Yangtze River Delta G60 laser alliance guide
墨西哥国家增材和数字制造实验室（MADiT）、墨西哥国立自治大学及墨西哥蒙特雷理工大学的科研人员报道了工艺参数对金属LPBF工艺制造零件的粗糙度和拉伸性能的影响的研究。 相关研究成果以“Effect of process parameters on the roughness and tensile behavior of parts manufactured by the metals LPBF process”为题发表在《Engineering Reports》上。
The Metal Laser Powder Bed Fusion Process (LPBF-M) produces random surface features that can greatly affect the interaction of the part with its surroundings as well as the mechanical properties of the part. Process parameters affect surface quality, which is quantified by surface roughness. As a result, customizing surface roughness during the manufacturing process can greatly contribute to the achievement of ready-to-use parts, reducing the need for extensive surface post-treatment. In this paper, the theoretical estimation of melt pool depth under the conditions of isolinear energy density, equal power and constant temperature manufacturing process parameters is used. These estimates are then compared with experimental evaluations of the surface roughness and tensile strength of the upright specimen to extract trends between input energy and roughness and between input energy and tensile behavior. The results show that the isoenergetic values produce similar roughness due to the expected consistent melt pool depth. In addition, an increase in the depth of the melt pool results in a higher surface roughness, while a smaller melt pool size results in improved roughness. In addition, a comparison between melt pool size and tensile test performance shows that tensile strength is adversely affected for specimens with a small estimated melt pool depth.
Figure 1: Plain interview specimen prepared according to ASTM E8 standard; Geometric properties, contour strategies, and vertical surface roughness characterization strategies.
Figure 2: Diagram of the shape of the melt pool. The intersection of the theoretical dimensions and superimposed trajectories of the LEDs through the layer thickness.
Figure 3: Laser power and scanning speed are selected according to the conditions of equal LED, equal temperature, and same power.
Figure 4: Surface roughness and melt pool depth results for each batch.
Figure 5: Contour measurement results based on LED conditions.
Figure 6: Stretch results for each batch.
Figure 7: Fracture and cross-section reduction for all batches.
This study examines different LED conditions achieved by varying laser power and scanning speed to evaluate their effects on surface roughness and tensile behavior. The results showed that the arithmetic mean roughness (Ra) of batches manufactured with the same LEDs was similar and showed an upward trend with the increase of LEDs. Changes in LED conditions can change the surface and tensile behavior through the scanning speed. In terms of tensile properties, the shape of the melt pool determines the properties.
The experimental setup showed that a linear energy density (LED) of 0.25 J/mm was generated according to the manufacturer's recommended combination of scan speed and laser power, providing the most stable conditions for replicating the results. However, with the same LEDs, lower surface roughness and higher strain, tensile strength, and elongation can be obtained using lower laser powers (200W and 300W). Conversely, increasing the laser power to 400W results in an increase in the estimated temperature and a decrease in strain and result consistency. To assess the generalizability of these findings, further research on other alloys is necessary.
Paper Links:
https://doi.org/10.1002/eng2.12904
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