Advances in technology of soluble cores for die castings

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.Web of Science152342

INCREASING LABOUR PRODUCTIVITY OF A POWDERED PAINT SHOP IN THE FACTORY SECO GROUP, a.s. JIČÍN

47 s. :obr., tab., grafy +CD ROMPředmětem této bakalářské práce je zvýšení produktivity práce práškové lakovny ve společnosti Seco Group a.s. Jičín. Dělí se na teoretickou a praktickou část. Teoretická část práce popisuje současný stav povrchové úpravy dílů malotraktorů. V druhé části, té praktické, se zabývá návrhem vhodného opatření změny procesu lakování s cílem zvýšení produktivity prác

Water-soluble cores – verifying development trends

Application of pure inorganic salt-based cores has been known since the end of the 20th century, especially in the field of gravity and low-pressure die casting. The contemporary trend in technology leads to the use of the cores in the field of non-ferrous-alloy high-pressure die casting. The main methods of the core production include high-pressure squeezing and shooting (warm core box). During research processes it was shown that pure-salt application is not very suitable for high-pressure casting. That is why a composite salt-based matrix of defined properties was started to be used. The aim of the paper is to verify the influences of the chemical composition, shape and morphology of the grains of various NaCl compounds on the mechanical properties (the bending strength) of water-soluble salt cores used for Al-alloy high-pressure die casting and to evaluate their properties resulting from the squeezing and shooting methods.Web of Science491676

Prostorové modelování báze dubňanské sloje v moravské ústřední prohlubni (česká část Vídeňské pánve)

This paper deals with the methodology of modelling the Dubňany lignite seam base and its tectonic failure. Tectonic pattern of the Vienna Basin has been subject of many studies. Opinions on its origin have been developing. Coal seams in the South Moravian Lignite Coalfield were modelled under the project of the example modern evaluation of the coal deposit. Designed software with application of modern mathematical, statistical and geostatistical methods and SURFER program were used for coal seam modelling. Input data were taken from detailed mining, deposit and well exploration carried out for more than 50 years.Příspěvek je věnován metodice digitálního modelování báze dubňanské lignitové sloje a jejího tektonického porušení. Tektonická stavba vídeňské pánve je předmětem mnoha studií a názory na její genezi se stále vyvíjejí. Podrobné modelování slojí jihomoravského lignitového revíru bylo provedeno v rámci vzorového komplexního hodnocení uhelného ložiska v prostředí programu SURFER a pomocí účelově sestaveného programového systému s využitím moderních matematických, statistických a geostatistických metod. Vstupní data tvořily údaje o sloji a jejím okolí získané v minulosti během více než padesátiletého podrobného důlního, ložiskového a vrtného průzkumu

Development of foundry cores based on inorganic salts

The aim of this study is to describe the possibilities of using salt cores for gravity, low-pressure or high-pressure die-casting technology. Determinations of the primary, secondary and final residual strengths were carried out in order to evaluate the possibilities of the salt-core utilization. Furthermore, this contribution is focused on developing composite salts with better mechanical properties. The solubility of these cores and a possibility of their reclamation in a closed cycle with positive impacts on the environment were also studied.Web of Science47669368

Razvoj kompozitnih slanih jeder za uporabo v livarstvu

For the purpose of increasing the physical/mechanical properties of the cores based on inorganic salts generally destined for pre-casting the cavities and holes of the castings from non-ferrous alloys, the composite salt matrixes are preferably used. The base salt is enriched with the materials of defined properties (granulometry, heat resistance, cooling effect, heat conductivity). This contribution aims at determining the influences of individual additives on the behaviour of the cores prepared with different methods (shooting and squeezing) during a production of the castings with a high surface quality of the pre-cast holes.Zaradi nara{~ajo~ih fizikalno-mehanskih lastnosti jeder na osnovi anorganskih soli se za jedra, najpogosteje namenjena za predhodno litje votlin in praznin v ulitkih iz ne`eleznih zlitin, uporabljajo kompoziti z osnovo iz soli. Osnovna sol je obogatena z materiali z dolo~enimi lastnostmi (zrnatost, toplotna odpornost, u~inek ohlajanja, toplotna prehodnost). Namen tega prispevka je dolo~iti vpliv posameznih dodatkov na vedenje jeder, pripravljenih po razli~nih metodah (s streljanjem in z brizganjem) med izdelavo ulitkov z veliko kvaliteto povr{ine in predizdelanih odprtin.Web of Science49462361

Alternative evaluation of the properties of the silica sands

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).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.Web of Science59273873

The application of morphostructural analysis and its validation by comparison with documented faults within the Zlate Hory ore district (the Northeastern part of the Bohemian Massif)

The goal of this study is to determine the validity of morpholineaments network that was inferred based on morphostructural analysis of digital elevation model (DEM), by crosschecking with documented faults. The test field has been spread over the exploitation areas in the Zlaté Hory ore district. Various morphometric analyses such as slope, aspect, first directional derivative, gradient operator, combination of altitude and shaded relief, were chosen as particular tools of the morphostructural analysis. The results of each analysis were compared with the results of structural-tectonic mapping. The inferred morpholineaments network was compared with mining maps of the scale 1:500, which provide detailed information about tectonic deformation of rock massif in the area of interest and were used to image fault traces on the surface. The validity of inferred morpholineaments network was determined by authorized software SROV_TEKT, developed by the authors. The morpholineaments network resulting from the morphostructural analysis and tested by this software overlaps at 83 % of the documented main faults in the mines.Web of Science10117

Dynamic modelling of kaolin deposits on example of the Jimlíkov-East deposit

This paper focuses on research within the project TE02000029 Competence Centre for Effective and Ecological Mining of Mineral Resources, granted by The Technology Agency of the Czech Republic, and, more specifically, on the research within its work package WP4 – Spatial modelling of mineral deposits. The focus of this work package is digital modelling of selected non-energetic raw materials, which belong to the critical commodities, as defined by the European Union. For modelling these deposits, suitable mathematical procedures, based on study and re-evaluation of archived data, are needed. One of the selected deposits is a kaolin deposit near the village Jimlíkov near the city Karlovy Vary. In this paper, we show a step-by-step procedure for creation, visualization and evaluation of a 3D model of the deposit. This methodology, along with our recently developed soft ware allows a user to create a variant of this dynamic model for the same or similar types of deposits, enables rapid updating of these models when adding or changing the input data on the basis of new mining exploration or when changing modelling parameters, such as using multiple variations interpolation parameters. Our methodology leads to a more advanced deposit evaluation, including adaptive estimates of the reserves based on the usability requirements we choose.This paper focuses on research within the project TE02000029 Competence Centre for Effective and Ecological Mining of Mineral Resources, granted by The Technology Agency of the Czech Republic, and, more specifically, on the research within its work package WP4 – Spatial modelling of mineral deposits. The focus of this work package is digital modelling of selected non-energetic raw materials, which belong to the critical commodities, as defined by the European Union. For modelling these deposits, suitable mathematical procedures, based on study and re-evaluation of archived data, are needed. One of the selected deposits is a kaolin deposit near the village Jimlíkov near the city Karlovy Vary. In this paper, we show a step-by-step procedure for creation, visualization and evaluation of a 3D model of the deposit. This methodology, along with our recently developed soft ware allows a user to create a variant of this dynamic model for the same or similar types of deposits, enables rapid updating of these models when adding or changing the input data on the basis of new mining exploration or when changing modelling parameters, such as using multiple variations interpolation parameters. Our methodology leads to a more advanced deposit evaluation, including adaptive estimates of the reserves based on the usability requirements we choose