Optimization of molding sand composition for quality improvement of iron castings

Saikaew, Charnnarong; Wiengwiset, Sermsak

doi:10.1016/j.clay.2012.07.005

Cited by 76 publications

(47 citation statements)

References 14 publications

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“…It has advantages of lower cost of tooling, wider range of metals, and less constraints in part geometry, especially when compared to permanent mold processes [1]. Several steps are however, involved in producing sand molds, including sand preparation, sand filling in mold, stripping the pattern, and placing the cores.…”

Section: Introductionmentioning

confidence: 99%

Effect of Binder Composition on the Shrinkage of Chemically Bonded Sand Cores

Khandelwal

Ravi

2014

Materials and Manufacturing Processes

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Modern foundries increasingly use chemically-bonded no-bake sand cores and molds because they provide ease of molding, good surface finish, and collapsibility. One of the most popular binder systems is alkyd oil urethane no-bake system comprising three parts: alkyd resin, catalyst, and crosslinking agent. Their amounts and ratios can influence mold shrinkage, and thereby dimensional quality of the resulting casting. With rising emphasis on net-shape casting, there is a need to optimize the binder composition to minimize dimensional errors, while achieving the desired bench life, stripping time and hardness.This work investigates the effect of binder composition on the dimensions of chemicallybonded sand cores with respect to time. The maximum shrinkage of 0.15% over length was observed when resin content was 2.4% by weight of sand. The rate of shrinkage increased with the amount of catalyst. Measurement of core hardness and reduction in weight, followed by SEM studies provided a better understanding of the underlying phenomena, especially formation of resin bridges between compacted sand particles and evaporation of solvent. This work is expected to aid in selection of the most appropriate binder composition for a given set of molding process constraints and cast product requirements.

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Section: Introductionmentioning

confidence: 99%

Effect of Binder Composition on the Shrinkage of Chemically Bonded Sand Cores

Khandelwal

Ravi

2014

Materials and Manufacturing Processes

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“…Modern foundry uses chemical bonded no bake sand mould system as it has enhanced shelf life, strength, dimension accuracy and surface finish [1]. Sand moulds were preferred to permanent mould due to several technical advantages, namely, low process cost, ease of mould making, minimized constraints on part geometry and castability of different metals [2]. Sand drop defects in casting are always the result of mould hardness, which in turn is influenced by grain fineness, quantity of binder (resin and hardener), curing time, degree of ramming and so on.…”

Section: Introductionmentioning

confidence: 99%

“…Taguchi method optimizes the moulding sand variables to locate the highest possible tensile strength [19] and minimizes casting defects [15]. The green sand mould process variables are optimized for compression strength, permeability and mould hardness using the desirability function approach (DFA) and RSM [20]. Statistical (DOE, RSM, DFA, and Taguchi method) optimization tools follow deterministic search method with particular rules to locate the optimal solution for different manufacturing processes [15,[18][19].…”

Section: Introductionmentioning

confidence: 99%

“…Statistical (DOE, RSM, DFA, and Taguchi method) optimization tools follow deterministic search method with particular rules to locate the optimal solution for different manufacturing processes [15,[18][19]. The success of the DFA in the recent literature [20][21] has motivated us to locate an optimal solution for extreme values of mould hardness and permeability.…”

Section: Introductionmentioning

confidence: 99%

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Modeling and Optimization of Phenol Formaldehyde Resin Sand Mould System

Chate¹,

Patel

Parappagoudar³

et al. 2017

Archives of Foundry Engineering

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Chemical bonded resin sand mould system has high dimensional accuracy, surface finish and sand mould properties compared to green sand mould system. The mould cavity prepared under chemical bonded sand mould system must produce sufficient permeability and hardness to withstand sand drop while pouring molten metal through ladle. The demand for improved values of permeability and mould hardness depends on systematic study and analysis of influencing variables namely grain fineness number, setting time, percent of resin and hardener. Try-error experiment methods and analysis were considered impractical in actual foundry practice due to the associated cost. Experimental matrices of central composite design allow conducting minimum experiments that provide complete insight of the process. Statistical significance of influencing variables and their interaction were determined to control the process. Analysis of variance (ANOVA) test was conducted to validate the model statistically. Mathematical equation was derived separately for mould hardness and permeability, which are expressed as a non-linear function of input variables based on the collected experimental input-output data. The developed model prediction accuracy for practical usefulness was tested with 10 random experimental conditions. The decision variables for higher mould hardness and permeability were determined using desirability function approach. The prediction results were found to be consistent with experimental values.

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“…Central composite design of experiments can be applied to investigate the effects of predominance factors like bentonite, water, curing time and sand mixture on sand mold properties [5]. Mixture experimental design and response surface methodology can be used to optimize the composition of the molding sand mixture for reducing the number of casting defects [6]. A strategy to find optimum values of process factors in casting process and a considerable improvement in reduction of casting defects was achieved in this research.…”

Section: Introductionmentioning

confidence: 99%

Quality Improvement of a Casting Process Using Design of Experiments

et al. 2016

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In order to minimize the castings which do not meet the customer acceptance specifications, it is not only necessary to identify the process parameters related to the specific defects, but also it is necessary to identify the levels of these parameters to produce acceptable castings. This research study, was aimed to optimize the production of grey cast pump impellent castings using Response Surface Methodology (RSM) approach in a foundry producing grey cast iron components. Process factors like clay percentage, moisture percentage and mold hardness were found to be dominant factors for production process control. Three different levels of each factor were considered for experimentation. Statgraphics Centurion Statistical Software was used to analyze and optimize process parameters for further confirmatory experiments. Significant parameters were identified by means of an Analysis of Variance (ANOVA) test. Parameter optimal settings obtained, and validated from confirmatory experiments, produced a high per cent of defect free pump impeller castings. The research concluded that careful adjustment of process dominance parameters is necessary, since they have significant effects on quality improvement of castings produced. RESUMENPara minimizar la cantidad de piezas fundidas que no cumplen las especificaciones de los clientes, es necesario no sólo identificar los parámetros relacionados con los defectos específicos, sino también identificar los niveles de estos parámetros para elaborar piezas aceptables. Este estudio de investigación, fue orientado a optimizar la producción de impelentes de bombas, utilizando la Metodología de Superficies de Respuesta (RSM) en una empresa productora de componentes de fundición gris. Factores tales como los porcentajes arcilla y de humedad, así como la dureza del molde resultaron predominantes para el control del proceso de producción. Tres niveles diferentes de cada factor fueron considerados para la experimentación. El paquete de Software Estadístico Statgraphics Centurion fue utilizado para analizar y optimizar los parámetros del proceso, cuyos valores fueron ajustados mediante experimentos de confirmación . Los parámetros más importantes fueron identificados por medio del Análisis de Varianza (ANOVA). La configuración óptima de los paráme-tros del proceso, validada por las corridas experimentales confirmatorias, produjo un elevado porcentaje de impelentes no defectuosos. Esto permitió concluir que es necesario el ajuste cuidadoso de los parámetros de predominio del proceso, porque estos tienen efectos significativos en el mejoramiento de la calidad de las piezas producidas. Palabras clave: Diseño de Experimentos; Calidad de las Piezas Fundidas; Metodología de Superficies de Respuesta; Análisis de la Varianza (ANOVA); Optimización; Mejora de la Calidad en la Fundición.

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Optimization of molding sand composition for quality improvement of iron castings

Cited by 76 publications

References 14 publications

Effect of Binder Composition on the Shrinkage of Chemically Bonded Sand Cores

Effect of Binder Composition on the Shrinkage of Chemically Bonded Sand Cores

Modeling and Optimization of Phenol Formaldehyde Resin Sand Mould System

Quality Improvement of a Casting Process Using Design of Experiments

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