Abstract: Metal microneedle arrays are versatile substrates for droplet-like condensation-enhanced surfaces, which are widely used in desert water harvesting, seawater desalination, and efficient heat transfer. However, the elongated conical structure and extremely small size of the microneedle body led to the existing machining process failing to realize its efficient fabrication. Thus, according to the plastic metal unit chip forming principle, a new ploughing extrusion-cutting (PE-C) method for efficient manufacturing microneedle arrays is proposed, and the machining parameters and forming mechanism are comprehensively analyzed. Results show that forming ability of microneedle arrays is negatively correlated with the relative ploughing-cutting depth t_pd and tool rake angle γ_c, and positively correlated with the ploughing depth t_p. The forward PE divided the cut layer into separation and forming layers. The separation layer is used to produce a continuous strip at the bottom of microneedle arrays. The forming layer underwent a large plastic “lamination and conductive cracking” process, producing microneedle units with a circular cross-section. In conclusion, PE-C could prepare a stiff and slender microneedle structure by regulating processing parameters, which was a simple and feasible method for efficiently fabricating microneedle arrays.

Key words: ploughing extrusion-cutting, microneedle array structure, chip forming, efficient manufacturing, surface structure