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1

Application of the Triboelectric Method for the Ongoing Assessment of the Quality of Reclaim in Mechanical Reclaimers

Dańko R., Pietrzak A., Gruszka D.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 2

63--70

EN

The method of the ongoing assessment of the reclaim quality originating from the mechanical reclamation is described in this paper. In the process, the triboelectric system of measuring amounts of dust in the dedusting part of a reclamation device was applied. Based on the online measurements of the amounts of dust generated in the spent sand-reclamation process and the post-process determinations of the ignition losses and granular structures of the removed dust, the proper work parameters of the experimental reclaimer were selected. The allowable value of the ignition losses as well as the main fraction of the reclaimed matrix being similar to fresh sand was assumed as the main criteria of the positive assessment of the process. Within the presented investigations, a periodically operating device for rotor-mechanical reclamation was developed. The possibility of changing the intensity and time of the reclamation treatment as well as the triboelectric system of the dust-amount measuring were applied in this device. Tests were performed for the spent moulding sand with phenol-resol resin Carbophen 5692 hardened by CO2. This sand represents the moulding sand group with a less harmful influence on the surroundings for which the recovery of the quartz matrix utilising the reclamation requires stricter control of the parameters of the reclamation process and reclaim quality.

2

Primary Used Sand Reclamation Process Efficiency

Skrzyński M., Dańko R.

Archives of Foundry Engineering

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2019

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iss. 1

29--34

EN

The results of the efficiency of the primary reclamation process as well as the influence of the used sand temperature and other process parameters on it are presented in this paper. A separate stand realized on a reduced scale was built, which is an analogous process of the primary reclamation treatment of spent foundry sands. The used sands were introduced to the crushing process in an agglomerated form in the way typically used in industrial devices. The primary reclamation process was realized on a set of four horizontal sieves with decreasing mesh clearances while maintaining their geometrical dimensions applied in the Regmas industrial device. The model system consists of a vibratory drive mounted on the table, allowing us to control the supply frequency of the vibratory motors within a range of 40-60 Hz as well as the computer system for measuring the vibration parameters and drive power. The used sand on the quartz matrix with the KALTHARZ U404 resin and 100T3 hardener was used in our investigations. The used sand was prepared under the following conditions: cubic-shaped elements made of the applied furan sand was compacted by vibrations then hardened and subjected to heating under controlled conditions (as a “simulation” of the overheating process taking place in the mold after pouring). Time functions of the crushing and sieving process in dependence of the overheating degree of the reference sand samples (100°, 200°, and 300°C) were investigated at various table vibration frequencies and feed loads of the sieve set. The relative index of the crushing ability was determined.

3

Badania naukowe oraz ksztalcenie inżynierów-odlewników na Wydziale odlewnictwa akademii Górniczo-Hutniczej w Krakowie

Dańko R., Górny M., Szucki M.

Przegląd Odlewnictwa

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2018

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Vol. 68, nr 7-8

252--258

PL

Artykuł przedstawia strukturę organizacyjną, perspektywy badawcze w zakresie teorii procesów odlewniczych oraz działalność dydaktyczną Wydziału Odlewnictwa Akademii Górniczo-Hutniczej w Krakowie.

4

Studies of the Influence of the Number and Distribution of Vents on the Production Process of Cores by the Blowing Method

Dańko R.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

105--111

EN

The results of studies of the cores production by blowing methods with utilising the modified experimental shooting machine SR-3D, are provided in the hereby paper. The core sands from the Cordis technology were applied in the presented investigations. The influence of the number and distribution of vents on the shaped core box filling, filmed by a digital camera, was determined. Investigations were performed for the shooting pressures of 0.4, 0.5 and 0.6 MPa and for three surfaces of the shooting hole, at various numbers and distribution ways of vents in the experimental core box. The selected results of the model investigations were compared with the results of simulations performed previously in the PROCAST programme. The intensity of the core sand outflow from the shooting chamber into the core box of the experimental shooting machine was measured. Technological effects were assessed on the basis of the core sand apparent density in individual parts of the core, in dependence on the character of the pressure increase in the shooting chamber and the pressure value obtained in the core box.

5

Thermal Utilization of the Post Reclamation Dust from Molding Sand with Furan Resin in Test Unit

Holtzer M., Dańko R., Dańko J.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

15--18

EN

Mechanical reclamation process of spent moulding sands generate large amounts dusts containing mainly rubbed spent binding agents and quartz dust. The amounts of post-reclamation dusts, depending of the reclamation system efficiency and reclaim dedusting system, can reach 5-10% in relation to the total reclaimed moulding sand. This dust due to the high content of the organic substances is a threat to the environment and therefore requires the storage on landfills specially adapted for this type of waste. On the other hand, the presence of organic substances causes that these dusts have relatively high energy values that could be used. However, at present there is no coherent, environmentally friendly concept for the management of this type of dust. The paper presents the results of tests of thermal utilization the dusts (as a source of energy) were carried out at AGH University of Science and Technology. Thermal utilization of dusts was carried out in the co-burning with carbon carriers process or in individual burning (Patent PL 227878 B1 and patent application PL - 411 902).

6

Research on the Energy of Destruction of Bindings of a Core and Moulding Sand Based on Quartz Sand Grains

Dańko R., Dajczer G.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

19--22

EN

In the knock-out process, as well as in the preliminary phase of moulding sand reclamation, the issue of energy demand for the process of crushing used sand agglutinations, preferably to single grains, is particularly important. At present, numerical values of moulding sand impact resistance, which would allow energy-related aspects of this process to be forecast, are not known, as such research has not been carried out. It seems that impact resistance tested on very small cross-section samples, which allows us to very precisely reveal some unique features of a moulding sand with organic and inorganic binders, is an important parameter, which so far has not been taken into account for evaluation of mechanical properties of moulding sands. Preliminary attempts to determine impact resistance of moulding sands have been carried out as part of own research of the author. The conducted investigations aimed at determining the relationships between the obtained values of tensile strength and impact resistance of moulding sands. In addition, the effect of holding samples at temperatures of 100oC, 200oC, 300oC on the value of impact resistance was determined, both for sands made with fresh and with reclaimed sand grains.

7

Investigations of the Mechanism of the Sand Shooting into the Core Box

Dańko R.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 3

113--119

EN

The results of investigations of sand shooting into the core box are presented in the hereby paper. The investigations concern the formation of the diphase sand-air flux, its motion, flowing and compaction in the cavity during the core forming. Conditions deciding on the course of individual phases of the process are discussed with taking into consideration the influence of such factors as: the shot pressure, shooting hole diameter, number and distribution of deaerating vents in experimental core boxes (of a single cavity and of multi cavities) on the core sand compaction state. Investigations were performed by means of the modernised experimental shooting machine SR-3D, of the shooting chamber volume of 3.3 dm3, connected with the system of pneumatic supply ensuring the stable pressure supply of values: 0.4 MPa, 0.5 MPa and 0.6 MPa. Two diameters of the shooting hole, equal 10 mm and 20 mm, were applied for filling three experimental core boxes differing in dimensions of cavities and in number and distribution of deaerating vents. The filling process of core boxes was recorded by means of the digital camera PHANTOM V210 with the filming rate of 3000 pictures in second. Simultaneously, during the shot, other values allowing to determine the intensity of the core sand outflow from the shooting chamber to the core box, were tested. The presented in this publication results constitute the important element of the experimental verification of the blowing process simulation calculations which will be performed.

8

Compaction of Cores Made by Blowing Methods – Model Investigations

Dańko R.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

191--197

EN

The results of model investigations of the influence of the blowing process selected parameters on the distribution of the compaction of the core made by the blowing method, are presented in the hereby paper. These parameters were: shooting pressure, shooting hole diameter, amount and distribution of deaerating holes. Investigations were performed using the horizontal core box of the cuboidal cavity and the same core box into which inner inserts were introduced. These inserts were dividing the primary volume into three sectors differing in their direction, introduction conditions and the character of the core sand flow. As the compaction measure the apparent sand density was assumed. The density was determined in five measuring points in case of uniform cores, and in three measuring points in case of cores obtained in the core box with three separated sectors. The apparent density of the compacted core sand in the core box cavity was determined on the basis of the measurements of masses and volumes of samples cut-out from the determined core places by means of the measuring probe. Investigations were performed at three values of the working pressure equal 0.4, 0.5 and 0.6MPa for two diameters of the shooting hole: 10 and 20 mm. During tests the core box deaeration, controlled by an activisation of the determined number of deaerating vents placed in the core box, was also subjected to changes.

9

Modelling of the material destruction of vertically arranged honeycomb cellular structure

Piekło J., Małysza M., Dańko R.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1300--1308

EN

The paper presents the results of the experimental and numerical analysis of material destruction of honeycomb cellular structure. Based on the experimental research, the results of numerical calculations regarding the compression process were verified along with the correctness of used constitutive numerical model. The destruction was analyzed for the casting with no structural defects and for the casting with detected porosities. The results were compared to the structural strength of the honeycomb structure manufactured on the CNC machine. The metallic honeycomb structure was manufactured as a casting of Al alloy in the investment casting technology. For manufacturing purposes the honeycomb model was obtained in additive manufacturing process. The castings and the CNC honeycomb were used in the compression test trials. The process was controlled by the displacement and the results were registered as the changes of the height and the force value. Based on the experimental results the numerical model of honeycombs was introduced for the numerical analysis of the energy absorption and compression process. The results showed good correlation between the experiment and FEM (Finite Element Method) analysis.

10

Rola dokładności i powtarzalności ilościowej dozowania ciekłego stopu w zimnokomorowym procesie odlewania pod wysokim ciśnieniem

Kowalczyk W., Dańko R.

Przegląd Odlewnictwa

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2017

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Vol. 67, nr 1-2

22--25

PL

W publikacji omówiono rolę dokładności i powtarzalności ilościowej dozowania ciekłego stopu w procesie wytwarzania odlewów ciśnieniowych w maszynach zimnokomorowych. Szczególną uwagę zwrócono na wahania teoretycznego punktu przełączenia drogi tłoka prasującego z I na II fazę, wywołane brakiem powtarzalności ilościowej dozowania ciekłego stopu oraz na technologiczne i ekonomiczne konsekwencje zaburzenia stabilności procesu produkcyjnego.

EN

The function of the accuracy and quantitative reproducibility of liquid alloy feeding in the die casting production process in cold-chamber machines, was elaborated in the hereby paper. A special attention was directed towards fluctuations of the theoretical point of switching the pressing piston from phase I into phase II, caused by the lack of the quantitative reproducibility of liquid alloy feeding. The economical and technological consequences of the production process disturbances, were also considered.

11

Density Distribution and Resin Migration Investigations in Samples of Sand Core Made by Blowing Method

Dańko R., Jamrozowicz Ł.

Journal of Casting & Materials Engineering

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2017

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Vol. 1, no. 3

70--73

EN

Resin migration in a core can occur during the core production process performed by blowing methods in which the core sand is transported into the core box as a two-phase sand-air flux characterized by various working parameters (working pressure, shooting time, volumetric concentration). This migration is the result of the resin being blown off from the matrix grain surfaces by compressed air. The methodology of the investigation of this effect developed at AGH University of Science and Technology is presented in this paper. The results of the resin migration tests obtained for cores made with cold-box technology at various working parameters of the shooting process are also shown.

12

Application of Computer Support for Design of Shaft Furnaces – Cupolas

Dajczer G., Dańko R.

Journal of Casting & Materials Engineering

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2017

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Vol. 1, no. 4

85--89

EN

Designing a machine’s constructions and an object’s structures is one of the areas of technology design. The complexity of the structure is defined by the technology for which it is used. Following the theory of construction and mechanisms, the full characteristics of a machine or device is defined by its shape and operating parameters. The shape reflects geometry. As a result of using the correct parameters, the construction should functional correctly (which means according to its general principles of operation). The project of any structure is a creative process performed by a team of designers and constructors. The contemporary design is not solely based on the personal preferences of engineers. More and more scientific and computerized design methods are being introduced to this process. They are characterized as computer-aided systems and are based on algorithms, programs, and IT equipment. This article presents the methodological application of computer-aided design on an example of the design of shaft furnaces that are used in foundries as cast iron smelters. These furnaces, called cupolas, have again become objects of interest for research. In the design of the cupola construction, Autodesk Inventor techniques were used.

13

Validation of the Theoretical Model of Determining the Strength of Cores Made by the Blowing Method

Dańko R.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 3

27--30

EN

Core sands for blowing processes, belong to these sands in which small amount of the applied binding material has the ability of covering the sand matrix surface in a way which - at relatively small coating thickness - allows to achieve the high strength. Although the deciding factor constitute, in this aspect, strength properties of a binder, its viscosity and ability to moisten the matrix surface, the essential meaning for the strength properties of the prepared moulding sand and the mould has the packing method of differing in sizes sand grains with the coating of the binding material deposited on their surfaces. The knowledge of the influence of the compaction degree of grains forming the core on the total contact surface area can be the essential information concerning the core strength. Forecasting the strength properties of core sands, at known properties of the applied chemically hardened binder and the quartz matrix, requires certain modifications of the existing theoretical models. They should be made more realistic with regard to assumptions concerning grain sizes composition of quartz sands and the packing structure deciding on the active surface area of the contacts between grains of various sizes and - in consequence - on the final strength of cores.

14

Influence of the Matrix Grain Size on the Apparent Density and Bending Strength of Sand Cores

Dańko R.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

27--30

EN

The results of investigations of the influence of the matrix grain sizes on properties of cores made by the blowing method are presented in the hereby paper. Five kinds of matrices, differing in grain size compositions, determined by the laser diffraction method in the Analysette 22NanoTec device, were applied in investigations. Individual kinds of matrices were used for making core sands in the Cordis technology. From these sands the shaped elements, for determining the apparent density of compacted sands and their bending strength, were made by the blowing method. The shaped elements (cores) were made at shooting pressures being 3, 4 and 5 atn. The bending strength of samples were determined directly after their preparation and after the storing time of 1 hour.

15

Assessment of the Possibility of Using Reclaimed Materials for Making Cores by the Blowing Method

Dańko R., Dańko J., Skrzyński M.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

21--26

EN

The cumulative results of investigations of the possibility of using the reclaimed materials after the mechanical, thermal or mechanical-thermal reclamation for making cores by means of the blowing method in the alkaline CO2 technology, are presented in the paper. Three kinds of spent sands: with furfuryl resin, bentonite and alkaline phenolic resin, obtained from the foundry, were subjected to three kinds of reclamation: mechanical, thermal and combined mechanical-thermal, applying for this aim adequate experimental devices. The obtained reclaims were assessed with regard to the degree of the matrix liberation from the determined binding material. Reclaims of moulding sands with binders of the form of resin were assessed with regard to ignition loss values and pH reaction, while reclaims of moulding sands with bentonite with regard to the residual clay content and pH value. In all cases the results of the performed sieve analyses were estimated and the average characteristic diameter dl was determined. The reclaimed matrix was applied as a full substitute of the fresh high-silica sand in typical procedures of preparing core sands used for making shaped samples for bending strength investigations, Rgu.

16

Investigation of the Results of Combined Reclamation on the Particular Stages of Grain Matrix Recovery

Łucarz M., Dańko R., Dereń M., Skrzyński M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

2151--2158

EN

In this article, there were presented the results of research on combined mechanical and thermal regeneration of waste moulding sand with furfuryl resin originated from one of national foundries manufacturing aluminium alloys castings. Attempts of mechanical reclamation were led on the REGMAS reclaimer enabling to realize preliminary and primary reclamation with use of two modes of mechanical interactions on waste moulding sand. In the first attempt the reclaimer worked without any additional regenerating elements, and as the second solution, the reclaimer operated with additional crushing and abrasive elements to increase the result of primary reclamation. Thermal reclamation was led in the prototypic thermal reclaimer, enabling to fully control the process of grain matrix recovery. As a result of completed investigations the small efficiency of mechanical reclamation was determined. However, use of combined regeneration allowed for obtaining grain matrix of high purity. Thermal regeneration was conducted in prototypic thermal reclaimer. Evaluation of reclaim (reclaimed material) quality was carried out in the way of iginition losses and grain-size analysis, surface morphology and also by executing of strength testing of moulding sand prepared on obtained grain matrix for the particular reclamation operations.

17

Assessment of the Harmfulness of Moulding Sands with Alkyd Resin Subjected to the High Temperature Influence

Holtzer M., Dańko R., Żymankowska-Kumon S., Kubecki M., Bobrowski A.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

2171--2176

EN

Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. These resins in their initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin, under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene), and also polycyclic aromatic hydrocarbons (PAHs) can be formed and released. The aim of the study was the development of the method, selection of analytical methods and the determination of optimal conditions of formation compounds from the BTEX and PAHs group. Investigations were carried out in the specially designed set up for the thermal decomposition of organic substances in a temperature range: 500 – 1 300°C at the laboratory scale. The object for testing was alkyd resin applied as a binding material for moulding sands. The qualitative and quantitative analyses of compounds were performed by means of the gas chromatography coupled with the mass spectrometry (GC/MS).

18

Influence of the Reclamation Process Intensity in the REGMAS Reclaimer on the Purification Degree of the High-silica Matrix

Skrzyński M., Dańko R.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 1

69--72

EN

The investigation results of the reclamation of spent moulding sands with furfuryl resin are presented in this paper. The reclamation process was performed in the secondary reclamation chamber of the REGMAS 1.5 vibratory reclaimer. 70 kg portions of moulding sands, previously subjected to the primary reclamation and dedusting, were used. The secondary reclamation was performed in two stages: the first consisted of determining the reclaimer intensity at various reclamation times (5 min, 10 min and 15 min) and various electrovibrator frequencies (40 Hz, 50 Hz and 60 Hz), the second consisted of determining the influence of additional crushing elements on the intensity of processes.

19

Influence of the Hardener on the Emission of Harmful Substances from Moulding Sands with Furan Resin in the Pyrolysis Process

Holtzer M., Kmita A., Żymankowska-Kumon S., Bobrowski A., Dańko R.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 1

107--111

EN

The furan resin offers advantages such as high intensity, low viscosity, good humidity resistance and is suitable for cast different casting alloys: steel, cast iron and non-ferrous metal casting. For hardening furan resins are used different hardeners (acid catalysts). The acid catalysts have significant effects on the properties of the cured binder (e,g. binding strength and thermal stability) [1 - 3]. Investigations of the gases emission in the test foundry plant were performed according to the original method developed in the Faculty of Foundry Engineering, AGH UST. The analysis is carried out by the gas chromatography method with the application of the flame-ionising detector (FID) (TRACE GC Ultra THERMO SCIENTIFIC).

20

Determination of the Surface and Volume Porosity, on the Basis of the Main Fraction of the Polifractional Matrix of Moulding and Core Sands

Dańko R., Dańko J.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

191--195

EN

The aim of the hereby paper is to present the developed model of determining the volume and surface porosity based on the main fraction of polifractional materials, its experimental verification and utilisation for the interpretation of effects accompanying the formation of a moulding sand apparent density, porosity and permeability in the blowing processes of the core and moulds technology.