Wyniki wyszukiwania - BazTech

1

Simulation of the Moulding Process of Bentonite-Bonded Green Sand

Abdulamer D., Kaduaw A.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

67--73

EN

Finite Element Method FEM via commercially available software has been used for numerical simulation of the compaction process of bentonite-bonded sand mould. The mathematical model of soil plasticity which involved Drucker-Prager model match with Mohr Coulomb model was selected. The individual parameters which required for the simulation process were determined through direct shear test based on the variation of sand compactability. The novelty of this research work is that the individual micro-mechanical parameters were adopted depend on its directly proportional to the change of sand density during the compaction process. Boundary conditions of the applied load, roller and fixed constraint were specified. An extremely coarse mesh was used and the solution by time-dependent study was done for investigation of material-dependent behaviour of green sand during the compaction process. The research implemented also simulation of the desired points in sand mould to predict behaviour of moulding process, and prevent failure of the sand mould. Distance dependent displacement and distance-dependent pressure have been determined to investigate the effective moulding parameters without spent further energy and cost for obtaining green sand mould. The obtained numerical results of the sand displacement show good agreement with the practical results.

2

Evaluation of automatic vacuum- assisted compaction solutions

Brzeziński M., Wrona R.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 1

113-117

EN

Currently on the mould-making machines market the companies like: DiSA, KUENKEL WAGNER, HAFLINGER, HEINRICH WAGNER SINTO, HUNTER, SAVELLI AND TECHNICAL play significant role. These companies are the manufacturers of various solutions in machines and instalations applied in foundry engineering. Automatic foundry machines for compaction of green sand have the major role in mechanisation and automation processes of making the mould. The concept of operation of automatic machines is based on the static and dynamic methods of compacting the green sand. The method which gains the importance is the compacting method by using the energy of the air pressure. It's the initial stage or the supporting process of compacting the green sand. However in the automatic mould making machines using this method it's essential to use the additional compaction of the mass in order to receive the final parameters of the form. In the constructional solutions of the machines there is the additional division which concerns the method of putting the sand into the mould box . This division distinquishes the transport of the sand with simultaneous compaction or the putting of the sand without the pre-compaction. As the solutions of the major manufacturers are often the subject for application in various foundries, the authors of the paper would like/have the confidence to present their own evaluation process confirmed by their own researches and independent analysis of the producers' solutions.

3

Application of computer simulation methods in the studies of air flows in a vacuum-assisted installation

Ślazyk M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 1

69-72

EN

Vacuum installations are currently used in moulding machines for flaskless as well as for flask moulding processes. The basic aim of using such installation is the improvement of compaction effects due to the intensification of the course of processes in the main compaction method (eg. by shooting) or also realizing of the initial compaction before squeezing. In moulding machines using of this type installations the stable and high compaction state, good imprint of difficult pattern shape are achieved. The low level of noise during the operation of such machines is also the advantage of their using. The correct selection of design and operation parameters of pneumatic moulding machines can be easier with the modeling of air flow process in workspaces of the machine. In the article the mathematical model and example-results of the air flow process simulation in the system of the stand for vacuum assisted moulding investigation have been presented. The simulation results were compared with measurements results of basic parameters describing the course of air flow process.

4

Analysis of Basic Phenomena Occurring in the Vacuum-Assisted Moulding Process

Ślazyk M., Smyksy K.

Archives of Metallurgy and Materials

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2007

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Vol. 52, iss. 3

453-465

EN

Variant of vacuum-assisted moulding process, proposed by the authors, can be used (as the initial stage of moulding) either in new moulding machines or during modernization of existing moulding machines as well. In the article analysis of basic phenomena in the vacuum-assisted moulding process was based on: high speed imaging technique, dynamic air pressure measurements in the working space of the prototype moulding machine, as well as typical compaction effect measurements. The exemplary results of the simulation of the air flow process in the working space of the moulding machine prototype, can be useful in making the proper choice of basic machine parameters.

PL

Proces formowania podciśnieniowego, w wariancie zaproponowanym przez autorów, może być wykorzystany jako wstępny etap zagęszczania, w nowych maszynach formierskich, jak również przy modernizacji użytkowanych maszyn. W artykule przedstawiono analizę podstawowych zjawisk zachodzących podczas formowania podciśnieniowego. Analizę oparto o wyniki badań procesu formowania podciśnieniowego wykorzystujące: technikę szybkiego filmowania, dynamiczne pomiary ciśnienia w przestrzeniach roboczych prototypowej formierki oraz o typowe pomiary efektów zagęszczania. Przedstawiono przykładowe wyniki symulacji procesu przepływu powietrza w przestrzeniach formierki podciśnieniowej, przydatne w doborze podstawowych parametrów maszyny.

5

The influence of the forming process of the special ceramics on its protective abilities

Łukasik W., Dziubak C., Wiśniewski A.

Problemy Techniki Uzbrojenia

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2004

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R. 33, z. 89

15--21

EN

The technological processes to obtain corundum granulate, i.e a raw material for isostatic pressing of protective armour tiles are presented. Two types of the granulate defects which are essential for protective abilities of the tiles are described: a) defective spherical granulate structure that leaves traces of defects in the form of hollow spaces, b) large radial gradient of internal friction manifesting in the density decrease with increasing of overall size of tiles. Improper granulate compaction leads to their individual sintering without creating sufficient strong bonds between granules. In fragments of tiles fired with the projectiles of calibre 12,7 mm and 14,7 mm fracture initiating defects as an effect of the projectile energy are shown. The pictures of the fragments surfaces show characteristic structures (splits). They give evidence of the absorption of large energies. The main mechanical ceramics parameters are attached, which characterize the tendencies linked to the enlargement of the overall size of the tiles.

PL

Przedstawiono procesy technologiczne otrzymywania granulatu korundowego - surowca wyjściowego w prasowaniu izostatytcznym płytek ochronnych do pancerzy. Zaprezentowano dwa typy defektów granulatu, które rzutują na właściwości ochronne płytek: a) zdefektowana struktura kulista granul pozostawiająca ślady defektów w postaci pustych przestrzeni, b) duży gradient promieniowy tarcia wewnętrznego, przejawiający się w zmniejszającej się gęstości wyprasek w funkcji zwiekszających się gabarytów prasowanych płytek. Niedoprasowanie niektórych granul prowadzi do ich indywidualnego spieczenia z rozerwaniem wiązań między sąsiednimi granulami. W odłamkach płytek ostrzelanych pociskami kalibru 12,7 mm i 14,5 mm zidentyfikowano makrowady inicjujące pękanie po wpływem energii pocisku. Zdjęcia powierzchni odłamków wykazują charakterystyczne struktury (odszczepienia) na tych powierzchniach, które świadczą o absorbcji znacznych energii. Przytoczono główne parametry mechaniczne ceramiki, charakteryzujące tendencje przy powiększaniu ogólnych gabarytów płytek.