Wire Arc Additive Manufacturing (WAAM) produces metal components with crucial properties dependent on process parameters. Understanding the effects of these parameters on microstructure and mechanical properties is vital for optimizing WAAM. This study investigated the impact of varying travel speeds (TS) on the microstructure and mechanical properties of low carbon steel ER70S-6 alloy produced by WAAM process. The hypothesis centred on the impact of different TS values on heat input (HI) and cooling rates, and the subsequent effects on the resulting microstructure and mechanical properties of the deposited material. ER70S-6 alloy was deposited at three different TS: 120, 150, and 180 mm/min. Microstructure and mechanical properties (microhardness, tensile strength, elongation) were evaluated for each TS condition. Distinct microstructures were observed in the deposited samples, influenced by cooling rates at different TS. Distinct microstructures emerged in different regions of the deposits due to varying cooling rates at different TS. Higher TS (180 mm/min) significantly reduced pores and cracks while enhancing yield strength (YS) and ultimate tensile strength (UTS) up to 25.2 ± 0.77% elongation and 502.3 ± 3.17 MPa UTS, respectively. However, UTS remained slightly lower (93%) than the catalogued value for ER70S-6 (540 MPa), indicating a mild softening effect. TS significantly influenced the microstructure and mechanical properties of WAAM-produced ER70S-6 alloy. This study provides key insights into optimizing WAAM parameters for low carbon steel, paving the way for improved component production for diverse industrial applications.

Fused Filament Fabrication (FFF) is a widely adopted additive manufacturing technique, yet its mechanical performance is highly dependent on process parameters, particularly nozzle diameter and printing speed. This study evaluates the influence of these parameters on the tensile behavior of Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA), aiming to determine optimal conditions for enhanced strength. ASTM D638-Type IV specimens were printed using nozzle diameters ranging from 0.05 to 0.25 mm and speeds from 15 to 80 mm/s. For ABS, tensile strength increased from 56.46 MPa to 60.74 MPa, representing a 7.6% enhancement, as nozzle diameter increased, with the best performance observed at 0.25 mm and 45 mm/s, attributed to improved melt flow and interlayer fusion. PLA exhibited a non-linear response, reaching a maximum strength of 89.59 MPa under the same conditions, marking a 22.3% enhancement over the minimum value. The superior performance of PLA was linked to optimal thermal management that enhanced crystallinity and interlayer bonding. Fractographic analysis revealed reduced porosity and smoother fracture surfaces under optimized conditions. Overall, PLA consistently outperformed ABS across all settings, with an average tensile strength advantage of 47.5%. The results underscore the need for material-specific parameter tuning in FFF and offer practical insights for optimizing mechanical performance in applications demanding high structural integrity, including biomedical, aerospace, and functional prototyping.

Optimizing process parameters in Wire Arc Additive Manufacturing (WAAM) is essential for high-quality, cost-effective ER70S-6 steel components. This study investigated the impact of travel speed (TS) on porosity and microhardness. Inappropriate parameter selection led to defects like discontinuous beads and irregular layers. Importantly, lower TS (120 mm/min) resulted in significantly higher porosity (15.58%) due to increased heat input and trapped hydrogen. Conversely, higher TS (180 mm/min) yielded a substantial reduction in porosity (2.04%), highlighting its role in controlling pore formation. Microhardness exhibited a complex relationship with TS and location, with faster cooling in bottom and top regions leading to higher values (216 HV). Additionally, increasing TS increased microhardness throughout the deposit (197 HV) due to reduced heat input and faster cooling. Both image processing and density measurements confirmed the effectiveness of TS in controlling porosity, revealing a decrease in pore number and size with increasing TS. These findings emphasize that optimizing WAAM process parameters, particularly TS, is crucial for achieving minimal porosity and desired microhardness in ER70S-6 steel deposits, ultimately leading to high-quality, low-cost components

This study investigates the influence of key fiber laser cutting parameters, laser power, cutting speed, nozzle stand-off distance, and focus position, on the surface roughness of thick Al6061-T6 alloy, focusing on average surface roughness (Ra), areal surface roughness (Sa), and maximum peak-to-valley height (Sz). Using a Taguchi L27 orthogonal design and optical laser microscopy at various depths, surface quality was analyzed through main effects plots and ANOVA. Results identified nozzle stand-off distance as the most critical factor for minimizing Ra and Sa, with the smoothest surfaces achieved at a 1.0 mm, while focus position (–1.5 mm) provided secondary improvements in energy concentration. In contrast, Sz was mainly influenced by laser power and cutting speed, with greater values of both lowering peak roughness. The ideal parameter set, 2750 W, 600-750 mm/min, 1.0 mm nozzle standoff distance, and -1.5 mm focus, provided exceptional surface integrity, emphasizing the importance of balancing thermal input with accurate nozzle and focus settings for high-quality laser cutting of aluminum. The results indicate that although controlling thermal parameters such as laser power and cutting speed is essential for minimizing peak roughness features, achieving superior surface integrity in aluminum laser cutting also requires precise tuning of the nozzle stand-off distance and beam focus.