Nowadays, a challenging scenario involving additive manufacturing (AM), or 3D printing, relates to concerns on the manufacturing of electronic devices. In particular, the possibility of using fused filament fabrication (FFF) technology, which is well known for being very widespread and inexpensive, to fabricate structures with embedded sensing elements, is really appealing. Several researchers in this field have highlighted the high electrical resistance values and variability in 3D-printed strain sensors made via FFF. It is important to find a way to minimize the electrical resistance and variability among strain sensors printed under the same conditions for several reasons, such as reducing the measurement noise and better balancing four 3D-printed strain gauges connected to form a Wheatstone bridge to obtain better measurements. In this study, a design of experiment (DoE) on 3D-printed strain gauges, studying the relevance of printing and design parameters, was performed. Three different commercial conductive materials were analyzed, including a total of 105 printed samples. The output of this study is a combination of parameters which allow both the electrical resistance and variability to be minimized; in particular, it was discovered that the “welding effect” due to the layer height and printing orientation is responsible for high values of resistance and variability. After the optimization of printing and design parameters, further experiments were performed to characterize the sensitivity of each specimen to mechanical and thermal stresses, highlighting an interesting aspect. A sensible variation of the electrical resistance at room temperature was observed, even if no stress was applied to the specimen, suggesting the potential of exploiting these materials for the 3D printing of highly sensitive temperature sensors.

如今，涉及增材制造（AM）或3D打印的具有挑战性的场景涉及对电子设备制造的关注。特别地，使用以非常普遍和廉价的众所周知的熔融长丝制造（FFF）技术来制造具有嵌入式感测元件的结构的可能性确实吸引人。该领域的一些研究人员强调了通过FFF制造的3D打印应变传感器的高电阻值和可变性。重要的是，要找到一种方法来使在相同条件下打印的应变传感器之间的电阻和可变性最小化，这有几个原因，例如，降低测量噪声并更好地平衡连接形成惠斯通电桥的四个3D打印应变仪，以获得更好的效果。测量。在这个研究中，在3D打印的应变仪上进行了实验设计（DoE），研究了打印和设计参数的相关性。分析了三种不同的商业导电材料，包括总共105个印刷样品。这项研究的输出是参数的组合，可以使电阻和可变性都最小化。特别是，发现由于层高和印刷方向而产生的“焊接效果”是导致高电阻和可变性的原因。在优化印刷和设计参数之后，进行了进一步的实验，以表征每个样品对机械应力和热应力的敏感性，突出了一个有趣的方面。在室温下观察到电阻的明显变化，