关键词: DMLS, 多层烧结模拟, 瞬态温度场, 单元生死技术

Abstract:

In order to acquire the heating-cooling process of laser molten pool and the mutual effect of sintering layers in multi-layer powder sintering, factors such as heat conduction, heat radiation, heat convecting and changeable thermophysical property parameters were taken into account comprehensively, the 3D transient state FEM of the temperature field of multi-layer thin-wall metal parts formed by DMLS was established based on ANSYS. The APDL (ANSYS Parametric Design Language) was used to carry out thermal resource moving and the technique of birth/death for element was used to simulate the process of material addition. The simulation results show that with the present process parameters ,sintering depth is over 0.15mm,sintering width is about 0.61mm, sintered part is jointed tight with substrate and within the inter-layers; the thermal gradient along z direction within the sintered part is absolutely predominant compared with that along x direction, so heat dissipates mainly along z direction during cooling process. At last the sintering experiment was carried out, it indicates that experimental result agrees with the previous simulation result well.

Key words: direct metal laser sintering (DMLS), multi-layer sintering simulation, transient temperature field, technique of birth/death for element