Papers by Keyword: Extrusion

Abstract: Pellet additive manufacturing (PAM) is in terms of printing process very similar to the widely used fused deposition modelling (FDM) systems. The main difference is the use of pellets instead of filament. In this study, a pellet, single screw extruder is developed. A screw design with variable pitch and depth is modelled analytically to predict the melting behavior of acrylonitrile butadiene styrene (ABS) during steady state extrusion. The extruder screw was designed unconventionally short with a length of 85 mm and a diameter of 20 mm, giving an L:D ratio of 4.25:1. The model predicted the melting profile for ABS being extruder at 235°C at 10 RPM, the result of which was confirmed to a degree by experimentation. The extrusion rate of the screw extruder was measured at barrel temperatures of 225°C to 245°C with 5°C increments and at 5 RPM and 10 RPM. The extrusion was found to increase non-linearly with barrel temperature and screw speeds. The extruder printed adequately on an FDM style motion system with minor upgrades.

Abstract: In the trend of unconventional oil and gas explorations, the long laterals over 3,000 m are commonly fractured in multistage fracturing operations. The mill-out of the conventional and temporary isolation downhole tools, such as frac plugs or balls/ball seats, in these wells using mechanical intervention, such as coiled tubing (CT), is a challenge. This paper is to review the developments of the dissolvable alloys to be used on these tools in these long lateral wells to eliminate the mechanical intervention afterward. It includes the history and current status of the developments of the dissolvable alloys. The two types of mainstream dissolvable alloys including magnesium-based and aluminum-based alloys were developed, based on their microscale galvanic corrosion behaviors. The properties of these dissolvable alloys, therefore, depend on the chemistry, process and finally microstructure. The casting and extrusion processes will be discussed since they are very important processes to enhance properties of the dissolvable alloys. The properties including the strength, the ductility and the dissolvability are measured under various temperatures, pressures and salinities conditions. The future trend of development is also briefly visioned.

Abstract: The paper considers the dependence of the strength properties of 3D-printed parts on FDM printing modes (temperature and speed), as well as the layer arrangement. PETG (polyethylene glycol terephthalate) based filament was chosen as the basis. A 3D printer was used to produce samples with strictly defined orientation of layers — longitudinal and transverse tensile force at different temperature and printing speed. The experiment has established the effect of these two factors on the tensile strength. The strength of the samples printed transversely was higher than the strength of samples printed longitudinally. This indicates a higher interlayer adhesion.

Abstract: The use of thermoplastic starch in compositions based on polylactic acid is of interest from the point of view of controlling the physicomechanical properties of materials and the time of biodegradation. The effect of thermoplastic starch containing sorbitol and / or glycerin as plasticizers on the resistance of compositions based on polylactic acid to thermal and thermomechanical action was studied. The physicomechanical properties of the compositions and their resistance to biodegradation under composting conditions have also been determined.

Abstract: This paper is devoted to the study of the technological process for the production of tape from polyethylene and wood-polymer composite by extrusion. At the first stage, the wood-polymer composite granulate was obtained on a co-rotating twin-screw extruder. The tape was made on a Rheomex 19/25 PolyLab OS single-screw extruder with a barrel length L/D = 25. The processing temperature of the wood-polymer composite was in the range of 145 ... 160°C. The tensile strength and elasticity modulus in tension, water absorption per day and density were investigated for the developed wood-polymer composite and polyethylene. It has been found out that for the developed wood-polymer composite, the strength and elastic modulus along the stretch direction increase by 11% and 6%, respectively. Orientation stretching has a significant effect on the physical and mechanical properties of wood-polymer composites.

Abstract: A metal extrusion was process that extrusion puncture perforate surface of material to throw and flow across outlet of die. This operation was a complex process in extrusion while penetration occurred at same time. This process can be seen in many production operations, like in forming of making portion of metal strip, and forming of extruded portion in a complex fineblanking with extrusion operation. Also exhibit the operation properties and give the method of numerical solution. So increasing load to 610KN with increased friction factor to 0.7 and increased with increasing the reduction ratio and stroke of operation. For the results and mesh distortion, with allocations of strains may be predicted. Analyzing results was submitted of metal extruded may be classified into two zones for the different lineaments deformation. moreover, energy in the zones of deformation may be classified into two parts for their different lineaments of internal zone and contact zone with the die . Fracture location has been found from simulations. Keyword Load, Extrusion, upper bound, numerical solution

Abstract: The effects of coarse-grained ring on the mechanical properties and cutting performance of 2011 aluminum alloy extruded bars were studied by metallographic microscope, scanning electron microscope, tensile testing machine and high-speed lathe. The results show that the microstructure of aluminum alloy extruded bar was composed of α-Al phase, Al₇Cu₂Fe phase, CuAl₂ phase and SnBi eutectic phase. There was a coarse-grained ring in the aluminum alloy extruded bar. The coarse-grained ring reduced the mechanical properties and cutting performance of the aluminum alloy extruded bar. The aluminum alloy extruded bar with a diameter of 30 mm had a coarse-grained ring depth of 9 mm and lower mechanical properties, whose the tensile strength was 287.9 MPa, the elongation was 17%, the cutting performance was poor and the chips were long. The aluminum alloy extruded bar with a diameter of 40 mm had a coarse-grained ring depth of 1 mm, higher mechanical properties and better cutting performance, whose the tensile strength was 394.5 MPa, the elongation was 23.5%, the chips were fine and uniform.

Abstract: Investigating the influence of process parameters is vital to improve the mechanical properties of nanoparticle reinforced polymer nanocomposites. In this effort, nanocomposites of polypropylene/nanoclay are prepared by the extrusion method. In order to characterize the mechanical behavior of nanocomposites over different compounding ratios, samples are prepared with 5 and 10 wt%. Effect of re-extrusion and PP-g-MA compatibilizer on the tensile performance of nanocomposites is evaluated at different strain rates. XRD evaluation of compounds indicated that re-extrusion is an important factor in increasing the exfoliation degree.

Abstract: Cold extrusion is an established technology for the production of dimensionally accurate components in large series. Due to the high material and energy efficiency, a resource-saving manufacturing of high-performance parts is possible. Forming at room temperature leads to an advantageous grain structure and work hardening of the material, resulting in components with favorable operating characteristics. Nevertheless, a challenge is the generation of residual stresses during forming, which are influencing the fatigue behavior. The modification of the tribological conditions is one method for influencing the parts’ residual stress state. However, the high strength and work hardening of the materials formed at room temperature leads to high tribological loads between billet and die. These challenges are intensified by the increasing use of stainless steels due to growing demands for corrosion resistant components. The aim followed within this paper is therefore to investigate the applicability of typical lubricant coatings in the forward rod extrusion of stainless steels. For this purpose, the ferritic stainless steel X6Cr17 (DIN 1.4016) and the ferritic-austenitic stainless steel X2CrNiMoN22-5-3 (DIN 1.4462) are extruded with an equivalent plastic strain of ε̅ ≈ 1. The research is performed with a molybdenum disulfide (MoS₂), a soap and a polymer-based lubricant coating. For reproducing different contact conditions, the die geometry is varied with die opening angles of 60°, 90° and 120°. The suitability of the lubricants is evaluated using the integrity of the lubricant coating after forming. From the correlations between process forces, temperatures and surface integrity, recommendations for the application of the researched lubricants are derived.

Abstract: Fly ash is the waste product coming out from thermal power plant is an increasingly urgent problem due to its storage and disposal. At the same time Metal Matrix composites (MMCs) reinforced with ceramic particles such as SiC, Al₂O₃ and B₄C has their partial use in engineering application due to higher cost. The study focuses on the Al-Cu alloy reinforced fly ash particles produced by stir casting followed by hot extrusion. The composites produced by incorporation of fly ash reinforcements by varying 2%, 4%, 6%, 8% and 10wt% is hot extruded with an extrusion temperature of 400°C, extrusion rate of 5mm/s and extrusion ratio of 1.77:1. The extrusion composites have been evaluated based on the investigation of mechanical properties and microstructure. The results showed that, the amount of porosity increased with increasing the percentage of fly ash reinforcements in stir cast and the extruded composites is almost gratis from porosity. Hardness and tensile strength of composites increases with increases in percentage of reinforcement by stir and extruded composites. But extruded composites show better mechanical properties than stir cast composites. Wear test under different loads and for 45 minutes duration have been conducted on both cast and extruded composites. The worn surfaces have been observed under Scanning electron microscope (SEM) to understand the mechanism of wear. Extruded composites possess lower wear rates under all studied loads with constant sliding velocities when compared with cast composites. Microstructural study using SEM shows that the fly ash particulates in the molten matrix forms strong matrix reinforcement interface and their distribution might have led to the increase in mechanical properties of the composites due to fine grain structure during extrusion and dislocation density in the matrix.