Operator Bias in the Estimation of Arc Efficiency in Gas Tungsten Arc Welding

Sikström, Fredrik

doi:10.1590/0104-9224/si2001.13

Cited by 6 publications

(5 citation statements)

References 8 publications

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“…These errors arise from the test principle (intrinsic errors), uncontrollable variables (random errors) and measurement accuracies (instrumental). Sikström 18 used a water-cooled stationary anode calorimeter as case study to determine errors in the measurement process of arc efficiency. He focused his study on instrumental errors, operator influence (manual operations that introduce operator bias in the measurement process, such as arc length setting) and welding leads voltage drop (measuring the potential between the terminals of the welding power source instead of measuring the potential between the electrode contact tube and the workpiece).…”

Section: Source Of Inaccuracies In Water-cooled Stationary Anode Calo...mentioning

confidence: 99%

A critical analysis of weld heat input measurement through a water-cooled stationary anode calorimeter

Hurtig

Choquet

Scotti

et al. 2016

Science and Technology of Welding and Joining

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Comprehensive models of heat transfer require specification of the total amount of heat received by the workpiece. The objective of this work was to critically examine the use of a water-cooled stationary anode calorimeter to obtain both arc efficiency and total heat input into the workpiece. For simplicity and clarity, this last quantity is called the gross heat input. The effects of current, material type and water flow rate on the calorimeter performance were determined experimentally. Some measures for reducing errors in calorimetry were evaluated. Improvements were made to reduce heat losses from the top surface of the test coupon and boost heat removal from the opposite surface. A sensitivity test was conducted to estimate the effect of measurement inaccuracies. The results demonstrate the effectiveness of calorimetry for measuring gross heat input in arc welding.

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Section: Source Of Inaccuracies In Water-cooled Stationary Anode Calo...mentioning

confidence: 99%

A critical analysis of weld heat input measurement through a water-cooled stationary anode calorimeter

Hurtig

Choquet

Scotti

et al. 2016

Science and Technology of Welding and Joining

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“…The effects of different operators over quality related aspects of the welding process is of great significance as reported by Ji et al [17]. Sïkstrom showed the variations in terms of process efficiency during Gas Tungsten Arc welding [18]. In the field of laser processing of metals, literature is sparse.…”

Section: Introductionmentioning

confidence: 99%

Hand-Held Laser Welding of AISI301LN for components with aesthetic requirements: Toward the integration of machine and human intelligence

Caprio

Borzoni

Previtali

et al. 2022

Journal of Laser Applications

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The use of Hand-Held Laser Welding (HHLW) systems in the industry has been rapidly growing in recent years as an alternative solution to conventional manual arc-based welding systems. The decreasing cost of fiber laser sources and optics has been a driving factor in enabling a wider use of HHLW systems, beyond the established advantages of laser technology with respect to arc-based systems. While the industrial use of HHLW increases, the subject matter has been studied sparingly in the scientific literature. Due to the intrinsic flexibility of the technology, HHLW systems are highly appealing for joining relatively low thickness metals (≤2 mm) in autogenous configuration in sectors where production lots present low batch and high variability. However, a critical aspect of HHLW is correlated to the operator skill, where welding velocities can vary within and between the welds affecting both their aesthetic and mechanical properties. Hence, the development of combined digital and physical approaches to support manual operations may be highly beneficial. The current study presents an open laboratory HHLW system designed for process development purposes. Beyond conventional manual welding operations, the welding torch could be arranged in different configurations. The system could be combined with a linear axis (enabling welding with stable velocity and inclination) or manually with the aid of a newly developed roller device designed to provide constant speed and inclination. First, the process was benchmarked by joining in butt weld configuration 2 mm thick AISI301LN stainless steel sheets with the linear axis. Successively, four operators with different levels of training (rookie and professional) realized welds with the system in hand-held configuration and with the mechanical roller. The weld width variability was assessed as a direct indicator for aesthetic compliance while tensile tests were allowed to determine the mechanical properties of the joint obtained with different configurations.

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“…Costa et al [12] utilizan la metodología de superficie de respuesta para el modelado de funciones objetivo (variables de respuesta con variables de entrada) y la optimización se realiza con algoritmos genéticos y la gráfica de frente de Pareto, siendo posible establecer modelos matemáticos empíricos satisfactorios para las variables de respuesta. Posteriormente, los autores en [13] realizan un estudio experimental con 15 operadores en el cual se estudia el sesgo de la eficiencia del arco, dando como resultado que el sesgo primordialmente es provocado por la caída del voltaje debido al mal estado de los cables de soldadura, siendo insignificante el factor de la manipulación del operador; estos resultados se evalúan estadísticamente.…”

Section: Introductionunclassified

Análisis Estadístico en Aplicación de Soldadura GTAW Usando Diseño de Experimentos Factorial Completo

et al. 2020

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Resumen: La determinación de los parámetros eléctricos y funcionales para aplicación de soldadura requiere realizar pruebas preliminares tanto en la industria como en la investigación. Sin embargo, este proceso resulta ser muy costoso, lento y, para objeto de investigación, de baja confiabilidad, por tal motivo, el desarrollo de una metodología de experimentación que permita obtener adecuadamente dichos parámetros es muy importante. El presente trabajo muestra el análisis estadístico para la aplicación de soldadura de arco metálico con electrodo de tungsteno y gas inerte (GTAW) utilizada para determinar la velocidad de avance de la antorcha y la corriente de soldadura óptimos para lograr soldadura libre de defectos. Con los resultados obtenidos en el diagrama causa-efecto (Ishikawa) se permite la interpretación efectiva de la causa raíz de los defectos, reduciendo el número de experimentos, posteriormente el diagrama de árbol da pauta para definir la matriz experimental. La validación de la experimentación se hace con el diseño de experimento factorial completo, la efectividad proporcionada por el cálculo del coeficiente de determinación, también conocido como nivel de correlación, de 94,24% en penetración del cordón y 85,03% en ancho del cordón. La gráfica de residuales y valores predichos valida la distribución del error en las probetas.

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Operator Bias in the Estimation of Arc Efficiency in Gas Tungsten Arc Welding

Cited by 6 publications

References 8 publications

A critical analysis of weld heat input measurement through a water-cooled stationary anode calorimeter

A critical analysis of weld heat input measurement through a water-cooled stationary anode calorimeter

Hand-Held Laser Welding of AISI301LN for components with aesthetic requirements: Toward the integration of machine and human intelligence

Análisis Estadístico en Aplicación de Soldadura GTAW Usando Diseño de Experimentos Factorial Completo

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