Large Plastic Parts Research Articles

RESEARCH ON THE TECHNOLOGY OF PREPARING PLASTIC AND THREADED COMPONENTS USING 3D PRINTING OR ADDITIVE MANUFACTURING

Threaded components play a crucial role in ensuring the safety and reliability of systems by joining components together. Proper selection of thread type and size, ensuring proper machining and storage of components, and addressing potential issues such as leakage, vibration, and misalignment all play a special role. It is known that there is a big difference in the nature of the destruction of metal and plastic threaded connections, in particular, when the nut is made of plastics, and the bolt is made of steel, or vice versa. In this regard, at present there is no consensus in assessing the strength of plastic threaded connections. On the one hand, it is recognized that, due to a more uniform distribution of the load, plastic threaded connections have a significant load capacity. Numerous examples of the use of plastic threaded connections in pressure pipelines, in large plastic parts subjected to dynamic loads, various loaded fasteners - all these examples confirm that plastic threaded connections can withstand very high loads. Production of a thread of plastic details is rather difficult, than on metals. It is connected with the physical-mechanical processes coming in the course of production of concrete thread details from plastic by method of pressing and casting under pressure. Also mechanics of formation of plastic threads on details of the oil-field equipment on the specific properties differ from the threads received by a machining method on metals. As thread surfaces on plastic details are formed in compression molds depending on materials and the modes: temperatures, pressure and time of production. These regime parameters and guided parameters play a part at a guaranty of physicalmechanical properties of details in the course of production. The use of plastic or polymer threads in the oil and gas industry is increasing due to their unique characteristics and advantages over traditional metal threads. Recently, 3D printing (additive manufacturing) has become more widely used for the preparation of plastic threads. The article will discuss the methods and characteristics of preparing plastic threaded components, as well as their advantages and certain incompatibilities. Keywords: threaded components, plastic threaded components, preparation methods, 3D and 4D printing.

Micro-injection molding using a polymer coated mold

We applied an insulating polymer layer to the surface of mold cavity to injection-mold large plastic parts with a microsized thickness. Polyimide (PI) was coated on the mold wall using spray coating method. A thin light guide plate (LGP) was designed and fabricated via micro-injection molding. The polymeric coating layer could enhance the fluidity of polymer melt in the cavity during filling stage by minimizing the formation of the skin layer during injection molding. The surface roughness and pattern transfer rate of the LGPs were analyzed experimentally. In addition, numerical simulation was carried out to understand the insulation effect of the layer in the injection molding.

Identification and assessment of product's measures to improve resource efficiency: the case-study of an Energy using Product

Abstract The article introduces the “Resource Efficiency Assessment of Products” (REAPro) method to assess and improve the resource efficiency of Energy Using Products, with a special focus to their end-of-life. The method allows to identify product's hot spots relevant for the following criteria: reusability/recyclability/recoverability (in mass and in terms of environmental impacts); recycled content (in mass and in terms of environmental impacts); use of hazardous substances. The method is structured into five steps: characterization of the product; assessment against the selected criteria; identification of product's hot spots; identification of improvement measures (at the product level); assessment of policy measures for resource efficiency (at the ‘product group’ level). The method includes the calculation of a comprehensive set of lifecycle based indices, including some original indices, as the “Reusability/Recyclability/Recoverability benefits rates” and the “Recycled content benefit rate”. The method is applied to a case-study Liquid Cristal Display (LCD) television. Some exemplary measures to improve resource efficiency of television are discussed as: the improvement of products recyclability through the setting of thresholds of the time for dismantling; the setting of a minimum recycled content of large plastic parts; the declaration of the content of indium in the displays. Potential environmental benefits associated to these measures have been estimated. The method also proved to be relevant to current European Union (EU) policies and some of the presented results are being used as input for some on-going policy processes.

The Influence of Processing on the Aesthetic, Morphological and Mechanical Properties of Structural Foam Mouldings of High- Impact Polystyrene

The production of large plastic parts, in small series and at low cost, requires the development of alternative tools and materials. Structural foams (SF) are an appropriate solution, when the production of thicker parts with superior properties is specified. They allow the production of lightweight parts with high stiffness and excellent dimensional stability, due to their sandwich-like structure consisting of a cellular core and two solid skins. The porous core is the result of the addition of a blowing agent in the polymeric matrix. These materials are applied in the urban furniture, automotive, nautical and aerospace industries. The most commonly used process to produce SF is low pressure foam moulding, which is a short-shot process, with impression pressures below 4 MPa. Therefore, the use of hybrid moulds with moulding blocks obtained by rapid prototyping routes is seen as a viable alternative for SF injection moulding. This work reports a study of the influence of processing conditions on the aesthetic, morphological, and mechanical properties of SF mouldings of high-impact polystyrene (HIPS-SF). The results compare the effect of the use of hybrid moulds to conventional moulds on the surface aspect of the circular centre-gated mouldings. Furthermore, the influence of the moulding temperature is ascertained in terms of the resulting cellular morphology, the flexural stiffness of the plate mouldings, and the impact resistance in the instrumented drop weight test.

Fatigue Source Analysis of Dynamic Mold Temperature Injection Mold for Large Plastic Parts

Dynamic mold temperature (DMT) injection molding is a molding process that the mold cavity is first rapidly heated to a high temperature before plastic melt injection, and then cooled quickly after filling and packing stages. With this technique, plastic parts with very good surface performance can be produced. However, as the special mold structure and its worse working process, large stress concentration can be caused in the mold. Consequently, the mold for this new injection technology can be easily fatigue and the lifetime of the mold is inevitably decreased. In this paper, the structure of the mold was presented first, and then the working process and factors influencing the lifetime of the mold were analyzed. Through numerical simulation, the fatigue source of the mold was evaluated. Results showed that the evaluation process presented in this paper was very in accordance with the practical failure mold.

Control Analysis of Production and Apparent Quality of Automobile Large Plastic Parts

Upon summarization and analysis of the structural features of automobile large plastic parts and the selection of corresponding shaping modes, this paper analyzes and elaborates product design, raw material selection, forming method, structural design of mode, and debugging of shaping process, etc. on account of manufacturing defects such as weld line and sink mark, etc. easily occurring to automobile large-scale plastic decorating parts subject to injection molding, and offers operable solutions and measures available for practical production for the sake of the maximum improvement of product apparent quality.

Design and FEM analysis of the milled groove insert method for cooling of plastic injection moulds

During an injection moulding process, it is very difficult to achieve efficient and balanced cooling. It is also difficult to generate an optimal cooling design for industrial parts automatically. In this paper, a milled groove insert method in mould cooling was proposed for cooling of medium and large plastic parts. The advantages of this method include a better cooling effect, ease and flexibility of design, characteristics of auto-design and considerable savings on the coolant flow rate. A household iron part was studied and the assemblies were modelled. The cooling analyses of the mould assembly and thermal stress analysis of plastic parts were performed using ABAQUS/Standard to compare the proposed method to the most popular straight-drilled cooling channel method. The thermal stress analysis was run, consequently, based on the result of the cooling analysis. Simulation results have confirmed the merits of the milled groove insert method.