• Journal of Welding and Joining
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• 제15권3호
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• pp.118-127
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• 1997

With the trend towards welding automation and robotization, mathematical models for studying the influence of various variables on the weld bead geometry in gas metal arc (GMA) welding process are required. Partial penetration, single-pass bead-on-plate welds using the GMA welding process were fabricated in 12mm mild steel plates employed four different process variables. Experimental results has been designed to investigate the analytical and empirical formulae, and develop mathematical equations for understanding the relationship between process variables and weld bead geometry. The relationships can be usefully employed not only for open loop process control, but also for adaptive control provided that dynamic sensing of process output is performed.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.30-35
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• 2008

As the quality of a weld feint is strongly influenced by process parameters during the welding process, an intelligent algorithms that can predict the bead geometry and shape to accomplish the desired mechanical properties of the weldment should be developed. This paper focuses on the development of mathematical models fur the selection of process parameters and the prediction of bead geometry(bead width, bead height and penetration) in robotic GMA(Gas Metal Arc) welding. Factorial design can be employed as a guide for optimization of process parameters. Three factors were incorporated into the factorial model: arc current, welding voltage and welding speed. A sensitivity analysis has been conducted and compared the relative impact of three process parameters on bead geometry in order to verify the measurement errors on the values of the uncertainty in estimated parameters. The results obtained show that developed mathematical models can be applied to estimate the effectiveness of process parameters for a given bead geometry, and a change of process parameters affects the bead width and bead height more strongly than penetration relatively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1845-1848
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• 2005

The automatic $CO_2$ welding is a manufacturing process to produce high quality joints for metal and it could provide a capability of full automation to enhance productivity. Despite the widespread use in the various manufacturing industries, the full automation of the robotic $CO_2$ welding has not yet been achieved partly because the mathematical model for the process parameters of a given welding task is not fully understood and quantified. Several mathematical models to control welding quality, productivity, microstructure and weld properties in arc welding processes have been studied. However, it is not an easy task to apply them to the various practical situations because the relationship between the process parameters and the bead geometry is non-linear and also they are usually dependent on the specific experimental results. Practically, it is difficult, but important to know how to establish a mathematical model that can predict the result of the actual welding process and how to select the optimum welding condition under a certain constraint. In this research, an attempt has been made to develop an intelligent algorithm to predict the weld geometry (top-bead width, top-bead height, back-bead width and back-bead height) as a function of key process parameters in the robotic $CO_2$welding. A sensitivity analysis has been conducted and compared the relative impact of three process parameters on bead geometry in order to verify the measurement errors on the values of the uncertainty in estimated parameters.

• 한국응용곤충학회지
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• 제34권2호
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• pp.89-94
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• 1995

${LC}_{50}$에 의한 살충제 저항성 사험결과 지역에 따라 pirimicarb가 49~830배 phosphamidon이 31~536배, demeton S-methyl이 5~204배의 약제 저항성이 확인됨으로서 사과에 조팝나무진딧물이 포장에서 방제결과가 없는 난방제해충이 되었음을 알 수 있다. 이와 같이 약제에 따라, 지역에 따라 저항성차가 크게 나타나는 원인을 공시충을 채집한 과수원의 살충제 산포상황을 조사한 결과 저항성이 가장 높았던 예산과 이천-1의 개체군을 채집한 과수원에서는 살충제를 4회 이상산포하였고, 저항성이 가장 낮았던 개체별 esterase 활성을 활성지수별로 분포비율을 비교한 결과 활성지수가 원주는 낮은 곳에, 이천-1과 예산은 높은 곳에 집중적으로 분포하였으며, 효소의 활성지수로써 저항성도를 계산한 결과 원주는 44.5, 이천-1과 예산은 92.0이었고 기타의 개체군들은 약제산포회수가 적어 이 사이에 모두 분포하였음을 알 수 있어 포장에서 약제산포회수가 많을수록 효소의 활성이 높게 나타났고 저항성비도 높았다. 이들중 광주(조팝나무)를 S크론, 과천(사과)을 R크론으로 하여 AChE의 조해제에 대한 감수성을 조사한 결과 pirimicarb는 299.2배, phosphamidon은 186배나 저하되었다. 이로써 약제저항성이 높았던 크론에서 에스테라제의 활성이 높았고, AChE의 감수성이 저하되는 것으로 보아 조팝나무진딧물의 약제저항성기작에는 적오도 두가지 이상의 요인이 작용하고 있음이 확인되었다.