Parallel multi arc directed energy deposition: New way to achieve efficient manufacturing of large-size lattice sandwich structure

Directed energy deposition-arc (DED-Arc) is gaining popularity which enables the low-cost manufacturing of meter scale large-size lattice sandwich structure (LSS). However, the limited manufacturing efficiency led to long deposition time. Local heat accumulation often led to distortion and crack. To overcome these challenges, a new manufacturing method, named as parallel multi arc directed energy deposition (PM-Arc-DED) is proposed, and a PM-Arc-DED machine tool is designed in current work. The structural layout design method of machine tool kinematic chain is proposed. The incidence matrix F and orientation matrix D_d^ij of components and kinematic pairs are established based on structural layout design method. The meter scale multi-layer LSS is fabricated by PM-Arc-DED. Through the PM-Arc-DED inclined rod deposition experiment and characterization, the real-time parameter changes of multi-arc simultaneous manufacturing, tensile properties and microstructure are analyzed, and the feasibility of PM-Arc-DED is verified. In addition, the difference between PM-Arc-DED method and single-arc method in node connection is explored in terms of the temperature field and distortion. The results show that under the premise of greatly improving the deposition efficiency (The mass of material melted per unit time) by almost one order (from 1.84 kg/h to 9.22 kg/h), the PM-Arc-DED can reduce the distortion of LSS by more than twice compared with the single-arc method. Moreover, the proposed method can also guide the design of other types of multi heat source additive manufacturing technology.