The use of printed circuit boards (PCBs) has become essential in manufacturing parts with electronic functions. However, the placement of PCBs inside a product requires special plates or fixtures that need to be separately designed, fabricated, and assembled. In addition, PCB manufacturing generally utilizes various toxic metals and etchants. Thus, there is a need to address the issues of space, cost, and environmental toxicity inherent in PCBs. This paper proposes a novel method of fabricating PCB-free part with electronic circuits in a set using the casing or exterior of a product. This process enables the manufacturing of a type of molded interconnect device without conventional molding technologies by directly forming conductive circuits on the side or back of 3D-printed substrates using selective electroless plating. For 3D printing of the product structure, this study uses substrates made of polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS), which are commonly used in the popular material-extrusion 3D printing technology. As ABS and PLA have different chemical properties, the region to be plated with the electrical circuit is fabricated using ABS, whereas the remaining substrate is fabricated using PLA. ABS was chemically treated to allow electroless plating. A process for forming 3D circuits was developed and evaluated by selective electroless plating of the areas of the substrate requiring circuitry. To verify the applicability of the proposed process, circuits and integrated parts used in the industry were redesigned into a single component and fabricated by applying the proposed process. The results demonstrate that the proposed process has good practical applicability. Furthermore, it has low environmental toxicity with low requirements for material consumption and processing energy.

在制造具有电子功能的零件时，印刷电路板（PCB）的使用已变得至关重要。但是，将PCB放置在产品内部需要特殊的板或固定装置，这些板或固定装置需要分别设计，制造和组装。另外，PCB制造通常利用各种有毒金属和蚀刻剂。因此，需要解决PCB固有的空间，成本和环境毒性问题。本文提出了一种新颖的方法，该方法使用产品的外壳或外部在一组中制造带有电子电路的无PCB零件。通过使用选择性化学镀在3D打印的基板的侧面或背面直接形成导电电路，该工艺无需传统的成型技术就能制造出一种类型的成型互连器件。对于产品结构的3D打印，本研究使用由聚乳酸（PLA）和丙烯腈丁二烯苯乙烯（ABS）制成的基材，这些基材通常用于流行的材料挤出3D打印技术中。由于ABS和PLA具有不同的化学性质，因此要使用ABS制作要电镀电路的区域，而其余的基板则使用PLA制作。ABS经过化学处理，可以进行化学镀。通过选择性地化学镀覆需要电路的区域来开发和评估形成3D电路的工艺。为了验证所提出的方法的适用性，将行业中使用的电路和集成零件重新设计为单个组件，并通过应用所提出的方法进行制造。结果表明，该方法具有良好的实用性。此外，它具有低环境毒性，对材料消耗和加工能量的要求低。