A 3D thermo-mechanical finite element model was developed to study the effect of the laser jump speed on the temperature distribution and thermal stress in laser powder bed fusion (LPBF) of Ti6Al4V alloy. Gradient grid and gradient time step were used to further improve solution efficiency. It was found that the temperature of the scanned region rapidly increased as the laser jump speed increased from 100 mm/s to 1000 mm/s. The temperature distribution reached a stable state when the laser jump speed was above 5000 mm/s. The pre-heat peak, the heat peak and the post-heat peak increased with the laser jump speed. The effect of the laser jump speed on the post-heat peak was greater than the pre-heat peak. Compared with the long scan track, the thermal stress distribution varies more sharply with the laser jump speed when using the short scan track. The influence of the laser jump speed on the stress perpendicular to the scan direction was greater than that along the scan direction, whether in a short scan track or in a long scan track. To reduce the residual stress, the length of the scan track should be reduced while the laser jump speed should be increased as much as possible to make the post-heat peak close to the fusion temperature of the material. The simulated results were well validated by the experimental data. The findings of this research help to reduce the thermal stress in laser powder bed fusion.

开发了 3D 热机械有限元模型，以研究激光跳跃速度对 Ti6Al4V 合金激光粉末床融合 (LPBF) 温度分布和热应力的影响。渐变网格和渐变时间步被用来进一步提高求解效率。发现随着激光跳跃速度从 100 mm/s 增加到 1000 mm/s，扫描区域的温度迅速升高。当激光跳跃速度大于 5000 mm/s 时，温度分布达到稳定状态。预热峰，热峰和后热峰随着激光跳跃速度的增加而增加。激光跳跃速度对后热峰的影响大于预热峰。与长扫描轨道相比，使用短扫描轨道时，热应力分布随激光跳跃速度的变化更加剧烈。无论是短扫描轨迹还是长扫描轨迹，激光跳跃速度对垂直于扫描方向的应力的影响都大于沿扫描方向的应力。为减小残余应力，应减少扫描轨迹长度，同时尽可能提高激光跳跃速度，使后热峰接近材料的熔化温度。实验数据很好地验证了模拟结果。这项研究的结果有助于降低激光粉末床融合过程中的热应力。应减少扫描轨迹的长度，同时尽可能提高激光跳跃速度，使后热峰接近材料的熔化温度。实验数据很好地验证了模拟结果。这项研究的结果有助于降低激光粉末床融合过程中的热应力。应减少扫描轨迹的长度，同时尽可能提高激光跳跃速度，使后热峰接近材料的熔化温度。实验数据很好地验证了模拟结果。这项研究的结果有助于降低激光粉末床融合过程中的热应力。