## 4 Discussion  
### Finding 1: Calibration Leading to an Increase in Dimensional Stability  
The graph in Figure 12 illustrates the relationship between the machining (calibration) of the samples and the total runout deviation during the tests. It provides insights into how the machining of the samples influenced their performance during the tests in a positive way. Figure 11: Samples bonded with Eprosin—Runout and its deviation during environmental tests. Figure 10: Samples bonded with Spabond—Runout and its deviation during environmental tests. Figure 9: Samples bonded with DP 110—Runout and its deviation during environmental tests. None of the eight samples that underwent calibration turning exceeded a total runout deviation of 0.01 mm. For seven out of eight of the calibrated samples (87.5%), the deviation did not even exceed 0.005 mm. In contrast, among the noncalibrated samples, a significant portion, six out of seven (85%), exceeded the 0.01 mm tolerance at least once during environmental testing, and two of them (28.5%) exceeded the deviation of 0.025 mm at least once during testing. This suggests that calibration turning significantly improved the stability and precision of the samples. The validity of this statement can be quantitatively assessed by comparing the average maximum deviation value \(\overline{\Delta}_{max}\) of calibrated and noncalibrated samples and the average value of the final deviation \(\overline{\Delta}_{end}\) of calibrated and noncalibrated samples (Table 5). Based on these findings, it can be deduced that during calibration/machining, a significant portion of the shrinkage stress in the bonded joint is released. This stress causes a deformation resulting in a change in the total runout of the unmanned samples when subjected to thermal loading. Stress relaxation during machining can result from either mechanical or thermal loading. Therefore, it is essential to account for shrinkage stress after the adhesive has completely cured in future research aimed at addressing this issue. Additionally, the creeping behavior of the adhesives employed may be another significant factor affecting precision and dimensional stability. This finding is to some extent in line with other researchers' observations. [PERSON] et al. [41] also investigated the impact of shrinkage on high-precision bonded assemblies. Their approach involves automated active compensation for misalignment, very accurate volumetric dosing of the adhesive, and frequent measurements of the shrinkage of the adhesive. While replicating their approach was not possible in this research, the findings by [PERSON] et al. regarding changes in volumetric shrinkage of up to 5% within batches further underscore the complexity of this issue. [PERSON] et al. [69] have researched adhesive bonding with high accuracy as well. Their findings suggest that increasing the bonded gap size leads to greater adhesive shrinkage. Conversely, minimizing the gap size enhances the strength of the bonded joint [32; 33]. Achieving minimal gap sizes requires optimizing the manufacturing precision of CFRP parts. Figure 12: Deviation of total runout during the environmental tests. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample Type** & \(\overline{\Delta}_{max}\)**(mm)** & \(\overline{\Delta}_{end}\)**[mm]** & \(\frac{\overline{\Delta}_{end}}{\Delta_{max}}\cdot\textbf{100}\) \\ \hline Calibrated samples & 0.0041 & 0.0032 & 21.9\% \\ Noncalibrated samples & 0.0164 & 0.0101 & 38.4\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The average value of maximum deviation. Some adhesives, like Spabond(tm) 340 LV HT used in this study, may either require or benefit from curing at elevated temperatures. While it can cure at 21 \({}^{\circ}\)C for 28 days, accelerating the curing process by applying higher temperatures can result in increased tensile strength, a higher glass transition temperature, and reduced volumetric shrinkage [67]. [PERSON] et al. study a similar phenomenon with nonconductive adhesives.