Enhancement of Additive Manufacturing Processes for Thin-Walled Part Production Using Gas Metal Arc Welding (GMAW) with Wavelet Transform  
[PERSON]  
1 Department of Mechanical Engineering, Birjand University of Technology, Birjand 9719866981, Iran;  
[EMAIL_ADDRESS]  
[PERSON]  
2 Department of Technology and Aesthetics, Blekinge Institute of Technology, 37179 Karlskrona, Sweden;  
siamak.khati  
The distinctive capabilities of additive manufacturing, particularly mass customization and the production of lightweight components, offer substantial potential for enhancing efficiency, expanding applications, and creating environmentally friendly products when integrated with the Internet of Things and data in the Fourth Industrial Revolution [3]. Modern additive manufacturing technologies have found extensive applications in various fields, including aerospace, maritime, medical, automotive, and energy sectors, owing to their capacity to generate integrated and complex geometries, high production speed, desirable strength, high density, optimal material utilization, design freedom, and potential for cost reduction [4; 5; 6; 7; 8]. Notable techniques among these methods include Selective Laser Sintering (SLS), Direct Metal Deposition (DMD), Laser-Based Additive Manufacturing (LBAM), Directed Light Fabrication (DLF), Electron Beam Additive Manufacturing (EBM), and Wire Arc Additive Manufacturing (WAAM) [9; 10; 11; 12]. In recent years, one particularly notable technology in additive manufacturing for metals has been identified as Wire Arc Additive Manufacturing (WAAM). This method excels at fabricating complex geometric metal components and has been the subject of numerous studies due to its high level of automation [13]. Compared to other additive manufacturing methods, such as Powder Bed Fusion (PBF) using lasers, WAAM exhibits a higher deposition rate for producing large-scale components. While WAAM systems are increasingly employed in industrial and academic domains, several challenges and obstacles still need to be overcome to maintain process stability [14]. In additive manufacturing using the WAAM method to produce components, layer deposition is carried out based on information derived from a 3D model. During the layer deposition process in the additive manufacturing method based on Gas Metal Arc Welding (GMAW), a metal wire is melted using an electric arc and deposited onto the previously formed weld bead, thus forming a new layer. The crucial aspect of this process lies in the non-uniformity of the deposited weld bead [15; 16]. Figure 1 provides a schematic representation of the GMAW process. This welding process is highly versatile and can be employed in automatic or semi-automatic modes by connecting it to a CNC machine or a robotic arm. The adjustable parameters in the GMAW process, which significantly influence penetration depth, weld bead geometry, and overall weld quality, include current intensity, voltage, welding speed, wire type, diameter, and wire feed rate [17; 18; 19]. In particular, when constructing layer-by-layer components, the accuracy of the weld bead is paramount to accurately represent geometry and prevent process irregularities [20]. Due to the high sensitivity of the GMAW process to minor changes in deposition parameters, such as arc current, deposition rate, arc voltage, layer geometry under different heat dissipation conditions, interlayer temperature, quality of previous layer surfaces, and substrate deformation, a critical issue in additive manufacturing based on GMAW is the variation in the height of the deposited layer. This variation results in low and high spots  
Figure 1: GMAW process schematic [17]. that can accumulate during the additive process, leading to the formation of porosity or an inadequate layer shape.