Project Profile

Goals of the project

We are developing a rapid-prototyping process for producing circuit boards using liquid metal. This will allow a circuit board to be quickly manufactured onsite for prototyping or urgent repairs. The proposed circuit boards will be patterned by photolithography, and liquid metals will be used to form the circuit traces, in a process that will take only a few minutes. The materials in the circuit board can be recovered for reuse to reduce waste and allow for circuit board production with limited resources. 

Nature of the Collaboration

A. Ohta provided microfluidic and fabrication advice. W. Shiroma provided circuit fabrication and general advice. M. Inouye conceived of the idea and carried out the experiments and fabrication.



Circuit design


EagleCAD circuit design software, laser printer for transparency masks


Overall idea was conceived, and methods for realizing the overall idea were discussed. Prototypes were created to test the various methods. 


1. Creation of a simple LED-resistor circuit using surface-mount components

2. Creation of a simple LED-resistor circuit using through-hole components

Challenges encountered

The rapid molding of the channels for the liquid metal presented the greatest difficulty. Usable channels were achieved by selecting the right photopolymer, although this still needs improvement.

Major outcomes

Simple circuits can be created using printed photomasks and liquid metal. The liquid metal can be recovered and reused in other circuits.

Innovations, impact and successes

The concept was proved, although more work is needed to develop this into a robust rapid prototyping method for complex circuits. If this can be realized, this can aid makers as they go through the prototyping process when creating electrical circuits.