Saeheaw Teerapun
Department of Teacher Training in Mechanical Engineering, King Mongkut's University of Technology North Bangkok, Bangkok, Thailand.
Heliyon. 2022 Nov 1;8(11):e11349. doi: 10.1016/j.heliyon.2022.e11349. eCollection 2022 Nov.
There is a need to study the multi-objective optimization technique as the appropriate method to enhance welding qualities under optimal process conditions. Therefore, this study investigated the application of the integrated Criteria Importance Through Intercriteria Correlation (CRITIC), which is an objective weighting technique, and the Grey Relational Analysis (GRA)-based Taguchi method to solve multiple criteria optimization problem in the Nd:YAG laser welding process. The Taguchi-based L36 orthogonal array table was employed in this study to optimize six process parameters, including the beam diameter, laser power, flow rate, welding speed, laser offset, and pulse shape, with the aim to simultaneously achieve maximum weld strength and minimum weld width. The base metal JIS G3141 SPCC steel with 0.5 and 1.0 mm thicknesses was used in the present experiment. Following the welding process and optimization, the weld strength was measured using a Cometech QC-506M1 universal testing machine, while the weld width was determined under a Nikon SMZ25 stereomicroscope. Based on the results, the weight fractions of the weld strength and weld width from the applied CRITIC method were equal to 0.4157 and 0.5843, respectively. Meanwhile, the GRA revealed that the process parameters recorded an optimal setting for beam diameter of 0.8 mm, flow rate of 8 L/min, laser power of 0.6 kW, welding speed of 2.5 mm/s, laser offset of 0.2 mm, and pulse shape I. Furthermore, the weld strength and the weld width were enhanced from 236 to 328 MPa and from 1.13 to 1.04 mm, respectively. Additionally, the Analysis of Variance (ANOVA) indicated that the laser power and welding speed were the most influential parameters on the welding qualities. Most importantly, the findings of the confirmation experiment showed that the proposed approach was able to effectively identify the optimal laser welding parameters, which ultimately improved the multiple quality characteristics.
有必要研究多目标优化技术，将其作为在最佳工艺条件下提高焊接质量的合适方法。因此，本研究调查了基于客观加权技术的综合准则重要性通过准则间相关性（CRITIC）以及基于灰色关联分析（GRA）的田口方法在Nd:YAG激光焊接过程中解决多准则优化问题的应用。本研究采用基于田口方法的L36正交阵列表来优化六个工艺参数，包括光束直径、激光功率、流量、焊接速度、激光偏移和脉冲形状，目的是同时实现最大焊接强度和最小焊缝宽度。本实验使用了厚度为0.5毫米和1.0毫米的JIS G3141 SPCC钢母材。焊接过程和优化之后，使用Cometech QC - 506M1万能试验机测量焊接强度，同时在尼康SMZ25立体显微镜下测定焊缝宽度。基于结果，应用CRITIC方法得到的焊接强度和焊缝宽度的权重分数分别为0.4157和0.5843。同时，灰色关联分析表明，工艺参数的最佳设置为光束直径0.8毫米、流量8升/分钟、激光功率0.6千瓦、焊接速度2.5毫米/秒、激光偏移0.2毫米和脉冲形状I型。此外，焊接强度和焊缝宽度分别从236兆帕提高到328兆帕，从1.13毫米减小到1.04毫米。另外，方差分析表明激光功率和焊接速度是对焊接质量影响最大的参数。最重要的是，验证实验的结果表明，所提出的方法能够有效地识别最佳激光焊接参数，最终改善了多个质量特性。
