Thanks to the way technology works, 3D printing requires ingenuity right from the planning stages. With most types of printers, extruders work layer by layer from the bottom up, meaning that a layer on an open space requires special support. Lack of support means parts will melt, sag, or break before the rest of the model can be completed. This is one of the many rules of 3D printing that every DIYer should know and always prepare for. Although useful, extra support pieces take longer to remove later, leaving residue or scarring. This also requires extra filament, so a large print can end up wasting a lot of it. But a groundbreaking new study led by researchers at the University of Twente offers a unique path planning strategy for creating unsupported horizontal overhangs.
Described as a “strategy based on wave propagation” or wave overhangs, the method achieves prints with “continuous paths that naturally run through complex geometry through diffraction-like behavior,” allowing them to overcome the usual complications and constraints like sagging. They can also be printed at a 90 degree overhang angle without supports. Usually angles greater than 45 degrees need it.
The article, published in Additive Manufacturing Letters, is now available for anyone interested in reading. Additionally, you can try the method with your own printouts. It is already deployable in the PrusaSlicer and OrcaSlicer forks according to the co-author – WaveOverhangs is an example.
How does it work and what is needed?
According to the article and the methods described by the researchers, the wave propagation strategy can be used on standard 3-axis FDM printers. It works with shapes or overhangs that use “arbitrary geometry” and does not require creating, planning, or printing supports such as structures or lattices. Instead, it relies on the physical wave propagation phenomenon of Huygens’ principle, which states that all points on a wavefront are new sources of wavelets. In printing, this looks like print paths drawn recursively as wavefronts, curved rings that undulate outward on the same plane, creating a better-supported edge in mid-air.
Imagine looking up and down and throwing a pebble into a pond, and watching the ripples or waves move outward one after another, all while being fully connected. It’s the same idea here. For rectangular or square shapes and edges, the wave pattern continues until the layer is filled as needed.
You don’t need anything special regarding materials or printer type. You can do it now with the right equipment. It’s all about using the right set of cutting tools that can accommodate wave designs. If you’re considering purchasing a printer to try all of this, there are a few things you need to know first, but researching techniques like this lowers the barrier to entry for complex prints. The wavy method suddenly opened the door to many other prints that would have required more materials, more time, and more care. Another trick for printing twice as fast, called flash fill, could have similar results for many projects.
