July 24, 2024
3D Printing

New 3D Printing Resin Enables Variable Stiffness in Single Objects

In the field of biomedical engineering, the development of devices for use inside or on the human body often overlooks the importance of mimicking the natural softness of biological tissues. However, a breakthrough has been made with the creation of a 3D printing resin that allows for variable stiffness within a single object.

While our bodies consist mostly of soft tissues, medical implants and wearable electronics typically incorporate rigid components. Even when synthetic materials are used to add flexibility, there is often a noticeable boundary between the soft and rigid sections. These boundaries can lead to discomfort, reduced functionality, and mechanical failure under stress.

To address this issue, scientists from Lawrence Livermore National Laboratory (LLNL) and Meta have developed a one-pot thiol-ene-epoxy 3D printing resin that mimics the gradual stiffness transition found in biological tissues. Similar to other photosensitive resins, this material solidifies when exposed to specific light patterns. By controlling the intensity of the light, the stiffness of the solid can be adjusted. This allows for the creation of a single-piece object that smoothly transitions from soft to rigid, with the material’s toughness increasing up to tenfold along the gradient.

In a demonstration of the technology, the researchers used the resin to 3D print a finger-worn device capable of converting text messages into braille. The wearable contains air pads that, when connected to an air pump, replicate the sensation of touching raised braille characters on the user’s fingertip.

The lead scientist of the project, Dr. Sijia Huang from LLNL, explained the significance of the research, stating, “This work has been looking into whether we can design continuous mechanical gradients from soft to stiff in a single resin system. Here, we’re printing everything we’re seeing, just using the light dosage to control the modulus.”

The findings of this study were published in the journal Matter. Another material with similar qualities, inspired by squids, was previously developed by a team at Case Western Reserve University.

This breakthrough in 3D printing resin technology has the potential to revolutionize the design and production of biomedical devices. By allowing for a seamless transition between soft and rigid materials, the discomfort and limitations associated with existing devices can be overcome. Further research and development in this area could pave the way for more comfortable and functional wearable electronics, medical implants, and other bio-inspired technologies.