Multi-material additive manufacturing through electrostatic metal powder attraction and laser-induced forward transfer

The possibility to produce multi-materials and functionally graded materials opens new opportunities within material development, not only to explore new possibilities for combinations of different materials, but also to develop entirely new materials. Materials that are customized for individual applications and purposes down to the level of a single product. Here a process is described, where applied voltage onto a machine element results in an electrostatic attraction of powder. The machine element has certain electrical abilities and is transparent to certain wavelengths of light. The powder attraction is relatively uncomplex using a high DC voltage source with low amperage. The attracted powder on the machine element is selectively transferred to the workpiece by using laser-induced forward transfer (LIFT). The final goal is to melt the transferred powder onto the workpiece with the laser from LIFT. This part of the process and its developments are discussed in detail. Thereby, the powder is selectively added to the workpiece surface, making it possible to apply a combination of different materials without contaminating the powder stock.