3D printing with capillary structures: progress in multi-material manufacturing

Researchers at the Lawrence Livermore National Laboratory (LLNL) have developed new approaches to multi-material additive manufacturing. Using capillary structures, they can direct liquids into lattice structures and cure them there. This process makes it possible to combine materials with very different properties and produce complex structures that would not be possible using conventional methods.

The core of the process lies in specially designed grid cells that absorb liquids through capillary forces and guide them precisely into desired patterns. This makes it possible to combine soft materials with infused liquids, which subsequently harden and acquire stable properties. The researchers emphasize that this technique is particularly suitable for applications with high strength-to-weight ratios or large specific surface areas.

“By decoupling some of the printing and patterning techniques, you could achieve some complex multi-material structures, and you wouldn’t always have to be able to print the material,” said Hawi Gemeda, Materials Engineering Division (MED) staff engineer and the paper’s lead author.

“Essentially, you’re trapping droplets or streams of liquid inside open pores, where they’re not fully enclosed,” said MED researcher and co-author Nik Dudukovic. “It allows us to pattern together the soft material the lattice is made from, and the infilled liquid that subsequently solidifies, into a stiff material to produce some interesting mechanical properties.”

The process, which was first presented in Advanced Materials Technologies, could be used in areas such as biomedicine, aerospace and energy storage. The researchers are currently investigating the extension of the method to ceramic and metallic materials and its use in self-healing structures.

“My hope is that it inspires and motivates the AM community to use some of our developments to expand multi-material, multiscale capabilities,” Gemeda said.