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It has been well recognized that the geometry of weld pool plays a fundamental role in determining the mechanical properties of weld joints. In this research, a series of experiment has been conducted to investigate the interaction and correlation of welding current, voltage, welding speed, and arc length affecting the formation of weld pool. The effect of arc length on arc efficiency and heat distribution parameter are also examined and addressed in this paper. In addition to the experimental study, a three-dimensional finite element model has been developed to analyze transient heat flow and to predict the formation of the weld pool. The correlation among the parameters including welding current, voltage, welding speed, arc length, open-loop response and the characteristic geometry of weld pool are established. The 3-D FEM can calculate not only the transient thermal histories but also the sizes of weld pool in single-pass arc welding. In order to obtain quality welds, this model will determine the effect of arc length on the formation of weld. Furthermore, the effects of welding parameters on the Gaussian heat source parameters (arc efficiency and heat distribution parameter) are also studied. The experimental calibration and verification are carried out to verify the numerical model. Experimental data are consistent and in quantitative agreement with values from FEM simulations.

Byline: Chi-Chia Liu, Min Jou, Han-Chiang Lee Recently, e-learning technology has been applied to every kind of specialised education field. However, these systems are developed based on a browser and HTML environment. The major capabilities of these systems are limited to presenting course contents to students. Because of the framework limitations for developing e-learning systems, students' practical abilities cannot be performed or disciplined through a developed e-learning system. Currently, practical training is still applied on the shop floor to discipline students' practice abilities. How to build up students' practice ability through an e-learning system is an important research issue. This study employs virtual reality techniques to develop an interactive virtual laboratory to discipline students' practice ability using the internet. Four kinds of manufacturing technology are established in this system: turning, milling, spraying and laser marking. This system allows students to select different process parameters to learn entire manufacturing processes in real time. Further, this study applies information theory to develop a semantic interface for students to present their queries in nature language. This study has opened up an opportunity of change to the traditional practical training method. The developed system provides students with a syntactic and semantic way to learn manufacturing technology.

Byline: Kueng-Hueng Tseng, Min Jou, Yun Chang, Her-Yueh Huang The objectives of this research are to investigate the effect of welding parameters on the weld quality and to develop guidelines for a selection of suitable parameter ranges for microplasma welding. A series of experiments was conducted to explore how changes of welding parameters affect the strength of the weld for the thin stainless steel most often used in the industry. The experiment results show that workpiece exposure height must be above a minimum limit in order to prevent undesired joining. The strength increases as the current increases, with fluctuations, but still in the sufficient range. The minimum sufficient current for quality welds increases, while the minimum sufficient heat input decreases, as the travel speed increases.