Waseda University develops novel 3D printing method for complex metal-plastic composite structures

Researchers from Japan and Singapore developed a 3D printing process that allows the creation of complex 3D metal-plastic composite structures.

According to Waseda University In recent years, research has intensified in the area of 3D printing metal patterns on parts made of plastic.

Potential applications of 3D metal/plastic composite structures include smart electronics, quantum computing, micro-nanosensing devices, internet-of–things (IoT), and quantum computing. These devices have greater design freedom than other types, can be more complicated, have complex geometry and have smaller sizes. Waseda states that the current methods for fabricating such parts are costly and complex.

A multi-material digital light processing (3D printing) process was developed by researchers from Japan and Singapore. 

Lead authors Professor Shinjiro umezu, Mr. Kewei song from Waseda University und Professor Hirokata Satomo from Nanyang Technological University, Singapore said: “Robots and IoT devices are evolving at a lightning pace. Therefore, technology must improve to produce them. Even though 3D circuits are possible with current technology, stacking flatcircuits is still a subject of intense research. We wanted to address this issue to create highly functional devices to promote the progress and development of human society.”

The MM-DLP3DP procedure begins with the preparation active precursors. These are chemicals that can be converted to the desired chemical by 3D printing. However, the desired chemical cannot be printed directly. This process involves the addition of palladium ions to light-cured resins in order to prepare active precursors.

To promote electroless plating (ELP), the palladium ions were added. This is a process which describes the auto-catalytic removal of metal ions from an aqueous solution in order to form a metal coated. Next is the fabrication of microstructures that contain nested regions or active precursors.

The materials are then directly plat and 3D patterns of metal are added by ELP.

Waseda University stated that the team created a range of parts with complex topologies to show the capabilities of the proposed method. These parts were complex with multiple-material nesting layers. The smallest hollow structure was 40µm in size.

The metal patterns were ‘very specific’ and could be precisely controlled according to Waseda. The team also created 3D circuit boards using complex metal topologies. They included an LED stereo circuit made of nickel and a double-sided 3D with copper.

“Using the MM-DLP3DP process, arbitrarily complex metal-plastic 3D parts having specific metal patterns can be fabricated. Using active precursors to selectively induce metal deposition can result in higher quality metal coatings. Together, these factors can contribute to the development of highly integrated and customisable 3D microelectronics,” said Umezu, Song, and Sato.

Waseda University claims that the new manufacturing technology promises to revolutionize the manufacture of circuits. It can also be applied in a variety of technologies. Some of the possible applications include 3D electronics, metal hollow electrodes, metamaterials and flexible wearing devices.

In November, a team of researchers at Waseda University proposed a design strategy to address the challenge of deformation caused by residual stress in metal additive manufacturing fabrication technology.

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