It is called "liquid phase 3D printing," and the technique promises a method of making conductive metal objects – and doing it with metal alloy printing inks whose melting point is slightly above room temperature.

A team of scientists at the Technical Institute of Physics and Chemistry at the Chinese Academy of Sciences, have developed a new conceptual method of liquid-phase 3D printing for quickly making conductive metal objects.

The scientists say that, at least as compared to air-cooling in a conventional 3D printing process, their liquid phase manufacturing cools much faster and as a result, significantly improves the speed in fabricating a given target metal object.

The lead authors of the research, Liu Jing and Wang Lei, say the technique offers a number of improvements by using metals with a low melting point such as a four-element alloy called Bi35In48.6Sn16Zn0.4 they developed and use as printing ink. The metal alloy has a startlingly low melting point, somewhere around 136 degrees Fahrenheit.

The process drops the alloy printing ink onto a liquid phase cooling fluid via an injection needle, thus allowing them to create three-dimensional structures by controlling the temperature field and flow field of the cooling fluid.

Jing and Wang say nearly any metal with a low melting point – around 300°C or less – can be used as long as an appropriate cooling liquid is applied. They add that ink materials can be based on gallium, bismuth or indium.

The work shows that electromechanical systems using conductive liquid metal can also be used with nonmetal materials like various plastics to build 3D, functional devices.

Using this technique, the research teams say the digital 3D models are built on the bottom of a sort of trough which holds the cooling fluid. The cooling fluid itself can be a mixture of water, ethanol or a variety of other compatible liquids.

This work was funded in part by the Key Research Program of the Chinese Academy of Sciences.