Chang Tammy, Mukherjee Saptarshi, Watkins Nicholas N, Stobbe David M, Mays Owen, Baluyot Emer V, Pascall Andrew J, Tringe Joseph W
Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA.
Sci Rep. 2020 Dec 18;10(1):22325. doi: 10.1038/s41598-020-79266-2.
This article presents a millimeter-wave diagnostic for the in-situ monitoring of liquid metal jetting additive manufacturing systems. The diagnostic leverages a T-junction waveguide device to monitor impedance changes due to jetted metal droplets in real time. An analytical formulation for the time-domain T-junction operation is presented and supported with a quasi-static full-wave electromagnetic simulation model. The approach is evaluated experimentally with metallic spheres of known diameters ranging from 0.79 to 3.18 mm. It is then demonstrated in a custom drop-on-demand liquid metal jetting system where effective droplet diameters ranging from 0.8 to 1.6 mm are detected. Experimental results demonstrate that this approach can provide information about droplet size, timing, and motion by monitoring a single parameter, the reflection coefficient amplitude at the input port. These results show the promise of the impedance diagnostic as a reliable in-situ characterization method for metal droplets in an advanced manufacturing system.
本文介绍了一种用于液态金属喷射增材制造系统原位监测的毫米波诊断方法。该诊断方法利用一个T型结波导装置实时监测由于喷射金属液滴引起的阻抗变化。给出了时域T型结操作的解析公式，并辅以准静态全波电磁仿真模型。该方法通过使用直径范围从0.79到3.18毫米的已知金属球体进行了实验评估。然后在一个定制的按需滴注液态金属喷射系统中进行了演示，在该系统中检测到有效液滴直径范围为0.8到1.6毫米。实验结果表明，该方法可以通过监测单个参数（输入端口的反射系数幅度）来提供有关液滴大小、时间和运动的信息。这些结果表明了阻抗诊断作为先进制造系统中金属液滴可靠原位表征方法的前景。
