## 2 Materials and Methods
The trigger points are color coded in Figure 5 to show the progression and number of triggers on a per layer basis. Two walls were printed for this study. The first wall contained step changes in only the second of two beads per layer, and the step changes commanded the melt pool size 25% higher than nominal. The second wall contained step changes in both beads, and the melt pool size was commanded 37.5% higher than nominal. This experimental setup allowed for a comparison of melt pool size and laser power response across beads and across magnitudes of step changes. This is summarized in Table 3. The nominal melt pool size was determined through testing in which deposits were made with nominal parameters while only monitoring with the thermal camera. The measured melt pool size then subsequently became the setpoint for control. The increased melt pool size was selected to produce a large increase in size while still maintaining process stability based on significant experience with the deposition parameters. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Value** & **Units** \\ \hline Initial distance & 10 & mm \\ Distance increment & 1 & mm \\ Wire feed increment & \(-\)2.2 & \% \\ Maximum layer & 20 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Bead termination routine parameters. Figure 5: Generalized workflow for oak leaf trigger point generation. From Left to right: Original sketch, layered geometry, final trigger points. The stability concern arises from the fact that if laser power increases too much, the wire feedstock can begin to transfer in droplet form, at which point it is difficult, if not impossible, to measure the melt pool size. Additionally, a command for a larger melt pool size results in an increase in laser power, which, without a corresponding increase in wire feed rate, results in a wider and shorter bead profile. In theory, if this behavior happened repeatedly on a layer-by-layer basis, a height deficit could propagate and result in a major defect. The previously discussed layer height control algorithm counteracts this effect through interlayer scanning and modification of the parameters of the following layer. While the melt pool size controller and the layer height controller operate concurrently, the systems have no a priori knowledge of the other's actions, meaning that interesting interactions between the systems are certainly possible. Characterizing these interactions was not within the scope of this work, but a measurement of the final wall geometry served as an indicator of the degree to which the layer height control system accomplished its task. The response of the melt pool size control system was characterized by examining the melt pool size and laser power behavior at the selected locations. The scaled melt pool size data was overlaid with robot position feedback data to generate a visualization of melt pool size for an entire half of a wall. The melt pool response time was specifically examined in the region of the oak leaf stem in Wall 2, which contained the higher magnitude step changes. The stem contained a range of steps that were relatively short in duration, an ideal scenario for evaluating the minimum duration for which the melt pool setpoint could actually be achieved, i.e., the process resolution. A further examination of melt pool bandwidth was not within the scope of this work, but additional information has been presented in the literature on the melt pool response for this specific laser-wire DED process [12]. Final part geometry was characterized via scanning with a FaroArm scanner (FARO, Lake Mary, FL, USA), which generated virtual, 3D representations of the printed components. This allowed for a comparison of the printed geometry against an ideal representation of a flat wall with no embossed, secondary geometry. The magnitude of oak leaf embossing could be determined and compared across test cases.