Mould Hardness Research Articles

Experimental Study on Effect of Sand Grain Size and Heat Dissipation on the Properties of Moulding Sand

The rate of heat dissipation affects the solidification of the casting. A controlled cooling rate is necessary to produce defect-free castings. Sand qualities such as green compression strength, permeability, flow ability, mould hardness, and compactibility play a key role in controlled cooling or uniform heat flow across the casting. A research is executed in this paper to see how these properties affect the heat dissipation rate. The coarse grain and fine grain sand particle sizes are the most important influencing elements. The solidification time for casting in coarse, medium, and fine grains was noted in the results, and it was discovered that the cooling rate is better for coarse sand grains, as well as a relationship between solidification time and sand qualities was developed. During the experimental results it was observed that highest value of compactability was found to be 72% in case of medium sand, highest value of flowability was found out to be 87% in case of medium sand and highest value of permeability number was found in case of course sand particles i.e. 471.

Investigations into the Mould Variability of Process Parameters in Green Sand Moulds for Mould Characterization in the Casting Process

In this study, the time-temperature behaviour of selected process parameters is established. The paper describes a new approach to understanding the defect generation phenomena in castings by considering the uniqueness of individual green sand moulds. It also explains the changing values of process parameters by experimental investigation. Foundry is the science of experiments. The aim is to achieve the right quality, quantity, and cost with minimum rejections. The casting quality results from several interconnected, dynamic, and complicated processes that are part of a foundry operation. Quality castings are produced by exercising proper control over several process parameters involved in the casting process. Despite taking several control measures regarding proper casting design, methoding and processing, casting defects are still observed. Defect reduction continues to be the primary goal in sand casting foundries due to the same. This paper investigates the essential parameters of the Green Sand casting process for understanding the influence over the generation of the casting defect in green sand moulding grey cast iron components. This study also adopts the time series method of recording the process parameters and finding the values of process parameter sets for individual moulds. The results showed a systematic predictive behaviour of the selected process parameters. By recording the process parameters under given conditions, it is found that they are time and temperature-dependent. Values can be obtained by building regression equations. It has been found that values of per cent moisture and green compressive strength reduce, whereas permeability and mould hardness increase.

Experimental Investigation of the Influence of Sand and Binder Composition on the Mold Properties of Alkyd Type No-Bake Chemically Bonded Sand-Casting System

In comparison to green sand moulds, chemically bonded resin sand moulds have better dimensional accuracy, surface quality, and sand mould qualities. To survive sand drops when pouring molten metal, the mould cavity formed using a chemically bonded sand mould technique must have appropriate permeability, strength, and hardness. The desire for better permeability, strength, and mould hardness is based on a thorough investigation and analysis of the affecting parameters, such as resin percentage, hardener, and catalyst. The influence of binder content on the moulding qualities of silica sand bound with Alkyd oil urethane binder was investigated. Using a sieve shaker, the experimental materials were sieved and manually blended with the binders. AFS standard test specimens (50 mm diameter by 50 mm height) were prepared using a sand rammer, and four key moulding parameters were determined using a universal sand strength machine, permeability meter, and mould hardness tester: green compression strength (GCS), green shear strength (GSS), permeability, and mould hardness. For the minimal experiments, Box-Behnken experimental matrices were used, and the statistical significance of influencing factors and their interactions will be identified to manage the process. To statistically validate the model, an analysis of variance (ANOVA) test was performed using Minitab. Mold hardness, strength, and permeability will each have their own mathematical equation, which was stated as a nonlinear function of input factors based on experimental input-output data. To optimize the process parameters, a response optimizer (using Minitab) has been used. The results revealed that increasing the resin concentration from 1% to 2% enhances permeability and GSS while decreasing GCS and mould hardness. Hardener was increased from 18 to 20%, which resulted in a drop in permeability and GSS but an increase in GCS and mould hardness. Similarly, increasing the catalyst concentration from 2% to 10% reduces permeability and mould hardness while increasing GCS and GSS.

Experimental investigation on influence of mould wall thickness and hardness on green sand mould permeability

The green compression strength, mould permeability and hardness are the three important properties of the green sand mould. These mould properties are influenced by the sand type, sand grain size, grain shape, clay type, water content, ramming and mould wall thickness. The poor mould permeability and hardness value result in gas related casting defect and poor casting surface finish. Hence in this work, to predict the green sand mould permeability, the exponential models are developed for mould permeability, mould wall thickness and mould hardness value. The mould specimens of 50 mm diameter, 30/40//50/60/70 mm thickness with the hardness value of 87, 90 & 93 are prepared from the moulding sand. The permeability and hardness tests are carried out in the prepared specimens. Using these test results, graphs are plotted between the permeability and mould wall thickness for 87, 90 and 93 hardness values. The exponential model for each hardness value is developed to predict the permeability value for the different mould wall thicknesses.

Reliability based design optimization of casting process parameters using Markov chain model

Foundries in India are facing lower productivity issues due to low quality of castings and wrong practices followed, therein. Minimizing rejection as well as production costs is the key area of concern in these foundries. Casting process parameters are important in the optimization of casting process. In casting process optimization, simulation has become a significant tool used by many researchers/practitioners. Design optimization using reliability has also emerged as a promising tool for optimization, using the probabilistic approach. This approach works on probability of failures through various parameters. Use of reliability-based design optimization (RBDO) in case of casting process optimization can provide some novel results. Markov process is a predictive technique for generation of a stochastic model with sequence of possible events. This research work focused on the development of a Markov chain model for casting failure. Various casting defects, such as cold shut, inclusion, etc. were considered in the study. Process parameters in case of casting process, such as mould hardness and, pouring temperature etc. are also considered. A Markov chain model provides the mapping of various casting failures with casting process parameters. With the probabilities of various process parameters and casting failures, a predictive model for casting process failure can be generated.

Optimization of green sand mould process parameters using Taguchi approach in conjunction with Grey relational analysis

The condition of the mould cavity in sand casting is critical for foundrymen to achieve high-quality castings. Since the last few decades, optimization of green sand mixture has played a critical role in defect minimization. Experiments were carried out in this study using varying percentages (by weight) of sand additions such as water, molasses, bentonite, and fly ash. Green compression strength, permeability, compatibility, and mould hardness have all been tested as a result of the subsequent green sand mould qualities. To tackle this multi-response optimization issue, the Taguchi strategy was used, followed by Grey relational analysis (GRA). An attempt was made to achieve an ideal level of green sand combination process parameters in order to generate the best quality attributes of the green sand mould. The L18orthogonal array design by Taguchi, the Signal-to-Noise (S/N) ratio, and analysis of variance were used to evaluate the effect of chosen green sand mould process factors and their levels on the produced mould qualities. Among the other sand process factors, bentonite was determined to have the greatest effect. Through confirmation trials, a new experiment was undertaken at the ideal parametric combination to forecast and validate increase of quality features. As a result, GRA may be a complete decision-making tool for selecting the proper grade to improve the quality attributes of sand in the foundry business.

Optimization of sand-defects process parameters for reducing its defect using taguchi technique

Foundry or casting manufacturing process is largely used in manufacturing of automobile and general-purpose machine components. Still this method is popular due to low cost, easiness in manufacturing and easy availability of input materials and resources. It involves a number of processes like sand preparation, pattern making, melting, pouring, cooling etc. Due to influence of so many factors defect arises by one factor or many factors. Still trial and error method are used by casting units to remove defects. Therefore, a more disciplined approach is required to find the root cause of problem. In this paper taguchi’s method and design of experiment is used to analyze sand and mould related defects. Standardization (optimization) attempt is done to obtain optimum values of process parameters by taguchi’s method whose experimental approach of design is robust. The parameters affecting the process are chosen as sand grain size, clay content, moisture percentage, pouring temperature, pouring time, green strength, permeability, mould hardness, number of vent holes, number of ramming etc. An orthogonal array L27 is selected which is based on taguchi. In this study a cast iron alloy (FG260) retainer used in tractor is focused.

Utilising Flowability Sensor for Green Sand Mould Characterisation

In this work, an attempt has been made to improve the sand casting process by reducing the percentage of casting defects. The enhancement of the sand casting process is based on producing green sand castings with good pattern profiles and no failures at any complex ‎points during the separation process, handling and transportation. This work ‎introduces modified, non-destructive, direct tests for measuring sand mould ‎properties using sensor readings. ‎A new flowability sensor has been used to measure the time-dependent density, ‎distance-dependent mould hardness, and distance-dependent mould strength. The ‎sensor is able to detect sand motion at the desired points during the mould-making process. The live characterisation of the green sand mould is used to determine the optimum ‎parameters for the compaction process, reduction of the moulding time, and spent ‎energy, so that the cost of the moulding and casting process will be reduced.‎ It has been found that there is a linear relationship between the properties of the green sand samples and the sensor signals. The new method facilitates the measurement of sand properties and determines the most effective moulding parameters based on the flowability sensor readings. The resultant increases in both compactibility and compaction pressure improve mould hardness and mould strength.

Application of batch system ultraviolet light on the surface of kashar cheese, a kind of pasta-filata cheese: effects on mould inactivation, lipid oxidation, colour, hardness and sensory properties.

This research paper addresses the hypothesis that the application of ultraviolet (UV) light before packaging of pasta-filata cheese has the potential to eliminate or control post-processing contamination whilst maintaining chemical and sensorial quality. The surfaces of kashar cheese were treated at different doses of UV light (0.32-9.63 kJ/m2) in a batch UV cabinet system to determine effects on physicochemical and sensorial quality as well as mould inactivation. Untreated cheese samples were also used for comparison. Kashar cheese was naturally contaminated in a mouldy environment to provide the desired mould numbers before UV treatments. Log reductions of 0.34, 0.69 and 2.49 were achieved in samples treated at doses of 0.32, 0.96 and 1.93 kJ/m2, respectively and the mould count of sample treated at 9.63 kJ/m2 was below the detection limit. We found no significant differences in composition and hardness values between any of the treated or control cheeses. Although some individual colour values increased as the UV doses increased, this change was not observed visually in sensory analysis. Increased light intensity accelerated the lipid oxidation causing a perception of off-flavour. The results of this study show that it is necessary to examine the relationship between the oxidative and sensory interactions while determining the effective doses applied to cheese surface for microbial inactivation.

Heat dissipation and inter-relationship between physical properties of moulding sand

The heat dissipation across the moulding sand decides the rate of solidification of castings. For defect free castings, the cooling rate has to be at a preset level. The coarse, medium and fine sand moulds, the properties of the moulding sand like permeability, green compression strength, flowability, compactibility, and mould hardness influence the heat dissipation rate across the mould. An experimental investigation is carried out to understand the influence of these parameters over heat dissipation rate. The grain coarse and fine are found to a major influencing parameter. Analysis of results gives solidification time of Aluminum casting in coarse, medium & fine sand moulding and the inter relationship between physical properties and solidification rate.

Investigations on the suitability of banana peel powder as an alternative additive in synthetic green sand moulding system

ABSTRACT An experimental study focused on the determination of mechanical properties of synthetic green sand system using Nagavali river sand by adding banana peel powder as an additive. Compression strength, shear strength, mould hardness bulk density and permeability are the various properties found in the laboratory following standard testing procedures. Sand aggregate is prepared by mixing the bentonite as binder and banana peel powder as an additive to the silica sand in various amounts. Encouraging results in terms of strength and hardness are obtained by testing the standard sand samples. In fact, the properties exhibited are almost similar to the values obtained by addition of 2% dextrin as an additive to the sand aggregate. Since the banana peel powder can be easily prepared which is most economical in terms of cost compared with dextrin, that can be an alternative additive in preparing the sand moulds to obtain adequate strength and hardness.

Multi-objective optimization of western bentonite (Al2H2Na2O13Si4)-blended green sand casting process parameters to improve mould quality

The quality of the mould in the green sand casting process plays a vital role in achieving good quality castings. In this research work, the mould properties permeability and hardness are focused on to improve the quality of the mould. These properties are improved by optimizing the process parameters such as degrees of ramming, mould wall thickness, and weight percentage of western bentonite using Taguchi-based grey relational analysis. The optimal level of these process parameters is experimentally validated by producing castings in a modern jobbing foundry. In the validation experiments, the moulds are produced with nominal hardness (92) and the mould wall thickness is reduced by creating cavities for storage of gases at a distance of 30 mm from the mould cavity. An interesting result found is that the nominal mould hardness and reduced wall thickness improve the quality of the mould by increasing the permeability value from 80 to 120. The improved mould quality reduces the mould-related casting rejection rate in pressure plate casting from 40% to 30%.

Performance analysis of cow dung as an eco-friendly additive material for sustainable moulding and casting

In the present work, an attempt is made to partially replace high cost silica sand with sustainable eco-friendly cow-dung. The practical utility of cow dung as an additive material that facilitates binding in sand moulds has been tested. The Taguchi method is used to plan and conduct nine experiments with three replicates each. Pareto analysis of variance study is performed to understand the practical significance of moulding sand variables, that is, percentage of cow dung, clay, water, and degree of ramming on sand mould properties. The conflicting multiple objective functions (maximize mould hardness, and minimize collapsibility and gas evolution) are optimized by utilizing the Data Envelopment Analysis Ranking (DEAR) method. The optimal parameters i.e. 6% of clay, 4% of water, 5% of cow-dung and 4 numbers of ramming strokes are obtained by applying a hybrid Taguchi-DEAR method. These parameters show the best moulding properties are: mould hardness 55, gas evolution 5.9 ml·g−1, and collapsibility 470 g·cm−2. Thereafter, a Lovejoy coupling made of aluminium is cast in the sand mould prepared with cow dung and without cow dung, with the optimum set of parameters. The mechanical properties, surface finish, and microstructure of the casting cast with cow-dung are better than that without cow-dung.

Comprehensive modelling, analysis and optimization of furan resin-based moulding sand system with sawdust as an additive

Scarcity of high-cost silica sand, casting defect such as hot tear in hard moulds and casting ejection problem after solidification are the key industrial problems. Sawdust is a by-product of wood working industries, and economic disposal of sawdust in these industries is a growing concern to the wood industries. The present work utilized sawdust as an additive in preparing mould cavity for casting applications. Sand mould properties such as compression strength (CS), mould hardness (MH), gas evolution (GE), permeability (P) and collapsibility (CP) will have good impact on the quality of castings. The effect of variables, namely quantity of resin, hardener, sawdust and setting time, on no-bake furan-bonded sand system is studied in the present research work. The experiments are conducted as per design of experiments, and the data are used to investigate the effect of individual and combined parametric contributions towards responses and establish nonlinear input–output relationships. All nonlinear regression models (that is, input–output relationships) are found to be statistically adequate. The input–output relations are analysed and presented for each of the response with the help of surface plots. Further, the models are found to predict the output close to the experiment (target value). The grand average value in predicting responses is found to be equal to 5.03%. The multi-objective optimization of responses with conflicting nature (minimize: GE and CP; maximize: CS, P and MH) is carried out with the help of global fitness function values determined using genetic algorithm, particle swarm optimization, teacher–learner-based optimization and JAYA algorithms. The optimized values of process parameters that resulted in best set of responses are found to be equal to 60 min, 2.01%, 0.6% and 0.93% for setting time, quantity of resin, hardener and sawdust, respectively. Two automobile coupling parts are cast by pouring molten aluminium into the mould cavity with the optimized and non-optimum sand mould conditions. Further, these two cast components are tested for their quality characteristics, such as surface finish, yield strength, hardness, density and secondary dendrite arm spacing. It has been observed that the quality characteristics of castings produced in mould with optimized parameters are found to be much better.

Application of Taguchi-based Six Sigma method to reduce defects in green sand casting process: a case study

Six Sigma is a systematic method for process improvement. It relies on statistical and scientific methods to reduce the defect rates and achieve improved quality. A case study carried out for a green sand casting manufacturing company. Here, Six Sigma methodology is used for the part: bearing bracket 3809. Define-measure-analyse-improve-control (DMAIC) methodology along with Taguchi method is used to minimise the defects in the bearing bracket 3809. The major tools used in this work are the project charter, process map, statistical graph and cause-and-effect diagram. Use of design of experiment (DOE) and analysis of variance (ANOVA) techniques are combined to determine statistically the correlation of defects with the mould hardness, moisture content, green strength, permeability of sand, pouring rate and pouring temperature and also to find their optimum values needed to reduce/eliminate the defects. The experimental results were statistically analysed and modelled through Taguchi analysis. Based on the findings, the optimised process parameters are taken for experiment and better performance obtained in the production process was confirmed. The comparison between the existing and the proposed process has been attempted in this paper and the results have been discussed in detail.

Study on effect of extrusion of the former tube based on DEFORM-3D

In order to obtain the optimum forming process of the Former tube, two forming schemes were made based on the actual production and processing experience and theory. The two forming schemes were simulated by DEFORM-3D. The optimal forming scheme was determined and the influence of different friction factors and different mould hardness on mould wear and forming load were analyzed; The research results of this paper can provide theoretical guidance for the production and processing of the former tube parts, which can improve the machining quality and precision of the parts, reduce the cost of the test module, and obtain a better shaping effect.

Studies on Porosity of Al-4.5%Cu-2.5pTiB<sub>2</sub> <i>In Situ</i> Composites

In the present paper, experimental investigation as well as computer assisted casting simulation technique is used to analyse the effect of different parameters like properties of sand and molding methods to predict defects in green sand casting. An attempt has been made to obtain the optimal settings of the moulding sand and mould related process parameters for the casting of Al-4.5%Cu-2.5TiB2 composites. The green sand related process parameters considered in the study are moisture content, green compressive strength, permeability of moulding sand and mould hardness. In the fabrication of composites, porosity is greatly influenced due to improper gating/riser system design. The analysis of porosity is performed using Auto-CAST simulation technique by the introduction of a new gating system designed and the solid model was developed for sand mould cavity. A number of iterations using Auto-CAST simulation software were performed for mould filling and solidification analysis to reduce the level and intensities of porosities in cast Al-4.5%Cu-2.5TiB2 composite. With new gating and feeding system design, reduction in porosity and improvement in yield is observed. The simulation results were found to be in good agreement when compared with the experimental trial.

Optimization of green sand mould system using Taguchi based grey relational analysis

The strength of the mould cavity in sand casting is very much significant to attain high-quality castings. Optimization of green sand process parameters plays a vital role in minimizing casting defects. In the present research work, the effect of process parameters such as AFS grain fineness number, water, molasses, bentonite, fly ash, and ramming, and their levels on the resultant mould properties were investigated and optimized using Taguchi based grey relational analysis. The Taguchi L18 orthogonal array and analysis of variance (ANOVA) were used. The quality characteristics viz., green compression strength, permeability, bulk density, mould hardness and shatter index of green sand mould were optimized using grey relational grade, based on the experiments designed using Taguchi's Design of Experiments. ANOVA analysis indicated that water content is the most influential parameter followed by bentonite, and degree of ramming that contributes to the quality characteristics. The results are confirmed by calculating confidence intervals, which lies within the interval limits. Finally, microstructure observations and X-ray diffraction analysis have been performed for the optimal sand parametric combination. Results show that presence of maximum amount of Si02, which might be the reason for enhancement of the physical properties of the sand.

Study of mould hardness for alpha set type resin bonded moulding sand system using Taguchi approach for metal casting applications

The quality of the castings are depended on many properties of sand mould like mould hardness, green compression strength, shear strength etc. and these properties in turn dependent on factors such as grain fineness number of sand, setting/curing time, amount of resin, amount of hardener, moisture content etc. Mould hardness is very important while transferring mould from moulding station to pouring station when the weight of the mould is above 100kg and may lead to defects. In the present work, an effort is made to study the mould hardness of a moulding sand specimen using Taguchi technique.L9 orthogonal array is used and experiments are conducted randomly. The main factors such as the amount of resin, amount of hardener and setting time were considered. Factors were selected based on Literature review and brainstorming session with foundries. The chemical (resin and hardener) used is alphas set type two part system. From experiments, it was observed that the Amount of resin and setting time are significant for mould hardness. Confirmation tests were conducted to validate the obtained results.

Study of mould hardness for alpha set type resin bonded moulding sand system using Taguchi approach for metal casting applications

Study of mould hardness for alpha set type resin bonded moulding sand system using Taguchi approach for metal casting applications