2023-11-21 23:01:30
In recent years, we have witnessed a boom in soft robotics: robots made from soft materials allow elastic deformations and minimize the risks often linked to the use of rigid materials such as steel or aluminum. . The advantages of this type of robotics are sought in a large number of fields such as health, where human-machine interactions and the gripping of fragile or complex objects are tested. Today, robotics is increasingly affected by the growth of additive manufacturing: the two technologies are being combined more in many sectors to design more efficient solutions. However, with the rapid development of materials compatible with 3D printing, notably silicone for example, we are witnessing a series of new applications in robotics. This is the case of the one presented by MIT and ETH Zurich which have developed a somewhat unusual 3D printed robotic hand.
Stakeholders in this project successfully transformed slow-curing plastics into 3D printing. These plastics are elastic, more durable and allow a handheld robot to print them in a single pass. This success was made possible by cooperation with the American startup Inkbit and its technology. They worked together on the study “Vision-controlled jetting for composite systems and robots” with the aim of producing complex, high-resolution structures with different material properties and recreating the functions of natural organisms in synthetic form. They combined 3D printing with laser scanners and a feedback mechanism. This approach enabled 3D printing of low-viscosity, slow-curing polymers with excellent elasticity. It is thus possible to produce complex and resistant materials used for robots, composed of different high-quality materials and having a combination of elastic and rigid structures. The continuous printing of delicate parts and cavity structures similar to those of a human being also opens up new perspectives in soft robotics. The study results were published earlier this month in the journal Nature.
The study shows new possibilities for soft robotics and 3D printing. (Image: Thomas Buchner et al; Nature)
As part of the study, ETH Zurich and Inkbit tested their approach in various application examples. They have produced a wide range of high-resolution composites and various robots, including robotic hands, heart pumps, and other metamaterial structures. One of the most notable examples is a robotic hand with artificial bones and ligaments. It is made of different polymers and has cavities to house the sensors. It was printed in one go and no further assembly was required. One of the reasons for this is the polymers used. “ We might not have produced this hand with the fast-curing polyacrylates we used for 3D printingexplains Thomas Buchner, doctoral student in the robotics group at ETH and first author of the study. We now use slow-curing thiolene polymers. They have very good elastic properties and return to their original state much faster than polyacrylates following being bent. » These properties also make thiolenic polymers ideal materials for producing the elastic bands of the robotic hand. In addition, the rigidity of the thiols can be adjusted very finely and therefore adapted to the requirements of soft robots. “ Robots made of soft materials such as the hand we developed have advantages over conventional metal robots: because they are flexible, the risk of injury is reduced when working with humans, and they are better adapted handling fragile goods“adds Robert Katzschmann, professor at ETH.
Combining 3D printing and soft robotics
The approach taken by MIT, ETH and Inkbit for the robotic hand also offers high throughput and an automated multi-material printing process with high scalability. The aforementioned slow-curing polymers (thiolenes and epoxies) played a key role in the creation of the robotic hand. However, the possibility of processing them by 3D printing also depends on the technology used. Until now, only fast-curing polymers might be processed by 3D printing, because a device scrapes off irregularities following curing and thus guarantees parts of suitable quality. However, slow-curing polymers risk blocking such a scraping device.
The 3D-printed robotic hand consists of artificial bones, tendons and ligaments made of different materials, including soft, elastic plastics. (Image: Thomas Buchner et al; Nature)
This is the advantage of Vision Controlled Jetting technology from the American startup Inkbit, from MIT. With this printing technology, an inkjet process, nozzles apply the desired viscous material to each point, which is hardened layer by layer by a UV lamp. The special feature of this technology is that a 3D laser scanner then checks the printed layer for irregularities, which are then taken into account when applying the next layer. “ A feedback mechanism compensates for these irregularities when printing the next layer by calculating in real time precise adjustments to the amount of material to be printed“, explains Wojciech Matusik, professor at MIT and co-author of the study. This means that the scanning system captures the 3D structure and allows immediate adaptation through a digital feedback loop. This eliminates the need for additional mechanical solutions and facilitates a contactless process that allows printing of continuously curing plastics with different elasticities. Wax is used as the printing medium, which is then melted at 60 degrees Celsius.
One of the difficulties encountered by the team during this research project was that some printed parts encountered a warping problem. Additionally, the layers of the multi-material prints did not always adhere well, although this might be improved in the future. The overall high resolution, fast printing process and wide range of materials with different properties can already enable a variety of hybrid, soft/rigid robots and other applications. MIT and ETH Zurich were able to optimize Inkbit’s printing technology for the use of slow-curing polymers by testing various applications. They will now focus on exploring other possibilities and trying to print and test even more complex structures. Inkbit’s ultimate goal is to develop and commercialize the technology. To learn more regarding the study, click ICI.
What do you think regarding the use of additive manufacturing in soft robotics? Share your opinion in the comments to the article. Find all our videos on our channel YouTube or follow us on Facebook or Twitter !
*Cover photo credits: ETH Zürich, Thomas Buchner
Receive post notifications Unsubscribe from notifications
1700626335
#ETH #Zurich #demonstrates #benefit #combining #additive #manufacturing #soft #robotics
