Abstract

This work aimed at introducing and exploring the potential of a thermal management technique, named as near-immersion active cooling (NIAC), to mitigate heat accumulation in Wire + Arc Additive Manufacturing (WAAM). According to this technique concept, the preform is deposited inside a work tank that is filled with water, whose level rises while the metal layers are deposited. For validation of the NIAC technique, Al5Mg single-pass multi-layer linear walls were deposited by the CMT® process under different thermal management approaches. During depositions, the temperature history of the preforms was measured. Porosity was assessed as a means of analyzing the potential negative effect of the water cooling in the NIAC technique. The preform geometry and mechanical properties were also assessed. The results showed that the NIAC technique was efficient to mitigate heat accumulation in WAAM of aluminum. The temperature of the preforms was kept low independently of its height. There was no measurable increase in porosity with the water cooling. In addition, the wall width was virtually constant, and the anisotropy of mechanical properties tends to be reduced, characterizing a preform quality improvement. Thus, the NIAC technique offers an efficient and low-cost thermal management approach to mitigate heat accumulation in WAAM and, consequently, also to cope with the deleterious issues related to such emerging alternative of additive manufacturing.

中文翻译：

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减少WAAM中热量积聚的主动冷却技术的概念和验证

摘要

这项工作旨在介绍和探索一种称为近浸式主动冷却（NIAC）的热管理技术的潜力，以减轻导线+电弧增材制造（WAAM）中的热量积聚。根据该技术概念，预成型件沉积在充满水的工作槽内，水在沉积金属层时水位上升。为了验证NIAC技术，通过CMT®工艺在不同的热管理方法下沉积了Al5Mg单程多层线性墙。在沉积期间，测量预成型件的温度历史。评估孔隙率是分析NIAC技术中水冷却的潜在负面影响的一种方法。还评估了瓶坯的几何形状和机械性能。结果表明，NIAC技术可有效缓解铝WAAM中的热量积聚。瓶坯的温度与瓶坯高度无关地保持较低。随着水冷却，孔隙率没有可测量的增加。另外，壁宽度实际上是恒定的，并且机械性能的各向异性趋于减小，这是预成型坯质量提高的特征。因此，NIAC技术提供了一种高效且低成本的热管理方法，以减轻WAAM中的热量积聚，从而也可以解决与这种新兴的增材制造替代方案相关的有害问题。另外，壁宽度实际上是恒定的，并且机械性能的各向异性趋于减小，这是预成型坯质量提高的特征。因此，NIAC技术提供了一种高效且低成本的热管理方法，以减轻WAAM中的热量积聚，从而也可以解决与这种新兴的增材制造替代方案相关的有害问题。另外，壁宽度实际上是恒定的，并且机械性能的各向异性趋于减小，这是预成型坯质量提高的特征。因此，NIAC技术提供了一种高效且低成本的热管理方法，以减轻WAAM中的热量积聚，从而也可以解决与这种新兴的增材制造替代方案相关的有害问题。