Researchers Develop Multi-Material DLP Method For Plastic-Metal Composites

Both plastic and metal are key materials within many 3D printing processes and applications. When combined to make plastic-metal composites, the properties are modified to apply to a number of fields as the final product has metal and plastic integrated within its structure. However, current methods to do this are expensive. Researchers at Waseda University, Japan, and Nanyang Technological University (NTU), have therefore developed a process for the fabrication of these structures, known as multi-material DLP additive manufacturing or MM-DLP3DP.

The researchers performed a multi-step process. To start with, they prepared active precursors: that is, the chemical which was transformed into a different chemical. They used NH4Cl in 50 mL of deionized water, to which 270 mg of PdCl2 was added. Once fully prepared, they mixed this with one of the light-curable resins. The palladium ions allow the metal particles in solution to be deposited in ELP: this essentially means that the metal ions settle onto a pre-existing surface to form the metal pattern. In short, this first step consisted of the creation of modified resins for the ELP process.

Examples of plated parts made with multi-material DLP 3D printing. (Photo credit: Waseda University)

Next the MM-DLP3DP process was used to make micro-structures of nested regions of the resin or active precursor together. Finally, they plated the materials and added 3D metal patterns with the use of ELP. To demonstrate the usefulness of this technology, they manufactured a 3D circuit with a double-sided structure which was connected by a through-hole, and also a series of sensors which can be integrated with the product being measured (a general example would be a thermometer manufactured with an integrated temperature detector). As they showed, MM-DLP4DP has ‘higher resolution and thus allows the construction of microstructured surfaces with special functions’ when compared to multiple-nozzle printing.