Bead parameterization of desktop and room-scale material extrusion additive manufacturing: How print speed and thermal properties affect heat transfer
Bead parameterization of desktop and room-scale material extrusion additive manufacturing: How print speed and thermal properties affect heat transfer
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DOI：
10.1016/j.addma.2020.101239
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发表时间：
2020-08-01
影响因子：
11
通讯作者：
Peterson, Amy M.
中科院分区：
文献类型：
--
作者：
D'Amico, Tone;Peterson, Amy M.
材料挤出（MatEx）增材制造的规模从桌面规模的熔丝制造（FFF）到室内规模的大面积增材制造（BAAM）。FFF和BAAM的工作原理是相似的-聚合物原料被加热至熔融，然后通过逐层增材制造挤出形成三维零件。然而，FFF和BAAM的尺度有很大的不同，这导致了这些热驱动过程的热行为的关键差异。本研究采用有限元热模型比较了FFF和BAAM中的传热。参数化是在MatEx的桌面和房间规模上跨材料属性、层数和打印速度执行的。BAAM比FFF在更长的时间内保持更热，这有利于层间扩散和焊缝形成，但也可能导致塌陷或下垂。热扩散率的变化影响FFF比BAAM，与FFF表现出局部最大焊接时间在ABS的热扩散率。在所有情况下，焊接时间长于弛豫时间，表明聚合物重新取向和相互扩散是可能的。对于BAAM来说，挤出珠粒中心的温度和热历史与珠粒表面有很大差异，这对过程监控、性能预测和零件性能具有重要影响。
Material extrusion (MatEx) additive manufacturing ranges in size from the desktop scale fused filament fabrication (FFF) to the room scale big area additive manufacturing (BAAM). The principles of how FFF and BAAM operate are similar - polymer feedstocks are heated until molten and then extruded to form three-dimensional parts through layer-by-layer additive manufacturing. However, the scales of FFF and BAAM differ substantially, which leads to critical differences in thermal behavior for these thermally-driven processes. This study compares heat transfer in FFF and BAAM using finite element thermal modeling. Parameterization is performed across material properties, layer number, and print speed at the desktop and room scale for MatEx. BAAM stays hotter than FFF for a longer period of time, which facilitates interlayer diffusion and weld formation, but can also lead to slumping or sagging. Changes in thermal diffusivity affect FFF more than BAAM, with FFF exhibiting a local maximum in weld time at the thermal diffusivity of ABS. In all cases, weld time is longer than relaxation time, indicating that polymer reorientation and interdiffusion is possible. For BAAM, the temperature and thermal history of the center of an extruded bead differs greatly from the surface of the bead, which has important implications for process monitoring, property prediction, and part performance.