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 mould...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 cowdung.展开更多
The patternless casting manufacturing (PCM) technique, which adopts a new concept of double scanning method, combines the principle of discreteness and deposition with resin-bonded sand technique. This paper is to eva...The patternless casting manufacturing (PCM) technique, which adopts a new concept of double scanning method, combines the principle of discreteness and deposition with resin-bonded sand technique. This paper is to evaluate the dimensional accuracy of sand mould on PCM. The two important factors—the liquid penetration rule in the space of particles and the shape and dimension of the agglomeration unit body, which influence the process parameters such as scanning speed, layer thickness, liquid flux on dimension accuracy, and surface qualities, were investigated systematically, thus the theoretical basis for these parameters was provided. Experiments on rapid manufacturing of sand mould were carried out, and the results of the free penetration and the constraint penetration well verified the relationship of the two factors and the process parameters.展开更多
This paper presents a technique for controlling the pressure of a molten metal when using a new type of iron casting method called sand mold press casting to realize high productivity and obtain high-quality products....This paper presents a technique for controlling the pressure of a molten metal when using a new type of iron casting method called sand mold press casting to realize high productivity and obtain high-quality products.The past test results using this method showed a casting yield of 90% to 95%,while conventional methods only show a casting yield of 60% to 70%.Although the press casting method does not require a sprue cup or runner channel casting defects such as metal penetration are often caused by the high pressure in the high-velocity pressing part of this casting process.Therefore,we proposed a pressure control method with a mathematical model of molten metal pressure,and with it we achieved experimental confirmation of the successful production of brake drums at different pressing temperatures.Results show that the proposed pressing control method can realize sound,penetration-free casting production.However,the theoretical analysis and design of this pressing process had not previously been studied sufficiently,and therefore this paper presents the theoretical design algorithm for the process as well as its experimental confirmation.展开更多
文摘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 cowdung.
基金Supported by the Technology Research and Development Program of Hebei Province, China (No. 07212131)
文摘The patternless casting manufacturing (PCM) technique, which adopts a new concept of double scanning method, combines the principle of discreteness and deposition with resin-bonded sand technique. This paper is to evaluate the dimensional accuracy of sand mould on PCM. The two important factors—the liquid penetration rule in the space of particles and the shape and dimension of the agglomeration unit body, which influence the process parameters such as scanning speed, layer thickness, liquid flux on dimension accuracy, and surface qualities, were investigated systematically, thus the theoretical basis for these parameters was provided. Experiments on rapid manufacturing of sand mould were carried out, and the results of the free penetration and the constraint penetration well verified the relationship of the two factors and the process parameters.
文摘This paper presents a technique for controlling the pressure of a molten metal when using a new type of iron casting method called sand mold press casting to realize high productivity and obtain high-quality products.The past test results using this method showed a casting yield of 90% to 95%,while conventional methods only show a casting yield of 60% to 70%.Although the press casting method does not require a sprue cup or runner channel casting defects such as metal penetration are often caused by the high pressure in the high-velocity pressing part of this casting process.Therefore,we proposed a pressure control method with a mathematical model of molten metal pressure,and with it we achieved experimental confirmation of the successful production of brake drums at different pressing temperatures.Results show that the proposed pressing control method can realize sound,penetration-free casting production.However,the theoretical analysis and design of this pressing process had not previously been studied sufficiently,and therefore this paper presents the theoretical design algorithm for the process as well as its experimental confirmation.
