MODELLING AND OPTIMIZING OF A MIG WELDING PROCESS—A CASE STUDY USING EXPERIMENTAL DESIGNS AND NEURAL NETWORKS

This paper describes an application of an integrated method using experimental designs and neural network technologies for modelling and optimizing a metal inert gas (MIG) welding process. To achieve optimization, the process parameters must be adjusted in such a way that the deviations from target are minimized while the robustness to noise and to process fluctuations are maximized. This new method consists of an experiment reference template for designing and collecting training data samples, and a parallel distributed computational adaptive neural network system to provide a powerful tool for data modelling and empirical investigations. The relevant data is established using experimental design methods and highlighted in the case study. An adaptive GaRBF neural network is used to approximate the stochastically non-linear dynamics of the welding process to optimize the basic welding parameters. The neural network is trained with welding experimental data, tested and compared in an actual welding environment in terms of its ability to determine weld quality. The results show that the proposed adaptive neural network is capable of mapping the complex relationships between the welding parameters and the corresponding output weld quality. The implementation for this case study was carried out using a ‘semi-automatic’ welding facility, to mass weld a 20″ × 0.438″ pin/box onto a 20″ × 0.5″ × 37′ pipe (tubular drilling products), in an actual workshop which makes oilfield equipment. The entire range of welding combinations that might be experienced during actual welding operations is included to study the weld quality. © 1997 by John Wiley & Sons, Ltd.     

多弧物理气相沉积技术制备（TiAl）N超硬膜

主要介绍采用多弧物理气相沉积（ＰＶＤ）技术研制新型（ＴｉＡｌ）Ｎ超硬膜的工艺技术特点。对其膜层相结构、化学成分、显微组织等方面做了分析研究。结合工业生产实际应用进行了（ＴｉＡｌ）Ｎ与ＴｉＮ涂层刀具切削耐用度对比试验。     

真空冷却过程中水分蒸发沸腾的数值模拟（Ⅰ）：模型的建立

真空冷却过程是复杂的相变传热传质过程。在真空冷却期间,当真空室内的真空压力低于或者等于熟肉温度对应的饱和压力时,熟肉内部的水分将会沸腾蒸发以产生冷却效应。在能量和质量守恒的基础上,经过适当的简化,建立了真空冷却过程中水分迁移的数学模型。此模型能够预测真空冷却过程中熟肉内部的温度、压力和水分含量分布。     

YBa_2Cu_3O(7-x)超导粉的合成及其质量鉴别

用红外光谱测定 YBa_2Cu_3O_(7-x) 合成过程中碳酸根含量的变化,用燃烧-气相色谱法测定碳含量,以此作为判据,评定合成粉品质,并由此确定 YBa_2Cu_3O_(7-x) 的合成工艺。