## 4 Discussion
### Interpretation of Main Effects  
The locating scheme, factor E, exhibited an extremely significant effect on displacement after welding with close to zero \(p\)-Values, Table 4. Among the three levels, the near-optimal (N-O) solution derived from the initial screening's lowest displacements, followed by a  
Figure 8: RMS of the displacements for the reference assemblies with the N-O parameter configurations, (**a**) Reference Assembly I, (**b**) Reference Assembly II.  
Figure 7: Significant factors plot for Assembly II, (**a**) Locating scheme, (**b**) Welding sequence, (**c**) Weld path F direction, (**d**) Weld path G direction, (**e**) Interaction between locating scheme and sequence, (**f**) Interaction between sequence and weld F direction.  
solution close to the mean value derived from the screening, resulted in lower displacement considering the welding sequence and direction of the welds. The real significance of the locating scheme on the outcome of the welding is prominent in a sensitive positioning system, which results in higher displacements, as visualized in Figures 6a and 7a. From the screening of the locating systems, it can also be seen that near-optimal solutions have a value closer to the mean of the displacements achieved with different locating scheme solutions, while a sensitive, as opposed to a robust, solution results in higher displacements, Figure 3. This analysis, in line with prior research on fixturing, indicates that a robust locating scheme can effectively minimize displacement by ensuring better alignment and stability during the welding process. The influence of locating schemes is consistent with prior studies highlighting the importance of fixture design and workpiece stability in reducing welding-induced distortions.  
The welding sequence parameter also significantly influences displacement with close to zero \(p\)-Values, Table 4. The identification of the optimal welding sequence with a fixed locating scheme results in lower displacements. However, changing the locating scheme also changes the welding conditions, which means that an optimal welding sequence with one locating scheme does not necessarily result in lower displacements for all locating schemes. This behavior can be clearly seen in Figures 6b and 7b for both assemblies. This suggests that the order in which welding paths are executed needs to be optimized for a fixed locating scheme, which often occurs in practice. The welding sequence significantly influences heat distribution and residual stress minimization, thereby reducing overall displacement.  
For the weld path direction, changing the forward and backward weld passes did not result in high variability in the experiments performed for Assembly I. The maximum range of displacement achieved by changing the path directions and keeping the locating scheme and the welding sequences constant was 0.094 mm. However, in Assembly II, where the weld was performed along a curvature, the path direction is shown to have significance. In Assembly II, the initial weld path F is shown to result in lower displacement when welded in the backward direction, opposite to what is shown in Figure 2. Furthermore, with the N-I locating scheme and the N-I welding sequence, changing the path direction resulted in a range of 0.516 mm. This result specifies that with sensitive locating schemes and N-I welding sequences, the significance of the weld path direction increases. Therefore, the optimization of displacements with respect to weld path direction, given the specified condition, will result in higher-quality improvements.