Research on droplet transfer in oscillating arc narrow gap GMA welding

In this paper, the droplet transfer in oscillating arc narrow gap gas metal arc （ GMA ） welding was studied. According to the experimental results, the oscillating arc has effect on the droplet transfer mode. The droplet transfer frequency in narrow gap groove is higher than that in bead-on-plate welding. Because of the change of arc location in narrow gap groove, the droplet transfer in oscillating arc narrow gap changes regularly. The droplet transfer frequency near groove sidewall is higher than that at the middle of narrow gap groove.

A Study on the Optimal Offset Distance Between a Welding Torch and the Infrared Thermometers

Detection of weld defects using real-time monitoring and controlling algorithm is of the significant task in manufacturing industries due to the increased production and liability costs that result when weld defects are not identified early in the production cycle.Monitoring and controlling for robotic arc welding process employed should be reliable,flexible and cost-effective in non-clean,high-volume production environments.Also,the robotic welding system has been utilized a complex jigging and mechanical devices to move the workpiece which related to the stationary welding head for getting higher efficiency and lower costs.To develop the fully robotic welding system,people make use of their senses of sound and/or sight to collect welding information,and take the necessary corrective measurements to ensure the weld quality after processing is satisfactory.Therefore,it is really required that the monitoring and controlling algorithm of sensors for increasing effectiveness in the robotic welding process has been developed.In this paper,bead-on-plate welding using an infrared thermography in the robotic GMA(Gas Metal Arc)welding process has been performed to study the effects of welding parameters on thermal profile characteristics and find the optimal offset distance which applied for monitoring and controlling of welding quality such as bead height.The analysis for correlation between temperature distributions at three offset distance and bead height which based on the regression analysis such as Standard Error of Estimate(SEE),the coefficient of correlation(R)and coefficient of determination(R2)and(Predictive Ability of Model)has been done.The infra-red sensor is useful for monitoring the isotherm radii that arise during the robotic welding process and identifying bead height as welding quality.

Development of mathematical model with a genetic algorithm for automatic arc welding process

This paper is to represent new algorithms to predict process parameters on top-bead width in robotic gas metal arc（GMA） welding process.The models have been developed：linear, curvilinear and intelligent model based on full factorial design with two replications.Regression analysis was employed for optimization of the coefficients of linear and curvilinear models, while genetic algorithm（GA） was utilized to estimate the coefficients of an intelligent model.Not only the fitting of these models were checked and compared by using a variance test（ANOVA）, but also the prediction on top-bead width using the developed models were carried out based on the additional experiments.The developed models were employed to investigate the characteristic between process parameters and top-bead width.Resulting solutions and graphical representation showed that the intelligent model developed can be employed for prediction of bead geometry in GMA welding process.