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1

The influence of calcium carbonate and its modifications on the extrusion process and selected properties of polypropylene cast films

Kloziński Arkadiusz, Szczepańska Małgorzata, Jakubowska Paulina, Samujło Bronisław, Barczewski Mateusz, Lota Grzegorz

Polimery

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2022

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Vol. 67, nr 10

509--521

EN

The effect of unmodified and stearic acid-modified calcium carbonate (5, 10, 20 and 30 wt%) on selected properties (tensile strength, puncture resistance, haze and gloss) and processability of polypropylene films (MVR, extensional viscosity) was investigated. The composites were obtained in the twin-screw extrusion process with cold granulation, and the films in the single-screw extrusion process, using a flat die head (so-called cast films) and a chill roll type cooling and pull-back device. It has been shown that stearic acid is an effective modifier of polypropylene processing properties both under shear and tensile flow conditions (lower extensional viscosity of films containing modified calcium carbonate).

PL

Zbadano wpływ dodatku 5, 10, 20 oraz 30 % mas. niemodyfikowanego imodyfikowanego kwasem stearynowym węglanu wapnia na wybrane właściwości użytkowe (wytrzymałość na rozciąganie, odporność na przebicie, zamglenie, połysk) iprzetwórcze folii polipropylenowych (MVR, lepkość wzdłużna). Kompozyty otrzymano w procesie dwuślimakowego wytłaczania z granulacją na zimno, a folie w procesie jednoślimakowego wytłaczania, przy użyciu głowicy płaskiej (tzw. cast films) oraz urządzenia chłodząco - odciągającego typu chill roll. Wykazano, że kwas stearynowy jest efektywnym modyfikatorem właściwości przetwórczych folii polipropylenowych zarówno w warunkach przepływu ścinającego, jak i rozciągającego (mniejsza lepkość wzdłużna folii zawierających modyfikowany węglan wapnia).

2

Forming of a bimetallic element for the resistance element soldering method

Schrek Alexander, Vanko Branislav, Sejč Pavol

Journal of Metallic Materials

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2022

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Vol. 74, no. 2

8--20

EN

The joining of sheet metal parts produced in the material combination of Fe-Fe, Fe-Al as well as Fe-thermoplastic and Al-thermoplastic can be realized by the Resistance Element Soldering (RES). Extruded bimetallic elements were used to form the overlap joint. The semi-finished product for extrusions was a Cu 99.9 tube with dimensions φ6 × 0.5 mm and length 9 mm, filled with Sn60Pb40 solder. “T” shaped overprints were produced in two ways. Simulation in the ANSYS software environment was chosen to optimize, select the appropriate forming process, and design the geometry of the functional parts of the forming tool, allowing to use only one extrusion forming operation. The results of the simulations are the magnitudes of stresses and strains, and different head shape geometries of the bimetallic element extrusions of the three proposed forming methods. The task was to achieve extrusions without defects of the Cu tube shell, such as corrugations and wrinkles. The geometry was observed and compared by macroanalysis of extrusion sections made on a laboratory forming tool.

PL

Łączenie części metalowych wykonanych z połączenia materiałów Fe-Fe, Fe-Al oraz termoplastycznych Fe i Al można wykonać metodą lutowania oporowego (RES - Resistance Element Soldering). Do wykonania połączenia zakładkowego użyto wytłaczanych elementów bimetalicznych. Półfabrykatem do wytłaczania była rura Cu 99,9 o wymiarach φ6 × 0,5 mm i długości 9 mm, wypełniona lutem Sn60Pb40. Nakładki w kształcie litery „T” wykonywano na dwa sposoby. W celu optymalizacji, doboru odpowiedniego procesu formowania i zaprojektowania geometrii funkcjonalnych części narzędzia kształtującego wybrano symulację w środowisku oprogramowania ANSYS, co pozwala na użycie tylko jednej operacji kształtowania przez wytłaczanie. Wynikiem symulacji są wielkości naprężeń i odkształceń oraz różne parametry geometryczne kształtu głowic wytłoczonych elementów bimetalicznych z trzech proponowanych metod kształtowania. Celem było uzyskanie wytłoczek pozbawionych wad powłoki rury z Cu, takich jak pofałdowania i zmarszczki. Parametry geometryczne obserwowano i porównywano za pomocą makroanalizy produktów wytłaczania wykonanych w laboratoryjnym narzędziu kształtującym.

3

Analyzing mechanical behavior of ABS-SiO2 polymer-based nanocomposite based on ANOVA method

Afzali Mohammad, Asghari Vahid

Composites Theory and Practice

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2021

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R. 21, nr 3

61--69

EN

The fabrication of polymer-based nanocomposites by means of twin extruders is a typical method for manufacturing lightweight and high-strength structures. However, selection of the optimal parameters for this process to study the material characteristics is important. The primary aim of the present study was to ascertain the optimum extruder temperature and nanosilica content in an acrylonitrile-butadiene-styrene matrix composite. The response surface methodology was based on two factors and three levels. The identification of the effect of the parameters on the fatigue behavior of the fabricated composite was comprehensively analyzed. The results were analyzed using scanning electron microscopy (SEM). The obtained results revealed that up to 4% nano-SiO2 improves tensile strength and reduces the impact toughness. On the other hand, an increase in the extrusion temperature yields a higher impact toughness and lower tensile strength. The optimization results showed that 2.5% nanosilica and the extrusion temperature of 225°C result in the maximum tensile strength of 41 MPa, and impact toughness of 30 KJ/m2.

4

The extraordinary effect of very low content of hybrid carbonaceous reinforcement on the microstructural and mechanical properties of 7075 aluminum alloy

Ezatpour H. R., Torabi Parizi M., Ebrahimi G. R.

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

263--286

EN

Until recently, the strengthening efficiency of carbonaceous reinforcements in aluminum-based matrix nanocomposites (AlMNCs) was lower than expected. The intrinsic characteristics of matrix and carbonaceous reinforcements and fabrication technique, which affected the microstructural characterization, played main roles in determining the performance of Cs/AlMNCs. In this study a novel strategy was developed via flake powder metallurgy followed by slurry blending combined with rheocasting and hot-extrusion processing to prepare hybrid AA7075-matrix composite reinforced with CNTs + GNPs. No Al4C3 phase was detected in Raman spectrums, while uniform dispersion of carbonaceous hybrid reinforcements with minimal structural damage was observed. There were ~ 9% and 39% decrease in the average grain size of the as-casted and extruded CNTs + GNPs/AA7075 composites, respectively, compared to AA7075 alloy. In the extruded CNTs + GNPs/AA7075 composite, plate precipitates were predominant and some lath-like dynamic precipitates were observed at the GNPs/AA7075 interfaces. The micro-hardness, tensile yield strength (TYS), ultimate tensile strength (UTS) and uniform elongation (UE) of the CNTs + GNPs/AA7075 composite were improved by ~ 17%, 51%, 7% and 20% compared to AA7075 alloy. An ultra-high yield strengthening efficiency of carbonaceous hybrid reinforcements in AA7075 alloy up to 3950 was obtained, where load bearing was the main strengthening mechanism and carbonaceous reinforcements illustrated bridging and pulling-out in the fracture surfaces of composite.

5

The decisive impact of microstructure on the machinability of pure copper

Sun Xiaoxiang, Ebrahimi Mahmoud, Attarilar Shokouh

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

852--860

EN

Ultrafine-grained (UFG) materials have been of great attention due to their considerable behavior compared to coarse-grained counterparts. Also, the machinability of these UFG materials is of great importance because of the machining significance in manufacturing the final shape of industrial components. Hence, this study dealt with machinability in relation to the microstructure and mechanical properties of the UFG pure copper processed by the twist extrusion. The remarkable microstructure evolution through the dynamic recrystallization mechanisms improved the tensile strengths and hardness of the twist extrusion processed pure copper. Also, the reduction of ductility in the UFG copper compared to the initial state was related to the change of tensile fractography mechanism in which the large and deep dimples transformed into the combined small and shallow dimples with some cleavage planes in the UFG copper. Furthermore, the enhanced machinability of the processed sample was related to its lower thermal conductivity and the development of strain localization within the narrow shear bands which lead to the production of discontinuous short chips. Hence, the formation of the UFG structure is a suitable option to attain the enhanced machinability behavior of copper as one of the most used metals.

6

Effects of processing temperature and number of passes on the microstructure and mechanical properties of AA 6063 processed by cyclic expansion extrusion

Babu V., Shanmugavel Balasivanandha Prabu, Padmanabhan K. A.

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

632--648

EN

The effects of the working temperatures (260 °C, 200 °C and 130 °C) on microstructure formation in the AA 6063 alloy, processed upto ten passes by cyclic expansion extrusion (CEE) was studied. The microstructures of the CEE-processed specimens in the convergent and extrusion regions (center and edge) were examined after every two passes. The EBSD analysis revealed a decrease in the average grain size from 22 ± 5 µm to 2 ± 0.5 µm after four passes, with a simultaneous presence of a large fraction of HAGBs (45%) at 130 °C processing temperature. The TEM observations also confirmed the presence of nano-grains of sizes in the range of 50–100 nm. The CEE-processed specimen showed the highest improvement in hardness and ultimate tensile strength from 38 ± 3.4 HV and 118 ± 6 MPa to 122 ± 1 HV and 267 ± 2 MPa, respectively, after four passes at 130 °C. The specimens processed at 260 °C (ten passes), and 200 °C (four passes) showed moderate improvement in strength of 184 ± 3 MPa and 216 ± 3 MPa, respectively. On further straining (at 200 °C and 130 °C after six to ten passes), continuous dynamic recovery and dynamic re-crystallization took place which led to grain growth during SPD and, as a result, the alloy lost its strain hardening capacity and there was a decrease in the mechanical properties. At higher number of passes, the grains were elongated and coarsened, i.e., a non-equiaxed microstructure was seen after ten passes at 200 °C and 130 °C. In contrast, the specimen processed at 260 °C after ten passes, showed a homogeneous microstructure with near-equiaxed grains with 38% of HAGBs. A lower processing temperature produced a microstructure with a fine grain size distribution after a lower number of passes.

7

Estimation of Tribological Properties of Selected Plastics Materials Manufactured by Extrusion and 3D Printing

Bąkowski Henryk, Krzysiak Zbigniew

Tribologia

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2020

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nr 6

7--12

EN

The following work presents the results of research about the assessment of tribological properties of plastics used as components in modes of transport. For this purpose, the wear resistance of materials used in 3D printing (PA6CF and ABS), and extrusion moulding (PA) were tested. The tribological research was carried out with the use of the T-05 tester in the roller-block system. The samples in the form of cuboids with a concave rounding of one wall were made on a 3D printer using the FDM method. The counter-sample was a ring made of aluminium alloy subjected to anodizing. The research was carried out under a variable loads, in reciprocating motion, under dry friction conditions. After that the tribological characteristics were assessed. The research and analysis of the results confirmed the possibility of using selected plastics in modes of transport.

PL

W poniższej pracy przedstawiono wyniki badań polegających na ocenie właściwości użytkowych tworzyw sztucznych, które mogą być wykorzystywane jako podzespoły w środkach transportu drogowego. W tym celu przebadano odporność na zużycie materiałów wykorzystywanych w druku 3D – PAGF i ABS. Zakres prze prowadzonych badań obejmował badania tribologiczne oraz badania makroskopowe. Badania tribologiczne zostały przeprowadzone przy użyciu testera T-05 w układzie rolka–klocek. Próbki w formie prostopadłościanów z wklęsłym zaokrągleniem jednej ścianki zostały wykonane na drukarce 3D przy zastosowaniu metody FDM oraz metodą ekstruzji. Przeciwpróbkę stanowił pierścień wykonany ze stopu aluminium. Badania prze prowadzono pod obciążeniem 100, 300 i 500 N, w ruchu posuwisto-zwrotnym w warunkach tarcia suchego. Na ich podstawie dokonano oceny charakterystyk tribologicznych. Wykonane badanie i analiza ich wyników potwierdziły możliwość wykorzystania wybranych tworzyw sztucznych w środkach transportu drogowego.

8

Processing and structure of HDPE/glassy carbon composite suitable for 3D printing

Olesik Piotr, Kozioł Mateusz, Jała Jakub

Composites Theory and Practice

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2020

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R. 20, nr 2

72--77

EN

The following paper discusses the studies of high-density polyethylene (HDPE) reinforced with glassy carbon (GC) particles. The conducted research focused on the processing properties of the material. Samples were made from extruded HDPE filament reinforced with GC. The granulate for extrusion was made by depositing GC particles on the surface of HDPE granules in ethylene alcohol. The granulate was subsequently extruded in the form of a filament (1.6 mm in diameter). The filament was cut into smaller pieces, which were then prepared and examined using a light microscope. Density measurements and quantitative analysis were performed to examine the amount of glassy carbon in the samples. The measurements showed about a 1% volume of glassy carbon in the reinforced filament. The melt flow index was measured for the HDPE filament and HDPE filament reinforced with GC. The viscosity curves for the neat HDPE and the composite filament were determined. The reinforced HDPE filament was characterized by slightly lower flow parameters; however, the difference between the results was insignificant for material processing. The maximum feed rate of the prepared filament for the FDM 3D printing process was evaluated by mathematical modeling. The results show that both the prepared materials have a similar printing capability as commonly used PLA, only the composite filament should have a 1.4% lower feed rate than the neat HDPE.

PL

Przedstawiona praca dotyczy wstępnych badań nad polietylenem wysokiej gęstości (HDPE) zbrojonym cząstkami węgla szklistego (GC). Przeprowadzone badania skupiały się wokół struktury oraz właściwości przetwórczych uzyskanego kompozytu. Próbki zostały wytworzone z wytłoczonego filamentu HDPE zawierającego węgiel szklisty. Granulat do wytłaczania został przygotowany poprzez osadzanie cząstek GC na powierzchni granul HDPE w alkoholu etylowym, a następnie po wysuszeniu wytłoczony w postaci filamentu o średnicy ok. 1,6 mm. Przygotowany filament został poddany regranulacji, a następnie poddany obserwacji na mikroskopie świetlnym. Za pomocą pomiarów gęstości oraz analizy obrazu zdjęć z mikroskopu oceniono udział węgla szklistego w osnowie HDPE. Pomiary wykazała udział objętościowy zbrojenia na poziomie 1%. Właściwości przetwórcze zostały ocenione poprzez pomiary MFI oraz wyznaczonych na ich podstawie krzywych lepkości. Kompozytowy filament wykazywał nieznacznie mniejsze płynięcie w porównaniu do bazowego tworzywa. Ostatecznie oceniono maksymalny feed rate w procesie drukowania 3D (FDM) za pomocą modeli analitycznych dla wytworzonych filamentów. Wyniki modelowania pokazują, że oba przygotowane materiały mógłby być drukowane przy podobnych prędkościach jak popularne PLA.

9

Badania diagnostyczne przyczyn awarii wytłaczarki przemysłowej do tworzyw sztucznych ø90

Ładecki Bogusław

Badania Nieniszczące i Diagnostyka

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2020

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nr 1-4

38--41

EN

The paper discusses the case of premature failure of an industrial twinscrew extruder for plastics made of chromium-molybdenum stainless steel grade 1.4122 (3H17M). The diagnostic tests carried out, which included the performance of: non-destructive, metallographic, thermovision and hardness tests, gave the basis to indicate the causes of extruder damage associated with the entry of impurities in the input material.

PL

W referacie omówiono przypadek przedwczesnego uszkodzenia wytłaczarki przemysłowej dwuślimakowej do tworzyw sztucznych wykonanej ze stali nierdzewnej chromowo-molibdenowej gatunku 1.4122 (3H17M). Przeprowadzone badania diagnostyczne, w których skład wchodziło wykonanie: badań nieniszczących, metalograficznych, termowizyjnych i pomiarów twardości, dały podstawę do wskazania przyczyn wystąpienia uszkodzeń wytłaczarki, związanych z przedostawaniem się zanieczyszczeń w materiale wsadowym.

10

Superplastic deformation of Mg–9Li–2Al–0.5Sc alloy after grain refinement by KoBo extrusion and cyclic forging

Dutkiewicz Jan, Kalita Damian, Maziarz Wojciech, Faryna Marek

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 4

343--353

EN

The quaternary Mg–9Li–2Al–0.5Sc alloy (in wt%) was prepared from pure components. After homogenization, the alloy was subjected to severe plastic deformation by KoBo extrusion and cyclic forging leading to grain refinement in the range of 0.5–2 µm of hexagonal close-packed (HCP) α phase. Deformed alloys showed high ultimate tensile strength near 200 MPa and good elongation in the range 30–40% at room temperature (RT). Large elongations close to 200% were obtained during the tensile test at a temperature of 200 °C. Deformed samples showed the presence of multiple voids confirming grain boundary sliding mechanism of deformation. Twins on {101-2} planes were identified using electron backscatter diffraction analysis, being in a good agreement with the earlier observation of Mg–Li and Mg–Sc alloys. Intermetallic phases such as cubic MgSc were identified in deformed alloys mostly within HCP α phase, whereas HCP MgSc2 particles were observed within body-centered cubic (BCC) β phase. Intermetallic phases were responsible for RT strengthening of alloys and slightly lower tensile elongation during superplastic deformation. Formation of the HCP α phase was observed within the BCC β phase in tensile deformed alloys. Atomic-level nucleation of HCP phase within the β phase was identified by the use of high-resolution transmission electron microscopy technique.

11

Numerical Analysis of a Six Stage Forging Process for Producing Hollow Flanged Parts from Tubular Blanks

Winiarski Grzegorz, Bulzak Tomasz Adam, Wójcik Łukasz, Szala Mirosław

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 1

201--208

EN

This paper presents the results of a numerical analysis of a cold forging process for a hollow flanged part. The analysis was performed using Deform 2D/3D. 42CrMo4 steel tubes were used as the billet material, and their material model in the annealed state was described by a constitutive equation. The forming process was performed in six stages with the use of methods such as extrusion with a movable sleeve, open-die extrusion, and upsetting. The objective of the study was to determine whether the proposed forging technique could be used to produce hollow parts with flanges. The determination was made based on the analysis of product geometry quality and process parameters, including the Cockcroft-Latham ductile fracture criterion and forming forces.

12

A New Method of Flanges Extrusion in Hollow Products – Analysis of the Limiting Phenomena

Winiarski Grzegorz, Bulzak Tomasz Adam, Wójcik Łukasz, Szala Mirosław

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 4

78--85

EN

The paper presents an innovative method of metal forming of hollow flanged elements. In this process, flanges are formed using a movable sleeve, which moves in the opposite direction to the punch. The movement of the sleeve causes a closed impression to open, due to which the flange is also formed in a semi-free impression. The tube billets were made of the 42CrMo4 grade steel deformed under the cold metal forming conditions. The calculations were conducted using the finite elements method in Deform-2D/3D. Various technological parameters of the process were analysed, among others the diameter of the flange and the initial height of the impression of the movable sleeve. On the basis of the obtained results, the limiting phenomena of the process were determined and the influence of the analysed technological parameters on these phenomena were presented.

13

Studium wytłaczania polietylenu z dodatkiem nanorurek haloizytowych. Cz. 1, Charakterystyka procesu wytłaczania

Głogowska Karolina, Majewski Łukasz

Przemysł Chemiczny

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2019

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T. 98, nr 8

1313--1315

PL

Polietylen o małej gęstości napełniono haloizytowymi nanorururkami (średnica 30–70 nm, długość 1–3 μm) o udziale masowym 2–6% w stosunku do osnowy oraz bez dodatków, proces wytłaczania przeprowadzono w laboratoryjnej wytłaczarce jednoślimakowej przy prędkościach obrotowych ślimaka 50 rpm i 150 rpm. Zbadano wpływ składnika chemicznego i prędkości obrotowej ślimaka na parametry wytłaczania. Największą wydajność procesu (ponad 39,6%) osiągnięto podczas wytłaczania polimeru nienapełnionego przy prędkości ślimaka 150 rpm. Wydajność nieznacznie spadała (do 39,1%) wraz ze wzrostem zawartości nanorurek. Najmniejszą wartość jednostkowego zużycia energii osiągnięto przy wytłaczaniu (150 rpm) materiału zawierającego 2% haloizytu. Zastosowanie prędkości obrotowej ślimaka 50 rpm spowodowało znaczne zmniejszenie wydajności wytłaczania oraz znaczny wzrost jednostkowego zużycia energii dla badanych materiałów.

EN

Low d. polyethylene doped with halloysite nanotubes (diam. 30–70 nm, length 1–3 μm) in concns. 2–6% by mass as well as without additives was extruded in a single-screw lab. extruder at 50 rpm or 150 rpm. The effect of chem. compn. of obtained materials and rotational speed of the screw on the parameters of the extrusion process was tested. The highest efficiency of the process (over 39.6%) was achieved during extrusion at screw speed of 150 rpm of non-doped polymer. The efficiency slightly decreased to 39.1% with the increase of the nanotube content. The smallest value of unit energy consumption was achieved for the extrusion (at 150 rpm) of a material contg. 2% halloysite. The screw rotating at 50 rpm resulted in a significant redn. in the efficiency of the process as well as in significant increase in the unit energy consumption for the tested materials.

14

Foaming extrusion of thermoplastic polyurethane modified by POSS nanofillers

Stachak Piotr, Hebda Edyta, Pielichowski Krzysztof

Composites Theory and Practice

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2019

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R. 19, nr 1

23--29

EN

Thermoplastic polyurethane elastomers (TPU), having mechanical properties similar to chemically crosslinked rubbers, can be processed using extrusion or injection molding techniques. Combining extrusion with a foaming process leads to the fabrication of porous lightweight materials with novel properties. These properties can be further modified by applying additives, such as polyhedral oligomeric silsesquioxanes (POSS). POSS are organic-inorganic hybrid nanofillers that could enhance polymer-based composites properties, e.g. mechanical properties or thermal stability. In this work, the foaming extrusion process of TPU, utilizing azodicarboxamide (ADC), sodium bicarbonate (SC) and citric acid monohydrate (CA) as blowing agents (or their mixtures) was described. TPU was modified with two kinds of POSS nanofillers: TMP DiolIsobutyl POSS (TMP POSS) and trans-Cyclohexanediol Isobutyl POSS (TC POSS) to intensify the nucleation of the foaming process and to improve the thermal properties of the TPU matrix. A suitable processing window was determined by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The relations between the type of blowing agent mixture, POSS nanofillers and microstructure/thermal properties of TPU porous composites were evaluated using DSC and scanning electron microscopy (SEM). The blowing agent mixtures, which produce solid residue after decomposition (ADC-CA and CA-SC), influence the nucleation process in the crystalline domains of TPU. The addition of POSS nanofillers strengthens the abovementioned effect and additionally increases the amount of pores in the extrudates, as well as enhances their shape stability.

PL

Termoplastyczne elastomery poliuretanowe (TPU), o własnościach mechanicznych podobnych do chemicznie usieciowanych kauczuków, mogą być przetwarzane za pomocą technik wytłaczania lub formowania wtryskowego. Połączenie wytłaczania z procesem spieniania prowadzi do wytworzenia porowatych lekkich materiałów o nowych właściwościach. Te właściwości można dalej modyfikować przez zastosowanie dodatków, takich jak wielościenne oligomeryczne silseskwioksany (POSS). POSS są organiczno-nieorganicznymi hybrydowymi nanowypełniaczami, które mogą polepszyć właściwości kompozytów polimerowych, np. właściwości mechaniczne lub stabilność termiczną. W pracy opisano proces wytłaczania porującego TPU z użyciem azodikarboksyamidu (ADC), wodorowęglanu sodu (SC) i monohydratu kwasu cytrynowego (CA) jako środków porotwórczych (lub ich mieszanin). TPU zmodyfikowano dwoma rodzajami nanowypełniaczy POSS: TMP DiolIsobutyl POSS (TMP POSS) i trans-Cyclohexanediol Isobutyl POSS (TC POSS) w celu zintensyfikowania procesu nukleacji podczas porowania i poprawy właściwości termicznych matrycy TPU. Wyznaczenie odpowiedniego okna przetwórczego przeprowadzono za pomocą różnicowej kalorymetrii skaningowej (DSC) i analizy termograwimetrycznej (TG). Zależność między rodzajem mieszaniny środków porotwórczych, nanowypełniaczami POSS a właściwościami mikrostrukturalnymi/termicznymi porowatych kompozytów TPU oceniano za pomocą DSC i skaningowej mikroskopii elektronowej (SEM). Mieszaniny środków porujących, które wytwarzają stałą pozostałość po rozpadzie (ADC-CA i CA-SC), wpływają na proces nukleacji w krystalicznych domenach TPU. Dodanie nanowypełniaczy POSS wzmacnia wyżej wspomniany efekt i dodatkowo zwiększa ilość porów w wytłoczynach, a także zwiększa ich stabilność kształtu.

15

Numerical analysis and experimental validation of conjunction gear via hot forging-upsetting finishing-radial extrusion

Li Shilin, Ji Hongchao, Wang Baoyu, Mu Yanhong

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 2

391--404

EN

Numerical analysis and experimental validation of conjunction gear via hot forging-upsetting finishing-radial extrusion

16

Effect of Nature and Amount of Polypropylene Composite Filler on the Productivity of Extruder with the Cylinder Equipped with Grooves

Krasinskyi Volodymyr, Moravskyi Volodymyr, Suberlyak Oleh, Sikora Janusz W., Jachowicz Tomasz

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 4

264--269

EN

The effect of grooves number in the feed section and screw length as well as filler nature and content on the productivity of single-screw extruder has been examined. Compositions based on polypropylene with glass fibers, talc and chalk were used for research. It is established that the number of grooves in the feed section and the length of the screw differently affect the productivity of a single screw extruder depending on the nature and content of the filler. This effect is shown to be most significant for polypropylene compositions with mineral powders (talc and chalk).

17

Uogólniony model uplastyczniania tworzyw polimerowych w procesie wytłaczania

Lewandowski A., Wilczyński K.

Polimery

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2018

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T. 63, nr 6

444--452

PL

Przedstawiono uogólnioną metodę modelowania uplastyczniania tworzyw polimerowych w procesie wytłaczania, niezależną od sposobu wytłaczania i niewymagającą znajomości mechanizmu uplastyczniania. Proponowana metoda polega na modelowaniu przepływu dwufazowego (płyn/ciało stałe) jako przepływu jednofazowego, w którym materiał występuje w stanie stałym lub płynnym, w zależności od warunków przepływu. Zastosowano równanie reologiczne Crossa-WLF (Williamsa-Landela-Ferry’ego), umożliwiające zdefiniowanie tworzywa w stanie stałym jako płynu o dużej lepkości, natomiast tworzywa w stanie uplastycznionym jako płynu o małej lepkości. Zagadnienie rozwiązywano w odniesieniu do wytłaczania jednoślimakowego, z założeniem przepływu nienewtonowskiego, trójwymiarowego, nieizotermicznego, z zastosowaniem narzędzi obliczeniowej mechaniki płynów (ang. CFD, Computational Fluid Dynamics). Przebieg uplastyczniania był definiowany przez rozkład temperatury płynu, wyznaczający obszar ciała stałego i obszar płynu.

EN

A procedure of general modeling of polymer melting in extrusion process has been presented. The procedure is independent on the type of extrusion, and does not require any knowledge of melting mechanism. The procedure involves modeling the two-phase flow (fluid/solid) as a single-phase flow in which the material, depending on the flow conditions, is solid or fluid. Cross-WLF rheological model has been used, which defines the solid polymer as a high viscosity fluid, while the polymer melt as a low viscosity fluid. The problem has been solved for single screw extrusion process as a three-dimensional, non-isothermal, non-Newtonian flow using CFD (Computational Fluid Dynamics) software. Melting progress is defined by the temperature distribution which determines the regions of solid and fluid.

18

Microstructure and Mechanical Properties of Duplex Structured Mg-Li-Zn-Y Alloys

Su J., Yang Y., Fu X., Ma Q., Ren F., Peng X.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

181--185

EN

As-cast Mg-6Li-0.3Zn-0.6Y and Mg-6Li-1.2Zn-1.2Y (wt%) alloys were prepared and extruded at 260 ºC with an extrusion ratio of 25. The microstructure and mechanical behavior of as-cast and extruded alloys are reported and discussed. The results show that Mg-6Li-1.2Zn- 1.2Y alloy is composed of α-Mg, β-Li, and W-Mg3Zn3Y2 phases while Mg-6Li-0.3Zn-0.6Y alloy contains α-Mg, β-Li, W-Mg3Zn3Y2 phase and X-Mg12ZnY. After hot extrusion, the microstructure of specimens is refined and the average grains size of extruded alloys is 15 μm. Dynamic recrystallization occurs during the extrusion, leading to grain refinement of test alloys. Both the strength and elongation of test alloys are improved by extrusion. The extruded Mg-6Li-0.3Zn-0.6Y alloy possesses an ultimate strength of 225 MPa with an elongation of 18% while the strength and elongation of Mg-6Li-1.2Zn-1.2Y alloy are 206 MPa and 28%, respectively. The X-phase in Mg-6Li-0.3Zn- 0.6Y is beneficial to the improvement of strength, but will lead to the decrease of ductility.

19

Numerical simulation of the design of extrusion process of polymeric mini-tubes

Białasz Sebastian, Pamies Ramon

Applied Computer Science

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2018

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Vol. 14, no 3

81--95

EN

In this paper we represent a study reporting the numerical simulation of small-diameter pipes extrusion process. Polypropylene and low density polyethylene were chosen as plastics and a selected transverse head as a tool in the simulations. The aim of the study is to examine the distribution of temperature in the individual sections of the bagasse and tools, in order to optimize the parameters and process flow extrusion and validate the implementation tools, by simulating the flow of plastic by the head.

20

Comparative Analysis of the Impact of Die Design on its Load and Distribution of Stress During Extrusion

Nowotyńska Irena, Kut Stanisław

Applied Computer Science

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2018

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Vol. 14, no 4

25--33

EN

In the paper a numerical comparative analysis of stresses in a steel die compressed by a ring during the extrusion process was presented. In the research, three design solutions of the die were used. The solutions vary depending on the quotient of the wall thickness of the die insert and the wall thickness of the compression ring while maintaining a constant tool diameter. The stresses occurring in the areas of the ring and the die were calculated depending on the design version of the tool and the pressure value. The analysis was carried out for the quotients of the die wall thickness to the ring wall thickness of 0.57, 1 and 1.75 and three press-in values of 0.004, 0.008 and 0.016 mm. The conducted research allowed determining the impact of the die design and assembly interference on the load bearing capacity. It was discovered that the use of a die insert with a smaller thickness com-pared to the thickness of the compression ring was the most advantageous from the point of view of the circumferential stresses.