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1

Technological Properties of Thermo-insulating Moulding Sands with Organic Binder

Stec K., Cholewa M., Kozakiewicz Ł.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

105--110

EN

A thermo-insulating moulding sand with a binder made of aluminosilicate microspheres with organic binder was subjected to testing. The aim of the analysis was to determine selected technological properties of the developed compounds. Compressive strength, friability and gas permeability were determined. The binder content was changed within a range of 5÷20 wt% with a 5% step. The applied matrix is characterized by good thermo-insulating properties and a small size of grains, while synthetic organic binder has favourable functional properties, among which the most noteworthy are the extended life and setting time, good rheological properties as well as high resistance to chemical agents. The intended use of the compound is the casting of 3D CRS (Composite Reinforced Skeletons), which are characterized by a well-developed heat transfer surface area, good absorption of impact energy, low mass and a target thickness of connectors within a range of 1.5÷3 mm. The construction of 3D CRS castings is an original concept developed by the employees of the Department of Foundry Engineering at the Silesian University of Technology.

2

Modelling of the material destruction of vertically arranged honeycomb cellular structure

Piekło J., Małysza M., Dańko R.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1300--1308

EN

The paper presents the results of the experimental and numerical analysis of material destruction of honeycomb cellular structure. Based on the experimental research, the results of numerical calculations regarding the compression process were verified along with the correctness of used constitutive numerical model. The destruction was analyzed for the casting with no structural defects and for the casting with detected porosities. The results were compared to the structural strength of the honeycomb structure manufactured on the CNC machine. The metallic honeycomb structure was manufactured as a casting of Al alloy in the investment casting technology. For manufacturing purposes the honeycomb model was obtained in additive manufacturing process. The castings and the CNC honeycomb were used in the compression test trials. The process was controlled by the displacement and the results were registered as the changes of the height and the force value. Based on the experimental results the numerical model of honeycombs was introduced for the numerical analysis of the energy absorption and compression process. The results showed good correlation between the experiment and FEM (Finite Element Method) analysis.

3

Methods of Additive Manufacturing used in the Technology of Skeleton Castings

Piekło J., Maj M.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 2

699--702

EN

Rapid development of the methods of additive manufacturing (AM) introduces a number of changes to the design of foundry equipment. AM methods are of particular importance in the development of technology to make small lots of castings or single cast items of complex shapes, such as skeleton castings manufactured also by means of other technologies [1]. AM methods create the possibility of making single-use moulds, cores and wax patterns, as well as patterns made from plastics for repeated use. The development of AM techniques gives theoretically unlimited possibilities in the choice of the designed casting configurations. This fact can be used during the analysis of casting mechanical properties based on the methods of topology optimisation [2], [3], [17], when the said optimisation carried out at the initial stage of design ”matches” the shape of parts to the field of stresses or displacements caused by external load and fixing mode. The article discusses the possibilities and advantages that result from combining the new methods of shaping the casting endurance with AM technologies.

PL

W artykule zaprezentowano możliwości integracji nowoczesnych technologii wykonania oprzyrządowania odlewniczego oraz metod optymalizacji konstrukcji. Systemy przyrostowego wytwarzania (ang. additiv manufacturing, AM) pozwalają na projektowanie bardzo złożonych kształtów konstrukcji, spełniających w znacznie większym stopniu, niż inne metody technologiczne, kryteria kształtowania wytrzymałościowego. Niektóre z szerokiej gamy metod AM, omówione w niniejszym artykule, są szczególnie przydatne w wytwarzaniu form i rdzeni ceramicznych oraz metalowych części oprzyrządowania odlewniczego. Omówiono zastosowanie metod optymalizacji topologicznej w kształtowaniu konstrukcji we wczesnej fazie projektowania, szczególnie w tym przypadku, gdy określone są jedynie założenia dotyczące funkcjonowania podparć i sił działających na obiekt. Przykłady optymalizacji wykonano w oparciu o własny algorytm obliczeniowy, który umożliwia przemieszczanie i eliminowanie masy wewnątrz obszaru projektowego, tak aby przy określonych warunkach brzegowych i sposobie obciążenia, otrzymać najbardziej korzystny stosunek wytrzymałości do masy odlewu. Z reguły w wyniku zastosowania powyższego algorytmu powstają konstrukcje o złożonym kształcie - przestrzenne ramy lub kratownice oraz powierzchnie nie dające się opisać za pomocą prostych jednostek geometrycznych, dla których wykonania właściwe jest stosowanie przyrostowych metod wytwarzania oprzyrządowania odlewniczego.

4

Heat-insulating moulding sand with the glycol addition

Cholewa M., Szuter T.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3

61-64

EN

The article presents a selection of the composition and basic properties of highly insulating moulding sand. Sandmix is designed especially for thin-walled castings with high tendency to oxidation - particularly in spatial cores skeleton castings. An example of matrix of sandmix are aluminosilicate microspheres and the binder is bentonite plasticized with water and polyglycol. By using the microspheres high insulation, high mechanical strength and low specific weight core sand was obtained. Addition of polyglycol improved the mechanical properties, deformation characteristics, surface smoothness and reduced friability of sandmix.

5

Geometrical and mechanical analysis of 3D casted skeleton structure

Cholewa M., Szuter T.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 2

23--26

EN

The article presents selection of the geometry of engineering casted skeleton structure using the analysis of the stress state of structural variants. The main criterion for selection was using the simplest geometry of casting techniques for the manufacturing of the skeleton castings. Preliminary simulations of stress in the casting virtual. Analyses were carried out in an ANSYS Multiphysics environment. Macrostructure of casting were selected for testing on the actual model.

6

Numerical simulation of pouring and solidification of closed skeleton casting

Cholewa M., Dziuba-Kałuża M.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 3s

9-12

EN

In this work authors showed results of simulation manufacturing closed skeleton casting. The aim of conducted simulations was the choice of thermal and geometrical parameters for the needs of designed calculations of the skeleton castings and the estimation of the guidelines for the technology of manufacturing. During simulation effect at mould filling process for the skeleton casting was analyzed. Analysis of temperature distribution and analysis of solidification closed aluminium skeleton casting were conduced. It was confirmed that the metal is flows at the external surfaces and fills internal channels of skeleton, until the moment of overall filling of the mould. Whole casting is solidification in finish of pouring mould. It is advantageous by reasons of satisfactory mould filling. Part of casting which was connected with feeder, on upper surface of casting solidified the slowest. in consequence to the lowest heat give up.