基板厚度对薄壁件GMA增材制造温度场的影响

Influence of substrate thickness on the thermal process for thin-walled part in GMA-based additive manufacturing

关键词:  GMA增材制造  基板厚度  温度场  温度梯度

Key words:  GMA-based additive manufacturing  substrate thickness  temperature field  temperature gradient

摘要:

对环形薄壁件GMA增材制造温度场进行数值模拟，采用热循环试验对计算结果进行验证，并研究基板厚度对堆积过程温度场的影响. 结果表明，基板厚度增加，熔池最高温度降低且长度减小，“拖尾”状况改善明显. 第一层中点热循环曲线上的波峰和波谷随基板厚度增加而降低，波峰差值先增大后趋于稳定，波谷差值先保持稳定再减小. 熔池轴向最大温度梯度随基板厚度增加而增大，但增量逐渐减少. 熄弧时刻，基板厚度增加，各层中点的轴向温度梯度增大，但随堆积高度增加，轴向温度梯度上升趋势明显减弱.

Abstract:

The thermal process for a circular thin-walled part in gas metal arc (GMA) based additive manufacturing is researched via numerical simulation, and the validity of the model is tested based on the thermal cycle experiment. Then, the effect of substrate thickness on the temperature field of deposition process is investigated. The results show that the maximum temperature in the molten pool decreases with the increase of the substrate thickness. The length of molten pool enlarges, and the trailing conditions improved significantly. With the increase of the substrate thickness, the peaks and trough values of the first thermal cycling curve decline gradually. The difference of peak temperature increases first, then keeps steady, whereas the difference of tough values stays stable first then decreases. The axial maximum temperature gradient near molten pool increases along with the increment of substrate thickness, but the increasing amount of temperature gradient declines. At the ending moment of deposition, the axial gradient of each middle point in deposition layers increases as the substrate thickness increases. However, with the increase of the deposition height, increasing tendency becomes weak.