As a part of this work, an analysis of the current state of knowledge regarding the use of additive technology - binder jetting in the production of castings was made. The binder jetting (so-called 3D printing) has become the leading method of sand mold and core production. Within this paper types of molding and core sands with organic and inorganic binders that are and can be used in technology were analyzed. The need to carry out works aimed at developing pro-ecological molding / core sands with inorganic binders and organic binders with reduced harmfulness to the environment dedicated to binder jetting technology was noticed. The influence of technology parameters on the properties of molding / core sands and the properties of cast components was analyzed. It was shown that thanks to the unlimited shapes of the systems obtained with the use of additive technologies, it is possible to influence the rate of heat dissipation through the mold, which positively effects the process of solidification and crystallization of the castings.
This paperwork is focused on the quality of AlSi6Cu4 casting with different wall thicknesses cast into the metal mold. Investigated are structural changes (the morphology, size, and distribution of structural components). The quantitative analysis is used to numerically evaluate the size and area fraction of structural parameters (α-phase, eutectic Si, intermetallic phases) between delivered experimental material and cast with different wall thicknesses. Additionally, the Brinell hardness is performed to obtain the mechanical property benefits of the thin-walled alloys. This research leads to the conclusion, that the AlSi6Cu4 alloy from metal mold has finer structural components, especially in small wall thicknesses, and thus has better mechanical properties (Brinell hardness). These secondary Al-castings have a high potential for use in the automotive industry, due to the thin thicknesses and thus lightweight of the construction.
Nowadays, the best castings’ manufacturers have to meet very demanding requirements and specifications applicable to mechanical properties and other characteristics. To fulfill those requirements, more and more sophisticated methods are being used to analyze the internal quality of castings. In many cases, the commonly used Non-Destructive Methods, like X-ray or ultrasonic testing, are not enough to ensure precise and unequivocal evaluation. Especially, when the properties of the casting only slightly fail the specification and the reasons for such failures are very subtle, thus difficult to find without the modern techniques. The paper presents some aspects of such an approach with the use of Scanning Electron Microscopy (SEM) to analyze internal defects that can critically decrease the performance of castings. The paper presents the so-called bifilm defects in ductile and chromium cast iron, near-surface corrosion caused by sulfur, micro-shrinkage located under the risers, lustrous carbon precipitates, and other microstructure features. The method used to find them, the results of their analysis, and the possible causes of the defects are presented. The conclusions prove the SEM is now a powerful tool not only for scientists but it is more and more often present in the R&D departments of the foundries.
Today, foundries are facing increasing demands for greener and more economical production while maintaining or improving the quality of the castings produced. The importance and use of green sand mixtures using bentonite as a binder are thus coming to the fore once again. They have the advantage of both eliminating the chemicalization of production and also allowing the immediate use of the already used mixture, including the binder, after adjustment of the composition and mulling. In order to maintain the quality of the resulting castings, it is necessary to monitor the properties of the moulding mixture through a series of laboratory tests. It is also essential to look at the processing quality of these mixtures, i.e. the combination of good mulling quality and efficient mulling time, which is often neglected. It is the quality of mulling and the effective mulling time that help to develop the bonding properties of the bentonite, improve the properties of the mixture, determine the efficiency of the muller and possibly reduce the time and energy required for mulling. The aim of this work is to present the effect of mulling on the properties of sand-water-bentonite mixtures. The properties studied are mainly the compactability, strength characteristics, moisture content of the mixture and the order of addition of raw materials.
This article discusses the possibility of using a two-track X-S control card on a Mesas device to control the production process parameters of piston castings for combustion engines. The research was carried out at the Federal-Mogul Gorzyce company. The basis for estimating the variability of the process results from the mean value (X) is the standard deviation (S). Thanks to specially designed measuring stations that use algorithms to calculate process indicators (Cp and/or Cpk) and their visualization, the cost of manufacturing products and the number of non-compliant products (scraps) are reduced. The process stability was investigated by measuring the key dimensions of the piston casting in a specific population and a given measurement cycle. Taking into account the precision of details, their technical condition, and surface quality, the production machines and cutting tools were optimally selected. It has been found that an important element of the effective use of Statistical Process Control (SPC) are trained/experienced operators who can correctly interpret the resulting control chart forms.
The use of cast aluminium has still increased, so have the mechanical property requirements. By casting and also in other metallurgical processes, the inclusions enter to the molten aluminium alloy and it exhibits poor ductility or toughness. It can cause a variety of problems in the manufacture of aluminium alloy castings. Therefore, the purification of the molten aluminium alloy is one of the most important processes for improving the quality of Al-products. Filters have been used for many years in order to improve the quality of castings. The inclusions in molten secondary AlSi7Mg0.3 cast were removed using depth filtration by ceramic foam filters of 20 ppi porosity. Were used 4 types of ceramic filters in 2 thicknesses (15 and 22 mm); Brinell hardness and porosity were measured. Quality of microstructure (occurrence of oxidic particles and larger non-metallic inclusions) was observed. Experimental results show that the insertion of ceramic filters into the inlet system has contributed primarily to a decrease in porosity. On the microstructure, the inclusion of filters was not significantly reflected.
The quality of aluminum casts is necessary in order to reach sufficient properties required for application. The decreasing in the properties of aluminum cast mainly related with microstructure, especially with size and morphology of second phases. One of such second phases in aluminum alloys are the β-phases. These phases are unwonted mainly because of the decreasing of mechanical properties. The contribution is deal with influence of addition of Mn to affecting the formation of βphases in the AlSi7Mg0.3 and AlSi7Mg0.6 cast alloys. These materials are used for application especially automotive industry. The results shows, that addition of Mn is not sufficient for affecting of formation of the Fe-rich phases in AlSi7Mg0.6 cat alloys, but in the AlSi7Mg0.3 this addition lead to changes in formation of Fe-rich intermetallic phases.
W pracy porównano sposób zasilania pojazdu paliwem CNG z paliwami konwencjonalnymi oraz paliwem LPG. Poruszono aspekty ekonomiczne i zasadnicze różnice w budowie instalacji CNG i LPG. Przedstawiono wymagania stawiane reduktorom CNG. Opisano ich budowę, parametry techniczne oraz warunki pracy. Zasygnalizowano rodzaje badań, określające jakość korpusów reduktorów, które są prowadzane przed wprowadzeniem produktu do seryjnej produkcji. Scharakteryzowano i opisano kryteria wyboru materiału odlewanego korpusu reduktora R14 STAG. W badaniach własnych przedstawiono wady odlewnicze korpusu reduktorów oraz zaproponowano zmiany w procesie kontroli korpusów, w celu zapobiegania instalacji nieszczelnych reduktorów CNG.
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The paper compared the method of supplying the vehicle with CNG fuel as compared to conventional fuels and LPG. Economic aspects and other fundamental differences in the construction of the CNG and LPG installations are discussed. Requirements for CNG reducers are presented. Their construction, technical parameters and working conditions have been described. The types of tests determining the quality of reduction gear housings, which are carried out before the product is put into series production, have been indicated. The criteria for selecting the cast material of the R14 STAG reducer body have been characterized and described. In our own research, casting defects of the reducer body were presented and changes in the body inspection process were proposed in order to prevent installation of leaking CNG reducers.
Conducting reliable and credible evaluation and statistical interpretation of empirical results related to the operation of production systems in foundries is for most managers complicated and labour-intensive. Additionally, in many cases, statistical evaluation is either ignored and considered a necessary evil, or is completely useless because of improper selection of methods and subsequent misinterpretation of the results. In this article, after discussing the key elements necessary for the proper selection of statistical methods, a wide spectrum of these methods has been presented, including regression analysis, uni- and multivariate correlation, one-way analysis of variance for factorial designs, and selected forecasting methods. Each statistical method has been illustrated with numerous examples related to the foundry practice.
The presented work is aimed to deal with the influence of changes in the value of negative (relative) pressure maintained in the die cavity of pressure die casting machine on the surface quality of pressure castings. The examinations were held by means of the modified Vertacast pressure die casting machine equipped with a vacuum system. Castings were produced for the parameters selected on the basis of previous experiments, i.e. for the plunger velocity in the second stage of injection at the level of 4 m/s, the pouring temperature of the alloy equal to 640°C, and the die temperature of 150°C. The examinations were carried on for three selected values of negative gauge pressure: - 0.03, - 0.05, and - 0.07 MPa. The quality of casting was evaluated by comparing the results of the surface roughness measurements performed for randomly selected castings. The surface roughness was measured by means of Hommel Tester T1000. After a series of measurements it was found that the smoothest surface is exhibited by castings produced at negative gauge pressure value of - 0.07 MPa.
The article presents an analysis of the applicability of the Replicast CS process as an alternative to the investment casting process, considered in terms of the dimensional accuracy of castings. Ceramic shell moulds were based on the Ekosil binder and a wide range of ceramic materials, such as crystalline quartz, fused silica, aluminosilicates and zirconium silicate. The linear dimensions were measured with a Zeiss UMC 550 machine that allowed reducing to minimum the measurement uncertainty.
W pracy badaniom poddano powłokę cynkową ukształtowaną na powierzchni odlewu z żeliwa sferoidalnego gatunku EN-GJS-500-7. Badania przeprowadzono pod względem oddziaływania ziaren eutektycznych i osnowy metalowej dla tego rodzaju żeliwa. W tym celu wykonano odlewy o grubości ścianki od 5 do 30 mm i oceniono powstałą strukturę. Aby uzyskać jednorodną osnowę metalową w próbkach badawczych przeprowadzono zabieg wyżarzania ferrytyzującego. Dla zwiększenia oddziaływania ciekłego cynku na powierzchnię odlewu usunięto jego warstwę wierzchnią metodą obróbki mechanicznej. Następnie przeprowadzono zabieg cynkowania zanurzeniowego w temperaturze 450°C w celu zbadania kinetyki wzrostu powłoki ochronnej (w założonym czasie metalizacji t od 60 do 600 sekund). Analizując wyniki badań stwierdzono, że w zakresie przyjętego czasu t procesu metalizacji różnice grubości ukształtowanej powłoki cynkowej dla próbek o zróżnicowanych wymiarach były niewielkie. Wynik taki świadczy o znikomym wpływie ziaren eutektycznych żeliwa (a tym samym wydzieleń grafitu sferoidalnego) na kinetykę wzrostu powłoki podczas metalizacji zanurzeniowej odlewu.
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Studies were conducted on a zinc coating produced by hot-dip galvanizing process on the surface of ductile iron grade EN-GJS-500-7 to determine the eutectic grain effect. For this purpose, castings with a wall thickness 5, 10, 20 and 30 mm were made and the resulting structure was examined. Due to the gain in each of the test samples various part ferrite and pearlite annealing treatment was carried out to obtain a homogeneous ferritic metal matrix. To enlarge the reaction surface, the top layer was removed from casting by machining. Then hot-dip galvanising treatment was performed at 450°C to capture the kinetics of growth of the zinc coating (in the period from 60 to 600 seconds). Analysing the test results, it was found that within the same time of hot dip galvanising, the differences in the resulting zinc coating thickness on samples taken from castings with different wall cross-sections were small but could, particularly for shorter times of treatment, reduce the continuity of the alloyed layer of the zinc coating.
W zakładach przetwórstwa metali wielokrotnie można spotkać się z zapytaniem klientów o możliwości produkcji jednostkowej wyrobów lub produkcji krótkiej serii. Jednym z rozwiązań tego typu problemu może być zastosowanie technik Rapid Prototyping do wytwarzania modeli odlewniczych. Analiza możliwości wykorzystania technik Rapid Prototyping do wykonania modeli odlewniczych w połączeniu z zastosowaniem odlewania precyzyjnego, a w szczególności najstarszej i najbardziej rozpowszechnionej metody wytapianych modeli, to zagadnienia, które podejmuje artykuł. Zakres badań dotyczył wykonania odlewów próbnych ze stopu cynku metodą wytapianych modeli z modeli wykonanych techniką Rapid Prototyping oraz ocenę jakości uzyskanego odlewu na podstawie badań chropowatości powierzchni.
EN
The metal-processing plant often meet costumers asking about the possibility of one piece production or manufacture of a short series. One of the solution is to apply rapid prototyping techniques to produce cast models. The aim of this paper is to present opportunity of implementation cast models produced with Rapid Prototyping in precision casting. Research concerns the implementation of test castings from zinc alloy melted by models with models made with Rapid Prototyping technique and the quality of the casting obtained on the basis of surface roughness.
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The goal of this study is to investigate the impact of equipment efficiency in casting machines on the quality of die castings made of Al-Si alloys in consideration of their modernity. Analysis focused on two cold-chamber die-casting machines. The assessment of modernity of the equipment was made based on ABC analysis of technology and Parker’s scale. Then, the coefficients of total productive maintenance (TPM) were employed for assessment of the efficiency of both machines. Using correlation coefficients r allowed authors to demonstrate the relationships between individual TPM coefficients and the number of non-conforming products. The finding of the study is pointing to the differences between the factors which determine the quality of castings resulting from the level of modernity of machines.
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W artykule przedstawiono porównanie jakości odlewów wykonanych metodą wytapianych modeli na bazie modeli z mieszanek otrzymanych głównie z recyklingu z odlewami wykonanymi w procesie Replicast CS. W ramach oceny jakości sprawdzono parametry mikrogeometrii powierzchni odlewów oraz dokładności wymiarowej. Dokładność wymiarowa obejmuje ponadto odchyłki wymiarowe w fazie wykonania modeli wytapianych, modeli z polistyrenu spienionego oraz form ceramicznych. Dokonano oceny jakości odlewów w aspekcie ekologii.
EN
In the article it was presented comparison of castings quality obtained during lost-wax process in case of recycled wax mixture and castings obtained during Replicast CS process. It was verified parameters of castings surface microgeometry and dimension accuracy. Moreover dimension accuracy contain dimension deviation appeared during wax and polystyrene models process and ceramic mould manufacturing. The quality of castings in case of ecology aspects was also verified.
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Przedstawiono wymagania stawiane wyrobom odlewanym oraz warunki zapewnienia ich jakości. Podkreślono istotną rolę klienta w formułowaniu wymagań. Zestawiono normy, których spełnienie jest warunkiem utrzymania systemu zarządzania jakością odlewów.
EN
The study discusses the conditions of quality assurance in the casting manufacturing process, standard terms and conditions of casting delivery, an identification system of casting delivery terms and conditions, the terms of easting acceptance, and means and tools of casting quality assurance.
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The aim of the present study has been designing and putting in operation of a stand for sonic testing equipped with modern and readily available numerical devices and with the author's own computer program, which enables recording and analysis of acoustic fields and of the frequency of free vibrations in selected castings made from Fe and Al alloys, and specifically also from magnesium alloys, and mastering the technique of making such tests along with their practical application in assessment of the quality of castings made from magnesium alloys and investment castings made from carbon steel.
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The article proves that the stepped pattern can be a versatile tool in examinations of casting quality, i.e. in determination of dimensional accuracy and surface microgeometry. Moreover, the pattern may be useful in evaluation of some important technological parameters used by investment casting technology, e.g. in evaluation of the anisotropy of the ceramic mould properties, which considerably affects errors of the dimensional deformation [...] at successive stages of the technological process of making ceramic moulds and investment castings. The results of the measurements of investment castings made in mixtures of the ceramic materials, like SiO2 and aluminosilicates – Molochite bonded with silicate binders, like colloidal silica, ethyl silicate, SIKOP [1], EKOSIL [2], were evaluated.
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Purpose: A methodology of the computer-aided determining relationship between chemical composition of aluminium alloy and castings quality was presented in the paper. Design/methodology/approach: To resolve the problem artificial neural networks were used. Classification problems were evaluated by the consideration mainly the values of mistakes and correct answers of networks for test data. On the basis of data analyzed by the neural network, which has the best quality classification of chemical composition of tested material, the concentration of alloying elements range, which have an effect on formation casting defects, were developed to eliminate them in the future. Findings: Combining of all methods making use of chemical composition of aluminium alloy and neural networks will make it possible to achieve a better casting quality. Research limitations/implications: The presented issues may be use, among others, for manufacturers of car subassemblies from light alloys, where meeting the stringent quality requirements ensures the demanded service life of the manufactured products. Originality/value: The correctly specified number of chemical composition of aluminium alloy enables such technological process control where the number of castings defects can be reduced by means of the proper correction of the process.
Omówiono podstawy fizyczne propagacji fal dźwiękowych w ośrodkach anizotropowych, jakimi są stopy techniczne stosowane na odlewy, w których występują wady (np. zróżnicowanie struktury, porowatości, pęknięcia itp.), traktowane jako przerwy w ciągłości. Wady te determinują częstotliwość drgań własnych odlewów, co pozwala na identyfikację odlewów nie spełniających ogólnych wymagań określonych przez warunki techniczne ich odbioru. Prowadzone badania wstępne, polegające na zbudowaniu eksperymentalnego stanowiska pomiarowego oraz na pomiarze częstotliwości drgań własnych kilku rodzajów odlewów, pozwalają stwierdzić, ze metoda ta może stanowić interesujący i tani sposób identyfikacji odlewów brakowych , który może znaleźć zastosowanie w praktyce produkcyjnej.
EN
Physical bases of the propagation of sonic waves in anisotropic media, which are technical alloys used for castings in which defects occur (e.g. diversification of structure, porosity, cracks etc.), regarded as discontinuities are discussed. These defects determine the free vibration tendency of castings, what allows to identify the castings not fulfilling the general technical acceptance conditions. The carried out initial tests which depended on building an experimental measurement stand and on the measurement of the free vibration tendency of some types of castings allow to state, that the method can be an interesting and cheap way of identification of rejected castings. This method can find application in the production practice.
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