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据悉，麻省理工学院（MIT）和代尔夫特理工大学（TU Delft）的科研人员报道了单材料3D打印中的高分辨率阴影和纹理渐变-调速熨烫技术的研究。 相关研究成果以“Speed-Modulated Ironing: High-Resolution Shade and Texture Gradients in Single-Material 3D Printing”为题发表在《UIST '24: Proceedings of the 37th Annual ACM Symposium on User Interface Software and Technology》上。
This study introduces a new manufacturing speed-regulating ironing method for programming visual and tactile properties in single-material 3D printing. Scientists use one nozzle to 3D print and the other nozzle to reheat the print area at different speeds, controlling the temperature response of the material. The rapid adjustment of the speed allows for fine reheating for high-resolution color and texture changes. The method was demonstrated in three temperature-responsive materials: foamed filament, wood fiber filament, and cork pellet filament. These filaments react to temperature by changing color, roughness, transparency, and gloss. The technical evaluation of the study showed that the research method had sufficient resolution and shade range to achieve surface details such as small text, photos, and QR codes on 3D printed objects. Finally, the study provides some examples of applications that refine the control of color, texture and shade in 3D printing, and demonstrate the new design capabilities of the speed ironing technology.
The speed-controlled ironing technology allows manufacturers to create objects with different colors and textures with high precision using only one material, as shown in the owl pictured below. Compared to other methods, this technique is faster and produces less scrap.
Figure 1: Speed-Modulated Ironing is a novel 3D printing technology for FDM 3D printers that enables continuous programming of visual and tactile properties at high resolution. New 3D printing technology enables the creation of unique items quickly and with less waste.
Figure 2: The process of ironing at a fixed speed. A) Printing: The first nozzle deposits a layer of material at low temperatures. B) Programming: After printing a layer, a second nozzle irons one layer at a higher but constant temperature. By varying the ironing speed, the degree of reheating can be controlled and thus the degree of activation of the material can be controlled. C) Thermal imaging camera image of the ironing process at a controlled speed. One area is ironed at a low speed to allow the print layer to be visibly reheated. The other area is ironed at high speed with no noticeable reheating. The nozzle temperature and nozzle height remain the same. D) Samples were printed with color gradient images made using the method used in this study.
Table 1: Ironing nozzle temperature and ironing speed range for the three materials used in the study method.
Figure 3: Ironing workflow.
Multi-material 3D printing technology enables manufacturers to create custom devices with multiple colors and different textures. But this process is time-consuming and wasteful, as existing 3D printers have to switch between multiple nozzles, often discarding one material before they can start depositing another.
MIT and Delft University of Technology are more efficient, less wasteful, and more accurate, using heat-responsive materials to print objects with a wide range of colors, shades, and textures in a single step.
"Speed-modulated ironing" uses a dual-nozzle 3D printer. The first nozzle deposits a thermally responsive filament, and the second nozzle passes through the printing material, using the heat to activate certain responses, such as changing opacity or roughness.
By controlling the speed of the second nozzle, the researchers could fine-tune the color, shading, and roughness of the heat-responsive filament by heating the material to a specific temperature. Importantly, this approach does not require any hardware modifications.
The researchers developed a model that predicts the amount of heat transferred to the material based on the speed at which the "ironing" nozzle will be conducted. They use this model as the basis for a user interface that automatically generates print instructions to achieve color, shade, and texture specifications.
People can make use of the speed-regulating ironing technology to create an artistic effect by changing the color of the printed object. This technique also allows for the creation of textured handles that make it easier for people with weak hands to grasp.
The study was presented at the ACM User Interface Software and Technology Symposium (UIST 2024), held October 13-16 in Pittsburgh.
Figure 4: The user interface of the speed-regulating ironing tool, including the generated main interface and the user's operation steps.
Fig. 5: Model of the maximum temperature of the material at different ironing speeds with a nozzle temperature of 340°C.
Figure 6: An example showing local shading variation. Each object is printed using one material, which is cork or wood filling.
Figure 7: An example of a scanned statue using research methods to process and produce local shading variations. A) Textured mesh files. B) Prints made with Corkfill. C) Another print that uses cork filling but has opposite brightness values. D) Printing with wood filler. E) Printed using green LW-PLA.
Figure 8: LW-PLA printed liquid container. The area ironed at low speed becomes opaque, while the area ironed at high speed remains translucent.
Adjust the speed to control the temperature
The researchers initiated the project to explore better ways to achieve multi-performance 3D printing with a single material. The use of heat-responsive filaments is promising, but most of the existing methods use a single nozzle for printing and heating. Before depositing material, the printer always needs to heat the nozzle to the desired target temperature first.
However, it takes a long time to heat and cool the nozzle, and there is a chance that the filaments in the nozzle will degrade when they reach higher temperatures.
To avoid these problems, the team developed an ironing technique that uses one nozzle to print the material, which is then activated by a second empty nozzle that only reheats the material. Instead of adjusting the temperature to trigger the material reaction, the researchers kept the temperature of the second nozzle constant and changed the speed at which it moved across the printed material so that it touched the top of the material layer slightly.
When the speed is adjusted, the ironed print layer reaches different temperatures. This is similar to the situation where a finger moves over a flame. If you move quickly, you may not get burned, but if you slowly drag your fingers through the flames, your fingers will reach a higher temperature.
The MIT team, in collaboration with researchers at Delft University of Technology, developed a theoretical model that predicts how fast the second nozzle must move to heat the material to a specific temperature. This model relates the output temperature of a material to its thermal response properties to determine the exact speed of the nozzle so that the printed object reaches a specific color, shade, or texture.
According to the researchers, there are a lot of inputs that can affect the results obtained. They're modeling something very complex and they want to make sure that the results are granular as well.
The research team delved into the scientific literature to determine the appropriate heat transfer coefficient for a unique set of materials and incorporate them into the model. They also have to contend with a range of unpredictable variables, such as the amount of heat that can be lost by the fan and the air temperature of the room where the object is being printed.
They incorporated the model into a user-friendly interface that streamlines the scientific process by automatically converting the pixels in the maker's 3D model into a set of machine instructions that control the printing speed of the object and the ironing speed of the dual nozzles.
PIC 9: Bicycle handlebar made by LW-PLA. The research method allows for a variation in roughness, which allows for grip and decorative effects.
Figure 10: A) Pattern used to test resolution and detail capabilities. B) Test pattern printed with infill wood. C) Filled cork. D) Black LW-PLA. E) Translucent "natural" LW-PLA.
Figure 11: Sample text readability test at different font sizes. A) Test images. B) Cork-filled samples. C) Filled wood samples. D) LW-PLA sample
Figure 12: A sample of tests evaluating the ability to reproduce photographs of different tones and details. A) Cork filled print. B) Filled wood prints.
Faster, finer manufacturing
They tested their method with three heat-responsive filaments. The first is foamed polymers, whose particles expand when heated, resulting in different shades, translucency, and textures. They also experimented with a filament filled with wood fibers and a filament filled with cork fibers, both of which could be charred, creating darker and darker shades.
The researchers showed how their method could create items such as partially translucent water bottles. To make the water bottles, they iron the foamed polymer at a low speed, creating opaque areas, and iron them at high speeds to create translucent areas. They also made a bicycle handlebar with different roughnesses out of foamed polymer to improve rider grip.
It takes more time to make similar objects using traditional multi-material 3D printing techniques, sometimes adding hours to the printing process, and consuming more energy and materials. In addition, speed-ironing produces fine-grained shading and texture gradients that are not possible with other methods.
This study introduces "Speed-Modulated Ironing", a new method to extend the capabilities of single-material 3D printing by enabling high-resolution control of visual shading and tactile texture gradients. In future work, the workflow will be further adapted so that the properties of the printed object are not limited to the outer surface, but also to the interior. Programming internally is particularly important when modifying mechanical properties locally. The researchers hope that their work represents a step towards more versatile, expressive and sustainable 3D printing. In the future, researchers hope to experiment with other heat-responsive materials such as plastics. They also wanted to explore the use of speed-controlled ironing to alter the mechanical and acoustic properties of certain materials.
Paper Links:
Speed-Modulated Ironing: High-Resolution Shade and Texture Gradients in Single-Material 3D Printing.https://doi.org/10.1145/3654777.3676456
Reprinted by Chen Changjun of the Yangtze River Delta G60 Laser Alliance