Transfer characteristics for laser-induced forward transfer of stainless steel particle

Abstract

Additive manufacturing (AM) holds great development potential in several applications. In particular, the fabrication of metal parts has been rapidly developing as an industry recently. In such applications, a powder feeder with low material loss is required to ensure effective material usage. Thus, the manufacturing process using laser-induced forward transfer (LIFT) is attractive as a candidate for advances in powder feeder technology. We show that stainless steel particle with diameters of 26 to 53 μm can be transferred via the particle LIFT process; the transfer of particles started at a peak fluence of ∼0.05 J cm − 2 (26- and 36-μm diameters) and ∼0.15 J cm − 2 (53-μm diameter), and the particles were fully transferred (i.e., the probability of transfer reaches unity) at a peak fluence of 0.2 (26 μm), 0.4 (39 μm), and 0.5 J cm − 2 (53 μm). The initial velocity, v0, at which the particle leaves the substrate increased proportionally with the increase in peak fluence. When the point of irradiation of the laser beam was displaced from the contact point of the particle on the substrate, the particle was transferred with a transfer angle (i.e., not vertically). These results demonstrate the possibility of transferring metal particles via the LIFT process. To use this technology for AM, the laser power should be adjusted to control the transfer angle of the particle.