Experimental Investigation of Deposition Pattern on the Temperature and Distortion of Direct Energy Deposition-Based Additive Manufactured Part  
[PERSON]  
1 Department of Naval Architecture and Ocean Engineering, Chonnam National University,  
Yeosu 59626, Korea; [EMAIL_ADDRESS]  
2 Department of Naval Architecture & Ocean Engineering, Chungnam National University,  
Daejeon 34134, Korea  
2  
[PERSON]  
distortion and residual stress but also the mechanical characteristics of the AM parts [11]. The most flexible process parameter among these variables is the deposition pattern. Travel speed, powder mass flow rate, beam diameter and laser power directly affect the unit heat input and the deposit shape [12]. Considering that the principle of AM is slicing the Computer-Aided Design (CAD) part into designated height and width to schedule the tool path, those parameters should be predetermined in order to plan the tool path. However, it is possible to consider various deposition patterns such as short raster pattern, long raster pattern, spiral pattern, etc. for each layer since the deposition pattern does not affect the deposit shape. Therefore, it is necessary to analyze the temperature distribution and the distortion of the AM part according to the deposition pattern which is the most flexible method to reduce the distortion.  
Several researchers have studied the influence of deposition pattern on the residual stress distribution and mechanical patterns of AM parts. From the literature survey, it can be seen that the anisotropy of the mechanical property is generated by the single direction deposition pattern [13; 14; 15]. For the Fused Deposition Modeling (FDM) based AM, several researchers have studied the influence of deposition pattern on the mechanical properties of the manufactured parts [16; 17; 18]. Therefore, it is understood that the deposition pattern should be designed uniformly in various directions rather than a single direction to prevent such anisotropy. However, experimental works that show these various deposition patterns affecting the distortion pattern and temperature distribution have not been well studied. [PERSON] and [PERSON] [19] conducted an experimental and numerical study on the distortion and residual stress distribution of surface cladding according to the different deposition strategies. However, this study provided only a single layer deposited AM structure. [PERSON] et al. [20] showed that the deposition pattern in the AM process has a significant effect on the part residual stresses and deflections. However, this study only showed the longitudinal deflection value according the deposition pattern. According to various welding distortion studies [21; 22; 23], there are several types of welding distortion and these distortions occur simultaneously. So to clearly understand how the deposition pattern affects the distortion, not only the longitudinal deflection value but also the global distortion tendency should be investigated.  
Therefore, this study focuses on the influence of deposition pattern on the global distortion and the temperature distribution of the AM parts. In this study, DMT-based AM process with SUS304 powder was used on the SM45C substrate to build four layered deposited specimens. Six different patterns were designed that are combined with long raster and short raster patterns. In situ temperature measurements were used to monitor the temperature of the substrates and global distortion patterns were analyzed using CMM (Coordinate Measuring Machine) after the deposition. The resulting trends were analyzed, and the results will be helpful to understand and control the distortion and the maximum temperature of AM parts by optimizing the deposition pattern.