## 3 Results  
### In situ Temperature Measurements  
For the six pattern case studies, temperature measurements were performed at five locations, and a total of 30 locations were measured. Of the 30 measurements, four of the trials failed due to the poor contact of the thermocouple, but the temperature was successfully measured for the remaining 26 points, and the temperature distribution according to each pattern was analyzed (Table 3). The corresponding temperature histories for each pattern are provided in Figure 7.  
In situ temperature measurements show that the temperature trends at each point are significantly different depending on the long raster pattern and the short raster pattern. These results are especially evident in TC2 (Figure 8b), which is the center location of the substrate back side. In the case of the short raster pattern, the maximum temperature gradually increases with rise and fall, whereas in the case of the long raster pattern, the maximum temperature gradient increases with a rapid temperature gradient and the temperature tends to decrease with a rapid temperature gradient in each layer. Figure 8: In situ temperature history of each thermocouple for all patterns: (**a**) Thermocouple 1 temperature history; (**b**) Thermocouple 2 temperature history; (**c**) Thermocouple 3 temperature history; (**d**) Thermocouple 4 temperature history; (**e**) Thermocouple 5 temperature history. \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & **TC 1** & **TC 2** & **TC 3** & **TC 4** & **TC 5** \\ \hline Pattern 1 & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ Pattern 2 & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ Pattern 3 & \(\bigcirc\) & \(\bigcirc\) & \(\bigtimes\) & \(\bigtimes\) & \(\bigcirc\) \\ Pattern 4 & \(\bigcirc\) & \(\bigcirc\) & \(\bigtimes\) & \(\bigcirc\) & \(\bigcirc\) \\ Pattern 5 & \(\bigtimes\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ Pattern 6 & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Temperature measurement success/failure results at each location. Maximum temperature recorded in thermocouple 2 for each layer and temperature at the end of each layer for pattern 1 and pattern 2 are shown in Figure 9. From this result, even if the same heat input is applied to the same area for the same time, the temperature distribution and maximum temperature generated according to the tool path are different. In both patterns considering the tool path, the temperature rises when the distance between the temperature measurement point and the heat source decreases, and the temperature decreases when the distance increases. However, the temperature gradient in pattern 2 is found to be steeper than in pattern 1, and the highest temperature in thermocouple 2 is also higher in pattern 2. Furthermore, when comparing the highest recorded temperatures for each thermocouple in pattern 1 and pattern 2, it was shown that the higher temperature was also measured in pattern 2 at the same point in Figure 10. The unit heat input is the same since both pattern 1 and pattern 2 deposited the same amount of heat input over the same area for the same time. The major difference between the two patterns is that the deposition with a long raster pattern has a larger surface area exposed to the atmosphere during the deposition. Analyzing this tendency, it can be seen that the heat loss from the DMT-AM process has a great effect on the radiation and convection caused by the contact between the deposited material and the atmosphere. Similarly, for patterns 1 to 6, the maximum temperature at each layer measured in the thermocouple 2 is compared in Figure 11. When deposited with a short raster pattern, the temperature rise gradient is larger than with the long raster pattern, but the temperature decrease gradient is also greater.