for any hardware modifications.
The team developed a model that predicts the amount of heat the “ironing” nozzle will transfer to the material based on its speed, allowing for precise control over the color, shade, and texture of the heat-responsive filaments. This model serves as the foundation for a user interface that automatically generates printing instructions to achieve specific color, shade, and texture specifications. The researchers envision using speed-modulated ironing to create artistic effects by varying the color on printed objects or producing textured handles that are easier to grasp for individuals with hand weakness.
The collaboration between MIT and TU Delft researchers led to the exploration of better ways to achieve multi-property 3D printing with a single material. The ironing technique developed by the team allows for material to be printed using one nozzle and then activated by a second, empty nozzle that only reheats it. By adjusting the speed of the second nozzle rather than the temperature, the researchers can achieve a variety of colors, shades, and textures in the printed object. This approach eliminates the need to constantly heat and cool the nozzle, reducing printing time and the risk of filament degradation.
The team created a theoretical model to predict the necessary speed of the second nozzle to heat the material to a specific temperature, taking into account various inputs that could affect the results. The model includes heat transfer coefficients for specific materials and other variables like heat dissipation and room temperature. This model was integrated into a user-friendly interface that simplifies the process for makers, automatically translating their 3D models into machine instructions that control the speed at which the object is printed and ironed by the dual nozzles, making the fabrication process faster and more precise.
The team tested their approach with three heat-responsive filaments, including a foaming polymer, a filament filled with wood fibers, and one with cork fibers. They demonstrated how speed-modulated ironing could produce objects like water bottles with varying shades and translucencies, as well as a bike handle with varied roughness for improved grip. Compared to traditional multi-material 3D printing methods, speed-modulated ironing was faster, more energy-efficient, and produced finer shade and texture gradients that were previously unachievable.
In the future, the researchers plan to experiment with other thermally responsive materials, such as plastics, and explore using speed-modulated ironing to modify the mechanical and acoustic properties of materials. Their innovative approach to multi-material 3D printing opens up new possibilities for creating customized objects with multiple colors, shades, and textures in a more efficient and sustainable manner. The research will be presented at the ACM Symposium on User Interface Software and Technology, showcasing the potential of speed-modulated ironing for advancing 3D printing technology.