Glass-filled Polyamide Research Articles

Comparative Evaluation of Tribological Effectiveness of Carbon- and Glass-Filled Polyamide Composites Using Submicromechanical Diagnostics of Surface Layers before and after Wear Tests during Dry Sliding Friction

Comparative Evaluation of Tribological Effectiveness of Carbon- and Glass-Filled Polyamide Composites Using Submicromechanical Diagnostics of Surface Layers before and after Wear Tests during Dry Sliding Friction

Evaluation of 3D Printed Burr Hole Simulation Models Using 8 Different Materials

3D printing is increasingly used to fabricate three-dimensional neurosurgical simulation models, making training more accessible and economical. 3D printing includes various technologies with different capabilities for reproducing human anatomy. This study evaluated different materials across a broad range of 3D printing technologies to identify the combination that most precisely represents the parietal region of the skull for burr hole simulation. Eight different materials (polyethylene terephthalate glycol, Tough PLA, FibreTuff, White Resin, BoneSTN, SkullSTN, polymide [PA12], glass-filled polyamide [PA12-GF]) across 4 different 3D printing processes (fused filament fabrication, stereolithography, material jetting, selective laser sintering) were produced as skull samples that fit into a larger head model derived from computed tomography imaging. Five neurosurgeons conducted burr holes on each sample while blinded to the details of manufacturing method and cost. Qualities of mechanical drilling, visual appearance, skull exterior, and skull interior (i.e., diploë) and overall opinion were documented, and a final ranking activity was performed along with a semistructured interview. The study found that 3D printed polyethylene terephthalate glycol (using fused filament fabrication) and White Resin (using stereolithography) were the best models to replicate the skull, surpassing advanced multimaterial samples from a Stratasys J750 Digital Anatomy Printer. The interior (e.g., infill) and exterior structures strongly influenced the overall ranking of samples. All neurosurgeons agreed that practical simulation with 3D printed models can play a vital role in neurosurgical training. The study findings reveal that widely accessible desktop 3D printers and materials can play a valuable role in neurosurgical training.

Laser powder bed fusion of glass-filled polyamide-composite with enhanced physical properties

Glass-filled polyamide (GF/PA) is an important engineering material for automotive industry because of its excellent physical, thermal and mechanical properties. But it is challenging to produce high quality functional parts through additive manufacturing technology like selective laser sintering (SLS). It is due to fact that SLS made parts exhibit high dependence on the sintering conditions. Thus, it becomes essential to adjust these sintering conditions accurately to improve physical properties like density and hardness to enhance the widespread use of this technology. Therefore, this study presents a statistical analysis of the SLS process parameters led by a design of experiment to extract information about their influence on hardness and density of the PA 3200 GF composite. GF/PA with a refresh rate of 60:40 was used for the part fabrication and the effect of five key sintering parameters has been considered for analysis. Experiments revealed that poor material integrity and weak interaction between the particles at lower energy density were the main reason for the lower hardness and density of fabricated parts.

Effect of packing pressure on stagnation weld-line strength for thermoplastic semicrystalline glass fiber reinforced material

Weld-Line in an injection molded part develops when two or more melt fronts are converged together. The weld-line is unavoidable when the design is complex where two melt flow fronts are mating each other head-to-head, this mating area is mechanically weak compared to other portions of the modeled part. The decrease in strength in the weld-line area can be attributed to several factors like molecular diffusion, fiber orientation effect, unoptimized process conditions, surface tension effect, internal residual stresses, etc. The strength of the weld-line area can be increased by optimizing injection molding process parameters like melt temperature, injection speed, packing pressure, changing gate type and location, etc. The present work focuses on studying the effect of packing pressure on strength of stagnation weld-line. This has been examined with experimental testing and scanning electron micrographs of the fractured surface on the weld-line and without weld-line specimens. The special injection mold is designed and fabricated to produce plaques having stagnation weld-line. The plaques are prepared out of 30% glass-filled Polyamide 6 material. The four sets of plaques are produced by changing the magnitude of packing pressure equal to 60% of filling pressure, with increment of 20% up to 120% of filling pressure. The tensile test specimens are machined on these plaques for two different angular orientations and testing is conducted as per ISO 527-2. The results demonstrated that, without weld-line specimens, the tensile modulus, stress at break marginally increases with an increase in packing pressure, and strain at break decreases with an increase in packing pressure. However, for specimens with stagnation weld-lines, both the tensile modulus and stress at break are observed to be 42% of without weld-lines samples for minimum packing pressure. The results obtained are evident from stress-strain graphs and scanning electron micrographs.

Application of Submicromechanical Diagnostics for Characterization of Glass-Filled Polyamide Composites

Application of Submicromechanical Diagnostics for Characterization of Glass-Filled Polyamide Composites

Numerical and Theoretical Analysis of a Spur Gear Using Composite and Conventional Materials

A spur gear is one of the most common forms of precision cylindrical gear. In the industry, reducing the weight of gears while keeping their useful properties has become an even more pressing challenge. As a result, the investigators have made many attempts to reduce the weight of the gears. Despite these efforts, the problem still requires more research. This study presented a spur gear's modeling and finite element analysis using different materials. A three-dimensional spur gear was designed, modeled, and simulated using ANSYS software. Five different materials, including two conventional materials (stainless steel and copper alloy) and three different composite materials, including 50% carbon fibers reinforced in epoxy resin, 1.5% filler containing acetal, i.e., Graphene Reinforced Acetal, and glass-filled polyamide. Composites were fabricated by varying the graphene quantity in Acetal nanocomposites. The spur gear stress was calculated theoretically using the Hertzian equation, and FEM was analyzed using ANSYS 14.0 under limited loading conditions and rotational speed. Although the obtained results showed that both methods were comparable, there was a significant difference between the two methods when 50% carbon fibers reinforced in epoxy resin matrix were used, which is Hertzian analysis was 250.13 MPa. In contrast, this result was reduced up to 152.13 MPa in FEM. The study concluded that among the different presented materials, 50% carbon fibers reinforced in epoxy resin matrix were the optimal material for spur gear fabrication due to their high strength and low density. Hence, the spur gear material can be replaced by 50% carbon fibers reinforced in the epoxy resin matrix.

ВПЛИВ ОСНОВНИХ ТЕХНОЛОГІЧНИХ ПАРАМЕТРІВ НА СТАБІЛЬНІСТЬ ПРОЦЕСУ ЛИТТЯ ПІД ТИСКОМ МУЛЬТИКОМПОНЕНТНИХ ВІДХОДІВ ПОЛІМЕРНИХ КОМПОЗИЦІЙ

In the work, a comparative analysis of the main technological parameters, as well as the stability of the injection molding process of the primary glass-filled (30%) polyamide 6 and the secondary composition of the mixture of glass-filled polyamide 6/polycarbonate was carried out.Non-standard multi-component car parts obtained on the hybrid casting machine "ENGEL" were used as the starting ma-terial. The black element of the part is cast from glass-filled polyamide (PA6GF30), the white element -from polycarbonate (PC). Grinding of parts was carried out by a mechanical method on a "Rapid 200" shredder. After mechanical processing, a mixture ofparticles was obtained from unseparated PA6GF30/RS components in the ratio of 90/10 wt.%. The granulate was used to cast the black component of the part without adding the original polymer composition on the "ENGEL" casting machine. Statistical data for determining the stability of the process and the machine were obtained using the Q Table software module. The results of the research were processed by the 6SIGMA method to obtain the appropriate indicators of process stability.It is shown that the use of the secondary mixture requiresan increase in the drying time and temperature, the parameter of the melt cushion in comparison with the primary material. At the same time, other parameters of the process did not undergo significant changes. At the same time, the stability of the casting process when using the secondary composition did not undergo statistically significant changes compared to the primary material and is within the permissible limits. The obtained resultsprove the possibility of reprocessing multicomponent waste polymer compositions by injection molding. This can reduce the cost of production by reducing the cost of raw materials, reduce the share of unprocessed polymer waste, and have a positive impact on the ecological aspects of the environment.

Ageing of laser sintered glass-filled Polyamide 12 (PA12) parts at elevated temperature and humidity

Additive manufacturing is traditionally used to manufacture either prototypes or very small-scale demonstrators. In recent years though, it is being increasingly used to make low volume parts for the aeronautical and defence industry. One concern with laser sintered parts is that their relatively porous nature, means that they may be more susceptible to ageing than injection moulded parts. Parts were aged for 6 months in at different temperatures (18°C, 40°C, 50°C, 60°C, 80°C and 100°C) and in a humidity chamber at 60°C and 80% relative humidity. Each month samples were removed for characterisation. The testing included tensile testing, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and gas pycnometry. During ageing the samples displayed visible discolouration and embrittlement over the 6-month test period. This embrittlement was not observed in those samples aged at room temperature or an elevated humidity. The observed yellowing in the samples aged above ambient temperature is likely a result of the build-up unsaturated degradation products. No significant differences as a result of ageing were observed via DSC, TGA, SEM or gas pycnometry.

Calculation of the stress – strain state of blades made of polymer composite materials of starting turboexpanders in resonance zones

An overview of the successful application of modern composite materials for the manufacturing of turbine blades of aircraft gas turbine engines, axial mine and blast furnace compressors. Their main advantages of these materials in comparison with metal are analyzed. Analytical calculations of stresses arising in the material of plastic blades of starting turboexpanders are carried out. The possibility of successful application of glass-filled polyamide for the manufacturing of moving and guide blades of starting turboexpanders and their successful operation at compressor stations of main gas pipelines is substantiated.

Processing and Characterization of Hollow Glass-Filled Polyamide 12 Composites by Selective Laser Sintering Method

ABSTRACT Selective Laser Sintering (SLS) is an accepted and improving technique for additive manufacturing in many different areas, from the applications of aerospace to automotive, consumer products to dental and medical materials. Lightweighting is a significant issue, especially in terms of the automotive and aerospace industries, mainly to increase fuel efficiency and reduce CO2 emission. The density reduction can be obtained by the addition of Hollow Glass Microspheres (HGMs) to Polyamide 12 (PA 12) polymer matrix. This study covers the different amounts of HGM filled PA 12 productions by SLS method and final structure characterization of PA 12-HGM composites. According to the performing thermal, physical, and mechanical tests, on increasing the amount of HGM in the structure, 10, 15, 20 weight percentages, respectively, the density of composites has been reduced significantly up to 20% for 20% of HGM filled PA 12 (PA 12–20HGM) composite, besides having a substantial rise in E-modulus.

Static and Dynamic Analysis of Selective Leverage System Gear Train

Nowadays, the mechanical advantage is strongly emphasized in a mechanical system. Therefore, the most modern gearboxes are used to increase the torque without also increasing their output speed while reducing it. In this study, Selective Leverage System (SLS) gear train is generated in Solidworks 2016 and together with dynamic motion study and static simulation analysis. Dynamic motion analysis is performed to provide output speed of SLS gear train. It can be concluded that the gear system runs with unchanged speed (RPM) for input and output which is approximately the same with theoretical value in Selective Leverage System patent. The maximum output torque is evaluated by using theoretical calculation. At every 90° rotation, maximum value of output torque is produced. The results are validated and compared to the analytical value of patent. For static simulation analysis, the stress distribution of T-shaped lever of Selective Leverage System gear train is identified by using composite material compared to the existing gear materials. The static simulation analysis between Aluminium Alloy, S45C Steel, Malleable Cast Iron and Glass Filled Polyamide are compared and composite materials are capable to be used as a material of gear train components instead of current material, S45C Steel for better result.

Study of polymer adhesion to steel

Tests on the dependence of glues shear strength on: gluing temperature, keeping time before testing, cooling environment, surface roughness, surface conditions, temperature and time of drying on air and in drying oven were carried out to select proper thermoplastics to use as glues for connection of steel elements together. The highest shear strength was showed by the following materials: desmopan 150, antifriction polyamide PA 610-L-DM, impact-resistant glass-filled polyamide. Given results allow significantly expanding scope of application of polymers as gluing compositions.

Effect of temperature on the fracture behavior of polyamide 12 and glass-filled polyamide 12 processed by selective laser sintering

The influence of the orientation and of the temperature on the mechanical properties of the polyamide 12 (PA12) and the polyamide 12 reinforced with glass beads processed via Selective Laser Sintering was analyzed. Tensile and fracture tests were performed at −50 °C, 23 °C and 50 °C with applied load perpendicular and parallel to the layered structure. The fracture resistance of PA12 was higher than that of the composite due to the poor adhesion of the glass beads to the matrix. The fracture behavior of the composite was unaffected by the temperature and the orientation. JIC values of PA12 were similar at −50 °C and at 23 °C and much lower than at 50 °C. The anisotropy was relevant during the stable crack growth.

Microstructural, thermal and rheological correlations to mechanical response of polyamide-6(glass filled)/polyetherimide blend: effect of ethylene-octene copolymer on toughening of blend

Melt mixed glass-filled polyamide 6(PA6)/polyetherimide (PEI) blends were prepared in a co-rotating twin screw extruder over the entire composition range of 0–100 wt% of polyamide 6. These blends were characterized by structural, rheological, mechanical and thermal properties. Crystallization behavior and phase morphology of the blends were also investigated. The blend with the composition PA6/PEI 75/25 showed overall improved mechanical properties along with low resultant viscosity which can be processed on standard equipment. Shear viscosity along with shear stress of the blends were analyzed using shear rheometer which concluded that the blends can be processed on standard equipment due to resultant low viscosity. Scanning electron microscope micrographs revealed that the morphology of the blends showed a two phase structure in which the minor phase was dispersed as domains in the continuous phase. Polyolefin elastomer (POE) as impact modifier was added to the above composition in the range of 0–15 phr to study its effect. The thermal characteristics of PA6, PEI, and PA6/PEI blends with and without POE were investigated using DSC and TGA which revealed that the melting temperature and crystallization temperature of the blend remained unchanged while XRD results showed percent crystallinity was increased slightly. Furthermore, it can be said that the blend with composition PA6/PEI 75/25 with 10 phr impact modifier loading was suitable for high end applications because it combines the high mechanical properties of glass-filled PA6 with inherent flame-retardant property of PEI while POE overcomes the physical weakness of moisture absorption.

Micromechanical Properties of Glass-Filled Polyamide 6

The process of radiation crosslinking helps to improve some mechanical properties of polymer materials. Micromechanical changes in the surface layer of glass-filled PA-6 modified by beta radiation were measured by instrumented test of microhardness. The specimens were prepared by injection technology and subjected to radiation doses of 0, 66, 99, 132 kGy. Measurements of microhardness showed considerable changes of behavior of surface layer in middle as well as high radiation doses with higher values of indentation hardness and stiffness.

Influence of Content of Crosslinking Agent on the Micromechanical Properties of Glass-Filled Polyamide 6

The process of radiation crosslinking helps to improve some mechanical properties of polymer materials. Some types of polymers do not cross-link during radiation crosslinking but degrade. In order to create 3D net in the polymer structure it is necessary to add a crosslinking agent. The specimens were prepared by injection technology with the TAIC crosslinking agent at 0, 1, 2 and 3 %. The changes of micromechanical properties of the surface layer were measured by instrumented microhardness test. It was found that micromechanical properties of the surface layer of the tested polyamide changed.

Experimental Investigation of SLS Process for Flexural Strength Improvement of PA-3200GF Parts

The strength of functional parts is of key importance in additive manufacturing, and the selection of proper parameters is essential to improve manufacturing solutions. Therefore, research is currently focused on determining the influence of process parameters (i.e., part bed temperature, laser power, scan speed, and scan spacing) on the flexural strength of laser-sintered glass-filled polyamide specimens. A response surface methodology-based mathematical model was proposed to predict flexural strength, and the adequacy of the developed model was verified thorough the analysis of variance technique. Further, optimized conditions were established to maximize the output parameter through the desirability function approach.

Influence of Processing Variables on Dynamic Mechanical Response of Laser-Sintered Glass-Filled Polyamide

For establishing selective laser sintering in manufacturing technology, a wide knowledge about the influence of processing variables on the quality of sintered part is mandatory. In this regard, this article addresses the influence of key process parameters (i.e., bed temperature, laser power, beam speed, hatch distance, hatch length) on the dynamic mechanical properties of laser-sintered glass-filled polyamide specimens to enhance their service life. A face-centered central composite design of response surface methodology was employed to gather data, and mathematical models were developed to investigate the effects and interactions of selected input processing variables on the different performance characteristics. Experiments revealed that dynamic mechanical properties reduced with decrease in bed temperature. This was due to nonuniform fusion of powder particles and increased porosity. Specimens fabricated at high energy density (ED) were strong, solid, and isotropic but become weak, porous, and anisotropic, as the ED decreased. Poor material integrity and weak interparticle bonding were the main reasons of low dynamic mechanical strength. In addition, microstructural analysis was also performed to examine the surface morphology of sintered specimens. Further, optimum working conditions for producing parts with maximum dynamic mechanical response were determined.

Investigating the Surface Roughness of SLS Fabricated Glass-Filled Polyamide Parts Using Response Surface Methodology

Selective laser sintering (SLS) is an additive manufacturing process, which has become popular for the production of full functional end-user parts as well as prototypes. Presently, many sectors particularly aerospace, automotive and biomedical are using 3D solid models (prototypes) for visualization, kinematic testing or to fulfil other functional demands. Therefore, SLS parts should have good surface quality (i.e. surface roughness) to fulfil the demands of these sectors. Surface roughness of the SLS fabricated parts relies on the various input process parameters. Hence, this study investigates the influence of key contributing factors (i.e. bed temperature, laser power, scan speed, scan spacing and scan length) on the surface roughness of glass-filled polyamide parts. Five factors, three-level, and face-centred central composite design of experiment were used to collect data, and response surface methodology was employed to investigate the effects and interactions of selected input process parameters. It has been found that scan spacing followed by laser power is the most significant factor, which contributes the most to improve surface roughness. Furthermore, the optimum values of different parameters were obtained and verified by conducting confirmation experiments.

Effect of corrosion on the strength of dental silver amalgam

ObjectivesTo characterize the effect of crevice corrosion on the strength of dental silver amalgam as determined by the Hertzian ‘ball on disc’ method, with a view to providing a test method for use in standards compliance testing. Materials & methodsSixteen dental silver amalgam products were tested using the ‘ball on disc’ protocol at 30d after setting at 37°C in air or immersed in artificial saliva at pH 6.2. The mixed materials were packed into a tapered steel disc mold (10mm diameter, 3mm thick) resting on a glass surface, slightly overfilled and carved level with a sharp edge, then ejected at ∼10min and placed immediately into an incubator at 37°C. For corrosion specimens, the disc was laid on a flat polystyrene surface, immersed in artificial saliva, to create a spontaneous crevice corrosion cell. Testing was in Hertzian mode, using a 20mm steel ball, with the specimen resting on a disc of glass-filled polyamide (E=10GPa) at a cross-head speed of 0.2mm/min on a universal testing machine (E3000, Instron). The load at first crack was recorded, as was the number of radial cracks produced. ResultsRadial cracking into 2–4 pieces, in a clinically relevant (non-explosive) mode was observed in all cases. On average, corrosion caused a decrease in load at failure of ∼10%, although the interaction with alloy (analysis of variance) was significant (P∼0.03) indicating variation between products. Comparison of the 30d dry (uncorroded) results with those at 24h obtained earlier showed that there was highly significant increase on average (P∼5×10−12), but again a significant variation between products (P∼5×10−6), the maximum effect being +22%. SignificanceThe ball-on-disc test provides a facile means of ascertaining the sensitivity of dental silver amalgam to corrosion under clinically relevant conditions, and is viable as a standards compliance test.