The ability to reduce vibrations is becoming increasingly important in 3D printing. Everything from semi-trucks to tennis rackets might benefit from structural optimization. Companies in the automobile and cycling sectors are beginning to investigate the potential of 3D printed springs for cushioning. The potential for commercializing digital and programmable foams is increasing, and metamaterials offer this opportunity.
Researchers from Deakin University, Nottingham Trent University, and the Royal Melbourne Institute of Technology have mapped out an exciting new direction for building comfortable chairs in this study. Their metamaterial springs, made with inexpensive material extrusion 3D printers, effectively dampen vibrations thanks to their “high-static and low-dynamic stiffness.” Testing showed that conventional polyurethane foam chairs with these QZS metamaterials embedded performed well.
Effective Design of the 3D Printed Springs
However, the design of 3D printed springs and its ease of use and low cost really sell it. The group did this without elaborate machinery but rather by building efficient structures from cheap parts. The result should outperform conventional springs even if it is more expensive to produce. It’s possible that 3D printing might see huge improvements if designers were allowed to experiment with novel designs at a cheap cost. Think about how auxetic, or zero Poisson ratio (ZPR), structures differ from others.
A rubber band, when stretched, often becomes narrower in the middle. On the other hand, auxetic materials or structures exhibit the reverse behavior, increasing in thickness when stretched and decreasing in thickness when compressed. In addition to their usefulness in applications such as helmets, these auxetics are renowned for their remarkable vibration-dampening qualities.
The group optimized their experimental outcomes by manipulating the springs’ buckling tendency. They created cylindrical springs that could be placed within standard foam seats, and the regulated ‘negative stiffness’ buckling characteristic of the 3D printed components increased performance while still absorbing energy. Various spring designs and materials were tested, and the article compared them to popular TPU filaments from manufacturers like eSun, Ninjatek, and Recreus.
There is a huge range in material qualities for 3D printed springs; Hobby King, for instance, has a four times higher UTS than other materials. The group used a nozzle size of 0.4 meters and a layer height of 0.2 millimeters to print their filaments, which they then dried. The eSun material was selected because of its low cost and high printability.
Beginning of New Era in Truck Cushioning with 3D Printed Springs
When combined with a foam, one design performed very well. Different combinations of foam and 3D printed springs performed better in severe circumstances and others in more moderate stress conditions, but these differences were not consistent throughout test cycles. It was difficult to tune the performance of the springs since there was instability in some regions. It was found that the sweet spot for performance was somewhere in the middle of the impact spectrum, whereas the extremes were often avoided.
Overall though, the performance of the foam improved when combined with a 3D printed spring. It was discovered that springs can and should be tailored to individual uses. This suggests that a substantial opportunity exists for the person who designs the ideal spring for a certain application. It may also imply that tailoring designs for specific use cases or implementing mass customisation are viable options.
According to their findings, these 3D printed springs varying degrees of effectiveness imply that they may be used to mitigate the particularly severe vibrations experienced by huge vehicles like trucks and buses. In such circumstances, the 3D-printed answer could even perform better than the conventional and high-end alternatives. Overall, it appears to be a low-cost and intriguing concept. Although there are still some kinks to work out, this strategy can potentially improve the riding experience for at least some people.
