Wyniki wyszukiwania - Biblioteka Nauki

1

Application of Non-Silica Sands for High Quality Castings

100%

Beňo J. , Poręba M. , Bajer T. , Beňo J. , Poręba M. , Bajer T.

|

nr 1

2

Investigation of the cusp height when ball-end milling from shaped surfaces

94%

Stahovec J. , Beňo J. , Vrabel' M.

|

2013

|

tom z. 85[288], nr 2

187--196

EN

This paper presents a model for cusp height in the ball-end milling process. In many milling operations, the cutting tool performs step over and makes adjacent cuts to complete machining of any feature. As a result, a small cusp of material, called a cusp height, will remain between these cuts on the surrounding walls or on the machined surface if a ball-end mill is used. This procedure presents application of software to evaluate cusp height in milling process. The height of cusp is examined in surfaces having different curvature ratio and different orientation. The model for the mathematical prediction of the cusp height has been developed in terms of axial and radial depth of cut, surface curvature and tool diameter. The application of the DOE technique by Taguchi gives the process parameter values that lead to the minimum machining time and achievement of the desired surface texture.

PL

W pracy przedstawiono model wysokości śladu obróbkowego w procesie obróbki frezem palcowym o zarysie kulistym. W wielu operacjach frezowania narzędzie wykonuje stopniowe ruchy, tworząc przylegające do siebie ślady obróbkowe. W rezultacie, jeżeli obróbka odbywa się frezem palcowym o zarysie kulistym, po obróbce pozostają małe występy materiału na krawędziach sąsiednich śladów obróbkowych. Procedura ta przedstawia zastosowanie oprogramowania do oceny wysokości zarysu śladu obróbkowego w procesie frezowania. Wysokość występów jest badana na powierzchniach mających różny wskaźnik krzywizny i różną orientację. Opracowano matematyczny model do przewidywania występów obróbkowych w odniesieniu do osiowych i promieniowych głębokości skrawania, krzywizny powierzchni i średnicy narzędzia. Zastosowana technika DOE Taguchiego wyznacza wartości parametrów procesu, które prowadzą do najkrótszego czasu obróbki i osiągnięcia pożądanej tekstury powierzchni.

3

Advances in Technology of Soluble Cores for Die Castings

94%

Jelínek P. , Adámková E. , Mikšovský F. , Beňo J.

Archives of Foundry Engineering

|

2015

|

tom Vol. 15, iss. 2

29--34

EN

A number of technologies is developed that substitute simple metal cores in the high-pressure casting technology. Soluble cores, namely on the salt basis, represent the highest prospect. The contribution gives the results of the production of salt cores by high-pressure squeezing and shooting with using a binder. Special attention is paid to the shape of NaCl salt crystals with additives and the influence on strength properties of cores. A technology of bonding the salt cores is developing. Salinity of circulating water is studied and it is checked with the aid of electrical conductance.

4

Influence of Silica Sand on Surface Casting Quality

94%

Beňo J. , Adamusová K. , Merta V. , Bajer T.

|

2019

|

tom iss. 2

5--8

EN

The current casting production of castings brings increased demands for surface and internal quality of the castings. Important factors, that influence the quality of casted components, are the materials used for the manufacture of moulds and cores. For the preparation and production of moulds and cores, in order to achieve a low level of casting defects, then it used a high quality input materials, including various types of sands, modified binders, additives, etc. However, even the most expensive raw materials are not a guarantee to achieve the quality of production. It is always necessary to choose the appropriate combination of input material together with an appropriate proposal for the way of the production, the metallurgical treatment of cast alloy, etc. The aim of this paper is to establish the basic principles for the selection of the base core mixtures components – sands to eliminate defects from the tension, specifically veining. Various silica sand, which are commonly used in foundries of Middle Europe region, were selected and tested.

5

Efficiency of additives of the polysaccharide type on physical properties of bentonite mixtures

94%

Beňo J. , Jelínek P. , Špirutová N. , Mikšovský F.

|

2011

|

tom Vol. 11, iss. 1

5-8

EN

The addition of polysaccharide additives generally aims at improving some important physical properties of bentonite mixtures, above all the stability of moulds against the water loss and prevention of surface defects of castings. Polysaccharide products of inland and foreign production were checked in mixtures of two bentonites of the Czech provenance with the same montmorillonite content. The attention was paid in particular to the abrasion resistance of mixtures during storing them under constant climatic conditions. Conclusions have shown the substantial influence of: the amount of the added additive, the kind and structural composition of the additive (pH of the water extract, electric conductance).

6

Surface quality of foundry pattern manufactured by FDM method - rapid prototyping

94%

Hanus A. , Špirutová N. , Beňo J.

|

tom Vol. 11, iss. 1s

15-20

EN

The goal of this paper was to verify the possibilities of using 3D models produced by means of the FDM technology for actual foundry production. Experimental models were produced using Dimension sst 768 3D printer. Two types of castings (type I - simple plates, type II - jewellery) were cast in plaster moulds. The models were burnt out at 500 oC. The goal of the experiment was to verify the effect of modifications upon surface quality of the resulting casting. The ABS model was tested with unmodified surface, chemically treated surface, blasted surface and blasted and etched surface together. The results of the experiment have confirmed the assumed effect of both mechanical and chemical modifications of the model surface on casting surface quality.

7

Reclamation of Self-Setting Mixtures with Olivine Bound with Alkaline Resols

94%

Jelínek P. , Beňo J. , Duda J. , Mikšovský F.

|

8

Reclamation of self-setting mixtures with olivine bound with alkaline resols

94%

Jelínek P. , Duda J. , Mikšovský F. , Beňo J.

|

tom Vol. 12, iss. 1

47-52

EN

For the reasons of environmental problems connected with the use of furan binders the attention is increasingly paid to self-setting mixtures with alkali resols. A resol binder stabilized with KOH, NaOH is hardened by liquid esters with the formation of alkaline salts. The increase of their concentration affects the shortening of the mixture bench life, it decreases strength, abrasive wear of moulds and cores is growing, and it results in uneconomical dilution of the reclaim with expensive new base sand. Length of life (bench life) of mixtures plays an important role just in manufacture of huge and voluminous moulds and cores in self-setting mixtures. This contribution aims at analyzing the function of reactive alkaline salts in the reclaim, it monitors consequences of its thermal exposure on properties of self-setting mixtures, and it deals with development of methods evaluating its qualities.

9

Dilatometric characterization of foundry sands

94%

Břuska M. , Beňo J. , Cagala M. , Jasinková V.

|

tom Vol. 12, iss. 2

9-14

EN

The goal of this contribution is summary of physical - chemistry properties of usually used foundry silica and no - silica sands in Czech foundries. With the help of dilatometry analysis theoretical assumptions of influence of grain shape and size on dilatation value of sands were confirmed. Determined was the possibility of dilatometry analysis employment for preparing special (hybrid) sands with lower and/or more linear character of dilatation.

10

Influence of Silica Sand on Surface Casting Quality

84%

Beňo J. , Adamusová K. , Merta V. , Bajer T. , Beňo J. , Adamusová K. , Merta V. , Bajer T.

|

nr 2

11

Gas Evolution of GEOPOL® W Sand Mixture and Comparison with Organic Binders

83%

Vykoukal M. , Burian A. , Přerovská M. , Bajer T. , Beňo J.

|

nr 2

12

The Measurement of High-Temperature Expansion as the Standard of Estimation the Knock-Out Properties of Moulding Sands with Hydrated Sodium Silicate

83%

Major-Gabryś K. , Dobosz S. M. , Jelínek P. , Jakubski J. , Beňo J.

|

2014

|

tom Vol. 59, iss. 2

739--742

EN

The necessity of receiving high quality castings forces undertaking research to elaborate moulding and core sands ensuring obtaining the materials with relevant technological parameters and also with high environmental standards. The most important group here are moulding sands with hydrated sodium silicate. Unfortunately, their fundamental disadvantages are weak knock-out properties. The article presents the most commonly used methods of measuring the knock-out properties of moulding and core sands. The authors propose a new method for estimation this parameter. The method is based on the measurement of high-temperature expansion.

PL

Potrzeba uzyskiwania wysokiej jakości odlewów wymusza podejmowanie prac badawczych dla otrzymania mas formierskich i rdzeniowych zapewniających uzyskanie tworzyw o odpowiednich parametrach technologicznych, jednocześnie spełniających wysokie wymogi ochrony środowiska. Najważniejszą grupę stanowią tutaj masy z uwodnionym krzemianem sodu. Niestety jedną z ich podstawowych wad jest słaba wybijalność. W artykule zostały przedstawione najczęściej stosowane metody pomiaru wybijalności mas formierskich i rdzeniowych Autorzy zaproponowali nową metodę oceny wybijalności opierającą się na pomiarze ekspansji wysokotemperaturowej.

13

Alternative Evaluation of the Properties of the Silica Sands

83%

Beňo J. , Mikšovský F. , Jelinek P. , Konečná K. , Smysl P.

|

2014

|

tom Vol. 59, iss. 2

735--738

EN

For the evaluation of silica sands, which belongs to the most employed sands of foundry molding mixtures, there are a number of methods and techniques to characterize their quality. This implies good knowledge of their strengths and weaknesses. However, a small proportion of published results are dedicated to the impact of transport on transport routes in the foundry and the processes of dry reclamation on the properties of the silica sands, in particular on changes to the granulometry and the formation of undesirable dust sands shares, which significantly affect the properties of the sand mixture. The aim of this contribution is the evaluation of inclination of the silica sand to crush (the formation of dust, change the granulometry) according to the newly developed methodology with regard to its nature of sand (genesis, the shape of the grains, the character of the surface).

PL

Piaski kwarcowe stanowią podstawowe tworzywo na osnowę mas formierskich i rdzeniowych. Stąd istnieje bardzo wiele metod charakteryzujących ich jakość, co umożliwia poznanie ich zalet i wad. Mało jest jednak prac opisujących wpływ systemów transportowych odlewni oraz systemów suchej regeneracji mas na zmianę ich składu granulometrycznego oraz zawartości frakcji pylastych na właściwości mas. Celem niniejszej pracy jest ocena skłonności piasku kwarcowego do rozkruszania, (tworzenia frakcji pyłowych i zmianie granulometrii) według nowo opracowanej metodyki uwzględniającej charakterystyczne cechy piasku wynikające z jego pochodzenia, kształty ziaren i charakteru powierzchni.

14

Influence green sand system by core sand additions

83%

Špirutová N. , Beňo J. , Bednářová V. , Kříž J. , Kandrnál M.

|

tom Vol. 12, iss. 1

105-110

EN

Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron) are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: 'How the green sand systems are influenced by core sands?" This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50%. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition). Ratio of active betonite by Methylene blue test was also determined.

15

Measurement of Molding Sand Elasticity

71%

Major-Gabryś K. , Grabarczyk A. , Dobosz S. M. , Jakubski J. , Morek J. , Beňo J.

|

2018

|

tom Vol. 2, no. 2

38--44

EN

The progressive mechanization and automation of industrial equipment is the driving force of progress, not only in the field of production but also in the measuring and control equipment. In mold production, the automation of processes such as forming molds and cores along with their assembly has led to increases in serial production, reductions in defects, and the shortening of molding times, among others. Thanks to automation in mold and core departments and the use of all sorts of manipulators, mold production in foundries has gained momentum. Unfortunately, in addition to the mentioned advantages, there are also new challenges as to the quality and properties of the molding and core sands used in highly automated foundries.This article presents recent research on molding sand elasticity. The topic was introduced as an attempt to answer the new needs of highly mechanized foundries. The article discusses a new method of measuring the resistance of molding materials to undergoing mechanical deformation (molding sand elasticity), with an additional analysis of the bending strengths of the tested samples. Precise measurements, test sample preparation, and interpretation of the received results are presented in the article.

16

Mechanical Properties of Two Manganese Steels

71%

Cagala M. , Lichý P. , Beňo J. , Mazancová E. , Břuska M. , Špirutová N.

|

17

Mechanical properties of two manganese steels

71%

Cagala M. , Mazancová E. , Lichý P. , Beňo J. , Břuska M. , Špirutová N.

|

tom Vol. 12, iss. 1

9-12

EN

The article is focused on thermomechanical and plastic properties of two high-manganese TRIPLEX type steels with an internal marking 1043 and 1045. Tensile tests at ambient temperature and at a temperature interval 600 C to 1100 C were performed for these heats with a different chemical composition. After the samples having been ruptured, ductility was observed which was expressed by reduction of material after the tensile test. Then the stacking fault energy was calculated and dilatation of both high-manganese steels was measured. At ambient temperature (20 C), 1043 heat featured higher tensile strength by 66MPa than 1045 heat. Microhardness was higher by 8HV0,2 for 1045 steel than for 1043 steel (203HV0,2). At 20 C, ductility only differed by 3% for the both heats. Decrease of tensile properties occurred at higher temperatures of 600 up to 1100 C. This tensile properties decrease at high temperatures is evident for most of metals. The strength level difference of the both heats in the temperature range 20 C up to 1100 C corresponded to 83 MPa, while between 600 C and 1100 C the difference was only 18 MPa. In the temperature range 600 C to 800 C, a decrease in ductility values down to 14 % (1045 heat), or 22 % (1043 heat), was noticed. This decrease was accompanied with occurrence of complex Aluminium oxides in a superposition with detected AlN particles. Further ductility decrease was only noted for 1043 heat where higher occurrence of shrinkage porosity was observed which might have contributed to a slight decrease in reduction of area values in the temperature range 900 C to 1100 C, in contrast to 1045 heat matrix.