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• Investigation of the Granulometric and Mechanical Properties of Inorganic Used Sand

  302-308

  Viktória Dargai

  László Varga

  Views:

  175

  This paper examines the use of a modified inorganic binder in metal-alloy casting. The results of investigations regarding the effect of reusing the used sand multiple times without reclamation. The technological properties of silica sand with inorganic binders were presented, two different temperatures were applied to make the used sands. After lump crushing the inorganic used sand was recycled in order to make a new sand mixture. Our work was focused on the effect of multiple usage of inorganic used sands on the mechanical and granulometric properties prepared with modified inorganic binder.

• Analysis of a Special, 3D Metal-Printed HPDC Tool Material

  251-265

  Sándor Endre Kovács

  László Varga

  Zsolt Szentes

  Views:

  190

  High Pressure Die Casting (HPDC) is still the most productive metal-casting method of our time, however the more demanding are the industrial expectations, the more challenging it becomes to ensure the creation of the difficult cavity geometries and the thermal balance of the die-cast tool. New perspective is required, thus we can utilize high heat-conductivity tool steels and additive manufacturing technology.

• Effect of the Changes in Bulk Density and Granulometric Properties on the Strength Properties of the Moulding Sand Mixtures

  116-122

  Henrietta Hudák

  László Varga

  Views:

  189

  Foundry technology uses a lot of several natural materials. Sands use for preparing mixtures whereby making moulds or cores. Sand is defined as a granular, refractory major portion of mixture (90 – 98% in dependence on used binder). Sand properties depend on it has chemical and mineralogical composition; mainly particle size distribution and shape of grains and its size and sand surface texture. A comparative measurement of two quartz sand with different surface quality was carried out. Greensand mixtures were prepared to measure their permeability, compressive strength and wet tensile strength. The strength of sand mixtures has two main components. One of them is the cohesion of the binder; the other one is the adhesion between the binder and the foundry sand. The aim of this research is to determine the ratio of cohesion and adhesion within the strength values.

• Ultrasonic Powder Atomization for Additive Manufacturing

  69-75

  David Halapi

  László Varga

  Views:

  198

  The following article presents a special case of metal powder production, ultrasonic metal atomization. In this case, ultrasound technology is based on the capillary wave phenomenon. We verify the suitability of the produced powders for 3D metal printing with various tests. In the case of prints with a metal powder bed fusion (PBF), the properties of the raw material of the powder are extremely important. The main results of the tests carried out in the article (SEM images, EDS composition analysis, sieve analysis) were described.

• The Pressure Characteristics of the Released Gases from Sand Cores

  73-79

  Laura Johanna Mádi

  Imre Budavári

  László Varga

  Views:

  157

  The core packages used for the production of castings are generally made from cores of different quality (no- bake phenol, HB-phenol, and HB-furan) and resin quantity, to meet the various requirements for the casting. In our research, the effect of the amount of resin on the pressure of the gases evolved from the cores was investigated. Experiments have shown that increasing the amount of resin has a different effect on different binder systems.

• Application of Additive Technology in Precision Casting

  43-56

  Dávid Halápi

  László Varga

  Views:

  197

  In this paper the surface of the prepared test specimens had been examined with light microscopy and surface roughness measurements. In order to improve the surface smoothness of PLA specimens, application of ethyl acetate was required. After this surface treatment, microscopic images were taken again. The melting and decomposition temperatures of the materials had been determined using derivatography. The chosen method was precision casting with gypsum molding. Also, the plaster molds had been burnt out according to the predefined melting and firing diagram. The measurement series shows that the samples produced by 3D printing can also be used in the field of precision casting. They provide greater freedom of design, more sophisticated pieces, and prototypes can be finished in a shorter amount of time.

• Mechanical Testing of 3D Metal Printed Stainless Steel Specimens

  7-13.

  Sándor Endre Kovács

  László Varga

  Views:

  117

  Additive manufacturing (AM) is a cutting-edge production method, which has come a long way since its first introduction in the ’80s. Back in the days its usage was very limited to stereolithography, and was only able to make weak structures, so it only worked for visualization. Four decades later it is one of the leading research fields in production areas, because of its flexibility and its ability to make almost any complex geometry. However, no matter how powerful it is, it is not omnipotent, there are certain size and shape restrictions even this method must apply to.