The quick developments of artificial intelligence have brought tremendous attractive opportunities and changes to smart welding technology. In the present work, a novel model, ConvNeXt, which incorporates the advantages of convolutional neural networks (CNNs) and vision transformers (ViTs), has been designed to identify welding defects. The classification accuracy of the pre-trained ConvNeXt based on transfer learning method reaches as high as 99.52% after 500 iterations of training, while traditional CNNs of MobileNetV2 and ResNet34 achieve 85.94% and 93.41%, respectively. Moreover, the classification performance can be further improved through dataset optimization based on t-distributed stochastic neighbor embedding (t-SNE). In addition, arc geometrical features are added as input parameters for building a back propagation neural network to predict the formation of the weld seam, which has led to a reduction in the maximum prediction error for weld seam thickness from 0.8 to 0.6 mm. Furthermore, out of 28 sets of experimental parameters, only four sets result in errors exceeding 0.2 mm. It is worth noting that large language models (LLMs) are utilized to facilitate the automated programming for welding defect recognition, including ChatGPT 3.5, Bing Copilot, Claude3, and ERNIE Bot. LLM-aided automated programming technology is applied to develop image stitching programs, achieving unsupervised automatic stitching of multiple welding tissue images and obtaining clear and wide-field weld ones. These case studies of deep learning technologies and automated programming based on LLMs set up a solidified building block for smart welding defect recognition during non-equilibrium solidification.
