Purpose

Additive manufacturing (AM) of thermoplastic polymers for powder bed fusion processes typically requires each layer to be fused before the next can be deposited. The purpose of this paper is to present a volumetric AM method in the form of deeply penetrating radio frequency (RF) radiation to improve the speed of the process and the mechanical properties of the polymer parts.

Design/methodology/approach

The focus of this study was to demonstrate the volumetric fusion of composite mixtures containing polyamide (nylon) 12 and graphite powders using RF radiation as the sole energy source to establish the feasibility of a volumetric AM process for thermoplastic polymers. Impedance spectroscopy was used to measure the dielectric properties of the mixtures as a function of increasing graphite content and identify the percolation limit. The mixtures were then tested in a parallel plate electrode chamber connected to an RF generator to measure the heating effectiveness of different graphite concentrations. During the experiments, the surface temperature of the doped mixtures was monitored.

Findings

Nylon 12 mixtures containing between 10% and 60% graphite by weight were created, and the loss tangent reached a maximum of 35%. Selective RF heating was shown through the formation of fused composite parts within the powder beds.

Originality/value

The feasibility of a novel volumetric AM process for thermoplastic polymers was demonstrated in this study, in which RF radiation was used to achieve fusion in graphite-doped nylon powders.

中文翻译：

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石墨掺杂尼龙 12 粉末与射频辐射的体积融合

目的

用于粉末床熔合工艺的热塑性聚合物的增材制造 (AM) 通常需要在沉积下一层之前先熔合每一层。本文的目的是提出一种以深度穿透射频 (RF) 辐射形式的体积 AM 方法，以提高工艺速度和聚合物部件的机械性能。

设计/方法/方法

本研究的重点是展示使用射频辐射作为唯一能源的含有聚酰胺（尼龙）12 和石墨粉末的复合混合物的体积融合，以确定热塑性聚合物体积增材制造工艺的可行性。阻抗谱被用来测量混合物的介电性能作为增加石墨含量的函数，并确定渗透极限。然后在连接到射频发生器的平行板电极室中测试混合物，以测量不同石墨浓度的加热效果。在实验期间，监测掺杂混合物的表面温度。

发现

生成了按重量计含有 10% 到 60% 石墨的尼龙 12 混合物，损耗角正切达到最大值 35%。选择性射频加热通过在粉末床内形成熔融复合材料部件来显示。

原创性/价值

本研究证明了一种用于热塑性聚合物的新型体积增材制造工艺的可行性，其中射频辐射用于实现石墨掺杂尼龙粉末的融合。