In this study, a 3-D dispensing method for nonconductive and conductive adhesives is introduced that allows for direct electrical functionalization of the printed part during the printing process. The experimental work’s focus lies on the analysis of the embedding of conductive tracks within nonconductive housings. Two different construction strategies have been analyzed for printing tracks in both xy - and $z$ -directions. For all variants, initial feasibility tests were performed that successfully validated the general applicability of these techniques. As dissimilar materials are involved in the process, a micrograph analysis was used to investigate possible negative effects within the transitional areas. Although prototypical parts can be built easily with additive manufacturing methods, the lack of knowledge about the long-term robustness is often the limiting factor to end-use applications. Accelerated life tests in the form of thermal shock and humidity testing were performed to investigate this issue. The tests demonstrate good long-term behavior for two of four adhesives. The obtained results show that the proposed method and process variants are capable of producing electronically functional parts, provided a careful material selection has been performed. Furthermore, several design rules concerning the transitional area could be derived.

中文翻译：

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使用3-D点胶的嵌入式电路混合增材制造

在这项研究中，引入了一种用于非导电和导电粘合剂的3-D分配方法，该方法允许在打印过程中直接对打印部件进行电气功能化。实验工作的重点在于分析导电迹线在非导电外壳中的嵌入。分析了两种不同的施工策略，以在两种情况下进行印刷y - 和 $ z $ -方向。对于所有变体，都进行了初步的可行性测试，成功地验证了这些技术的普遍适用性。由于该过程涉及不同的材料，因此使用了显微照片分析来研究过渡区域内可能产生的负面影响。尽管可以通过增材制造方法轻松制造原型零件，但是缺乏对长期耐用性的了解通常是最终用途应用的限制因素。进行了热冲击和湿度测试形式的加速寿命测试来调查此问题。该测试表明四种粘合剂中的两种具有良好的长期性能。获得的结果表明，所提出的方法和工艺变型能够生产电子功能部件，如果已经进行了仔细的材料选择。此外，可以得出有关过渡区域的一些设计规则。