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EN
The analysis of polymeric composites can be quite challenging because the samples are often of complex nature due to the presence of various groups of additives, compounding ingredients, and fillers. In this contribution, changes of hardness of Polypropylene (PP) composites during and after the exposure of materials to UV chamber and low temperatures were investigated. The particulate fillers talc and chalk in weight fraction from 10 to 50% and montmorillonite (MMT) in weight fraction 4% were used as fillers in the polypropylene matrix. The composites were mixed in the extruder while the length, diameter of screw, as well as the number of grooves in the feed zone were changed. The influence of ageing – UV radiation and low temperature was examined by change of Shore hardness after 360h and 720h of exposure. According to the performed tests we can conclude that the tested materials may be exposed to UV radiation and low temperature of -20ºC without significant changes of hardness.
EN
In recent decades, standard polymer blends for different applications have been more and more often replaced by blends containing raw materials. The use of natural materials as filler in thermoplastics brings both economic and environmental benefits. The use of a given vegetable filler depends on the geographic location and natural occurrence of the vegetables in a given geographic region. In Poland, for instance, the pumpkin is one of such vegetables. They are used for producing oil which is pressed from pumpkin seeds. Pumpkin seeds are then collected, dried and purified to produce waste material in hull form. Particles of ground pumpkin seed hulls with varying sizes and weight-in-weight concentration ranging from 0% to 20% relative to the matrix are used as filler in low-density polyethylene. Pumpkin seed hulls are ground and sieved. Four fractions of hulls with different particle sizes are produced: <0.2 mm, 0.2-0.4 mm, 0.4-0.6 mm, 0.6-0.8 mm. The paper reports the results of investigation of the mechanical properties, i.e., strength properties determined by static tensile testing and hardness measurement, of injection molds produced at constant processing parameters. In addition, the cross sections of the obtained products are subjected to microscopic examination. Relationships are determined between tensile modulus, maximum tensile stress, tensile stress at yield, maximum tensile strain, tensile strain at yield as well as Shore hardness and weigh-in-weight concentration of the powdered natural filler and its grain sizes. Finally, relevant conclusions are drawn.
EN
The aim of study is to assess the technology review of plastic mold parts and to propose the modification of its production. Analyzes were performed by simulation program Moldflow Plastic Advisor (MPA) and two alternative constructional solutions were proposed. Results of the simulation are technologically optimized mold parts and technological parameters for its production.
PL
Celem badań jest przeprowadzenie oceny przebiegu różnych sposobów otrzymywania wtryskiwanych wyprasek z tworzyw polimerowych i zaproponowanie technologii ich produkcji. Zostały przeprowadzone analizy komputerowe dwóch alternatywnych rozwiązań konstrukcyjnych wypraski za pomocą programu do symulacji Moldflow Plastic Advisor (MPA). Otrzymane wyniki symulacji optymalizują technologiczność konstrukcji wyprasek, jak i parametry technologiczne ich wytwarzania.
EN
Nowadays designers and engineers readily turn to plastics because they offer combinations of properties not available in any other materials. Plastics offer advantages such as lightness, resilience, resistance to corrosion, colour fastness, transparency, ease of processing, etc., and although they have their limitations, their exploitation is limited only by the ingenuity of the designer. Degradation of the polymers under the influence of temperature, light, humidity and oxygen leads to changes in structures such as the increase in crosslinking, reducing the degree of polymerization, oxidation or recrystallization of the molecular chains. The result of the ageing process are reversibly or irreversibly a deterioration of processing and changing of properties. The aim of this paper was the comparison of change of selected properties of polymer composites used for the production of parts in the electrical industry in changing the thermal conditions. Materials ABS, PA6 and PBT were tested and the samples were exposed to different climatic conditions. Static tensile test and 3- point bend test were used for testing and samples were used by injection molding.
PL
Obecnie projektanci i inżynierowie chętnie sięgają po tworzywa sztuczne ze względu na kombinacje właściwości, które oferują, nieosiągalne w przypadku innych materiałów. Tworzywa mają liczne zalety, takie jak: lekkość, sprężystość, odporność na korozję, trwałość koloru, przejrzystość, łatwość obróbki, itd. i mimo swoich ograniczeń, ich zastosowanie jest ograniczone tylko poprzez pomysłowość lub jej brak u projektanta. Degradacja polimerów pod wpływem temperatury, światła, wilgotności i tlenu prowadzi do zmian w strukturze, takich jak wzrost sieciowania, redukcja stopnia polimeryzacji, utlenianie czy też rekrystalizacja łańcuchów molekularnych. Skutki procesu starzenia to odwracalne bądź nieodwracalne pogorszenie przetwarzania i zmiana właściwości. Celem niniejszej pracy było porównanie zmian wybranych właściwości kompozytów polimerowych stosowanych w produkcji części w przemyśle elektrycznym przy zmieniających się warunkach termicznych. Badano materiały ABS, PA6 PBT, których próbki poddani działaniu różnych warunków klimatycznych. W badaniach wykorzystano statyczne próby rozciągania oraz 3-punktowy test giętkości, natomiast próbki były wykorzystane w procesie formowania wtryskowego.
PL
Przedstawiono wyniki badań doświadczalnych dotyczących zmian charakterystyki p-v-T polipropylenu o różnych zawartościach napełniacza mineralnego. Wyznaczono współczynniki modelu matematycznego opisującego zmianę objętości właściwej w zależności od temperatury i ciśnienia, mającego zastosowanie w symulacji numerycznej procesu wtryskiwania i skurczu.
EN
Polypropylene was filled with CaCO3 (10–30%) and studied for pressure-vol.-temp. characteristics under 20–120 MPa at 25–240°C. The exptl. data were approximated with the Renner model.
6
PL
Podczas prowadzonego procesu wytwarzania porowanych powłok kabla wykonano badania termowizyjne wytwarzanych taśm, których celem było określenie wpływu oddziaływania środków porujących egzotermicznie oraz endotermicznie na temperaturę tworzywa porowanego opuszczającego głowicę wytaczarską. Do badań termowizyjnych procesu wytłaczania porującego wykorzystano kamerę termowizyjną V-20. Umożliwia ona zdalne bezkontaktowe rejestrowanie rozkładu temperatury na powierzchniach badanych obiektów oraz umożliwia wykonywanie pomiaru temperatury w zakresie od -10 do 500°C. Badanymi obiektami podczas prowadzonego procesu wytłaczania były głowica wytłaczarska oraz porowana taśma po wyjściu z głowicy wytłaczarskiej. Analizę otrzymanych wyników pomiarów przeprowadzono za pomocą specjalnego programu komputerowego Therm V20. W wyniku tych pomiarów otrzymano obrazy termalne głowicy wytłaczarskiej oraz powłoki porowatej przy zwiększanym dozowaniu środka porującego. Przykładowe obrazy termalne zostały przedstawione na rysunkach 2 i 3.
EN
The experimental tests of producing cellular tapes involved performing the infrared mapping examination of produced tapes in order to determine the effect of the exothermic and endothermic blowing agents on the temperature of the cellular polymer that was leaving the extruder head. To perform the infrared mapping examination of the foaming extrusion process, a V-20 infrared camera was used. The camera enables the remote, contact-free recording of temperature distribution on surfaces of examined objects, allowing for measuring temperature in the range from -10 to 500°C. The extruder head and cellular tapes leaving the extruder head die were the objects examined in the course of the process. The infrared camera was distanced from the examined objects by 0.4 m. The results were analyzed using specialist computer programme Therm V20. As a result of the measurements made, thermal images of the extruder head and cellular coating at increasing blowing agent doses were obtained. The examples of the thermal images are shown in Figures 2 and 3.
EN
This paper deals with determination of optimal injection molding process parameters by DOE technique. Taguchi’s orthogonal table was applied to plan the simulation and the experiments. For this study plastic simulation of injection molding for specimens made of fiber glass filled PBT was performed . Determination of the optimal process parameters was based on RSM surface with goal of minimization moldings warpage. Five controlling factors of melt temperature, coolant inlet temperature, injection and packing and cooling time, packing pressure and packing time with three levels for each factor were selected. According to the results, melt temperature is the most important parameter for both moldings. Injection time and coolant inlet temperature had no significant effect on the shrinkage of either moldings.
PL
Artykuł skupia się na określeniu za pomocą metody DOE optymalnych parametrów procesu formowania wtryskowego. Do planowania symulacji i eksperymentu zastosowano ortogonalną tablicę Tagucjiego. Symulację wykonano dla procesu formowania wtryskowego włókna szklanego wypełnionego tworzywem PBT. Optymalne parametry procesu zostały przedstawione za pomocą tzw. „powierzchni odpowiedzi” (RSM) w celu określenia minimalnego zwichrowania wyprasek. W badaniach uwzględniono pięć parametrów sterowalnych: temperaturę wtrysku, temperatura chłodziwa, czas wtrysku-docisku-studzenia oraz ciśnienie i czas docisku. Wartości tych parametrów podzielono na trzy poziomy. W odniesieniu do wyników, temperatura wtrysku jest najważniejszym parametrem. Natomiast czas wtrysku oraz temperatura chłodziwa nie mają istotnego znaczenia na skurcz wypraski.
EN
In recent years, cellular extrusion of polymers has been one of the fastest growing processing methods. It is used especially to obtain sections, bars, pipes and cellular coatings free from strains on the product surface, displaying reduced density and minimum shrinkage, at the same time maintaining similar properties of products extruded in a conventional way. In order to obtain cellular structure, product properties are modified by application of proper plastics or adding blowing agents. The article provides a description of manufacturing processes of cellular product. It gives characteristics of blowing agents used in the extrusion process and of processing conditions. Also, it discusses selected results of examined properties of the obtained cellular products. As part of the modernization of the cellular extrusion technology the extrusion head was designed and made. During the designing and modeling of the head the Auto CAD programe was used. After the prototyping the extrusion head was tested. In the article specification of cellular extrusion process of thermoplastics was presented. In the research, the endothermal chemical blowing agents in amount 1,0% by mass were used. The quantity of used blowing agent has a direct influence on density and structure of the extruded product of modified polymers. However, these properties have further influence on porosity, impact strength, hardness, tensile strength and another.
9
Content available Effectiveness of cellular injection molding process
EN
In a study of cellular injection, molding process uses polyvinylchloride PVC. Polymers modified with introducing blowing agents into them in the Laboratory of the Department of Technologies and Materiase of Technical University of Kosice. For technological reasons, blowing agents have a form of granules. In the experiment, the content of the blowing agent (0–2,0% by mass) fed into the processed polymer was adopted as a variable factor. In the studies presented in the article, the chemical blowing agents occurring in the granulated form with a diameter of 1.2 to 1.4 mm were used. The view of the technological line for cellular injection molding and injection mold cavity with injection moldings are shown in figure 1. The results of the determination of selected properties of injection molded parts for various polymeric materials, obtained with different content of blowing agents, are shown in Figures 4–7. Microscopic examination of cross-sectional structure of the moldings were obtained using the author’s position image analysis of porous structure. Based on analysis of photographs taken (Figures 7–9) it was found that the coating containing 1.0% of blowing agents is a clearly visible solid outer layer and uniform distribution of pores and their sizes are similar.
PL
Wskaźnik szybkości płynięcia (MFI) jest istotnym elementem składowym ogółu informacji odnoście tworzyw polimerowych wskazujących metodę przetwórstwa. Stanowi on też pewną wskazówkę przy doborze parametrów technologicznych w tym procesie. Wartość MFI jest podawana przez wszystkich producentów granulatów tworzyw termoplastycznych z przeznaczeniem do produkcji wszelkich przedmiotów wprowadzanych na rynek do sprzedaży i jest jednym z kluczowych wskaźników klasyfikującychtworzywa termoplastyczne. W pracy zaprezentowano wyniki badań wskaźnika szybkości płynięcia, jako szczególnej właściwości fizykochemicznejtworzyw termoplastycznych, dla kompozytów termoplastycznych na bazie polipropylenu połączonego z ciętym włóknem szklanym oraz talkiem w różnych ilościowo proporcjach.
EN
Melt flowindex (MFI) is an important component of the total information indicating right method of polymer processing. It is also a hint in the selection of technological parameters in the process. MFI value is given by all manufactures of thermoplastic granules for the processing of any object placed on the market for dale. This is one of the key indicators for classificationof thermoplastic materials. The paper presents results of the melt flowindex, as a specificphysicochemical properties of thermoplastic. In the paper are the results for thermoplastic composites based on polypropylene with a short cut glass fiber and talc in various amounts.
11
Content available remote The new trends in design moulds for plastic
EN
The paper presents new trends and new materials used in the design of moulds for plastics processing. Application of CAD / CAM / CAE systems reduces the time of the design of forming tool. Tool materials produced by new technologies are compared with standard materials. Wear of tool materials were examined for plastics injection molding. Simulation of technology of plastic injection molding process was examined as a tool to improve the quality of plastic parts.
12
Content available remote The influence of amount of filler on mechanical properties for electro products
EN
In order to favorably influence some product manufacture qualities of plastics (an increase of mechanical properties, chemical resistance, etc.), or by reason of reduction in price of finished plastic product, the fillers are added to plastic materials. The contribution deals with the change of mechanical properties of selected types of plastics with different % of glass filler. The mechanical properties were measured by tensile test and Charpy impact test in a standard ambient and after degradation of materials by UV radiance. The fracture areas of studied materials were observed on scanning microscope.
13
Content available remote Evaluation of some mechanical properties of steel sheet
EN
The requirement for reducing of weight of products urges the producers to reducing thickness of used materials. It means the reducing of thickness of products from sheet. The second requirement for product is its adequate stiffness. These requirements force product manufacturers from sheet material to ask for development of sheets with higher strength properties and formability from sheet producers. The properties of sheet must guarantee deep- drawing of stampings without problems, but with required qualitative and dimensional parameters. The contribution solves the problem of deep drawing of bath tubes and pressability of steel sheets used at the production of bath tubes. The thickness of used steel sheets were changed from 1,55 mm to presented 1,35 mm. This change had an influence on the required properties of steel sheets and also the changes of technological conditions of deep drawing. The next surface finishing of pressing - bath tube requires the roughness of surface in the defined boundary.
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