While it's possible to 3D-print plastic or metal items, printing single items made of both materials is still quite difficult. Scientists have developed a new method of doing so, however, that could lead to increased production of fully functional 3D-printed electronics.
First of all, it is already possible to coat 3D-printed plastic items with metal.
Doing so involves submerging the object in a solution containing palladium, which sticks to the surface of the plastic. When that item is subsequently placed in an electroless plating bath, the adhered palladium acts as a catalyst, causing metal ions that are dissolved in the bath to stick to the object. This ultimately results in a metallic coating.
According to researchers at Japan's Waseda University, though, such coatings tend to adhere to the plastic poorly, and are not uniform. Additionally, they cover the entire item, which isn't always desirable.
Led by Prof. Shinjiro Umezo, the scientists developed a new 3D printing system that builds objects up by depositing layers of material from two nozzles. One of them extrudes melted ABS plastic, while the other extrudes melted ABS mixed with palladium. The pure ABS is used for parts of the object that are intended to be straight plastic, while the ABS/palladium is used for areas that will be metal-coated.
Once the printed item has cooled and hardened, it's placed in the previously mentioned electroless plating bath. In this case, however, the metal coating only forms on the areas printed from the ABS/palladium mixture. According to the researchers, the coating is uniform in quality, and adheres to the plastic strongly.
As an added bonus, unlike the traditional coating method, the new printing system doesn't require the surface of the plastic to first be roughened with toxic chemicals. And as an added bonus, the technology can be retrofitted into existing fused filament fabrication 3D printers.
The research is described in a paper that was recently published in the journal Additive Manufacturing.
Source: Waseda University
