Ti-Nb alloys are potential candidates owing to their excellent mechanical properties and high corrosion resistance for bioactive implant applications compared to other metallic materials. The purpose ...of this work is to investigate the effect of the Nb amount on the microstructure, mechanical properties, corrosion behavior and hydroxyapatite (HA) formation ability of Ti-Nb alloys produced via powder injection molding. According to the phase/microstructure studies, including XRD analyses, optical microscope, and SEM imaging, all of the alloys are composed of α+β phases, and with the increment of Nb content, β phase stability increases. Also, it is observed that Nb content has significant effects on the mechanical properties of the considered alloys. While the hardness/Transverse rupture strength values of Ti-Nb alloys (303-340HV, 992-440 MPa) are higher than that of the titanium (269HV, 300 MPa), the elastic modulus is measured as lower than (100–115 GPa) that of the titanium (132–140 GPa). The increment of Nb content causes to decrease of the hardness, bending strength and elastic modulus of Ti-Nb alloys. Also, the addition of Nb contributed to the improvement of corrosion resistance and induced to increase of hydroxyapatite formation ability.
•Nb addition induced to increase of hydroxyapatite formation ability.•Nb addition to the Ti contributed to the improvement of corrosion resistance.•With the increment of Nb content, stability of the β phase increases.•Highest Transverse Rupture Strength value (992 MPa) was obtained from Ti16 Nb alloy.•Lowest Elastic Modulus value was achieved when alloying Ti with 28 % wt. Nb.
The objective of this study was to compare the physical and mechanical performance of poly(lactic acid) (PLA), acrylonitrile butadiene styrene (ABS), and nylon 6 fabricated using fused deposition ...modeling (FDM) and conventional injection molding. It is found that different processing methods did not affect the viscosity of the samples, and the percentage difference for the density measurement is less than 4%. Water absorption of FDM samples is approximately 108% higher compared to those fabricated using the injection molding. The results also revealed that the FDM method did not strongly affect the degree of crystallinity of ABS, but it increased the degree of crystallinity of PLA and nylon 6. The tensile strength, Young's modulus, elongation at break, and impact strength of FDM samples were approximately 48%, 50%, 48%, and 78%, lower compared with the injection molded samples. The results presented can provide a guide to manufacturing the final products using FDM with the desired performance.
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In recent years, a new and promising polymer processing technology known as water‐assisted injection molding (WAIM) has attracted attention not only for academic reasons but also for its industrial ...applications. WAIM technology provides a new way to fabricate hollow or other complicated products due to its faster cycling time and light weight. This paper aims to give an overview of the basic principles and applications of WAIM as well as the current research status in academia. The origin and development of WAIM technology are first described and then, their advantages and applications are given. This review focuses on the experimental trends of WAIM such as computer simulation, the effect of processing parameters on the WAIM samples, and the morphology as well as related WAIM–molded composites and polymer blends' work.
This review is intended to provide an overview of the current research status in water‐assisted injection molding (WAIM). The main objective is to review the current research of WAIM such as computer simulation, the effect of processing parameters on the water penetration length and residual wall thickness, morphology, and orientation as well as related WAIM–molded composites and polymer blends.
Si/SiC composite ceramics was produced by reaction sintering method in process of molten silicon infiltration into porous C/SiC preform fabricated by powder injection molding followed by impregnation ...with phenolic resin and carbonization. To optimize the ceramics densification process, effect of slurry composition, debinding conditions and the key parameters of all technological stages on the Si/SiC composite characteristics was studied. At the stage of molding the value of solid loading 87.5% was achieved using bimodal SiC powder and paraffin-based binder. It was found that the optimal conditions of fast thermal debinding correspond to the heating rate of 10 °C/min in air. The porous C/SiC ceramic preform carbonized at 1200 °C contained 4% of pyrolytic carbon and ∼25% of open pores. The bulk density of Si/SiC ceramics reached 3.04 g/cm3, silicon carbide content was 83–85 wt.% and residual porosity did not exceed 2%.
The integration of metal and injection-molded composite materials has the potential to achieve numerous benefits in the design of structural components. However, due to the nature of plastics and the ...plastic injection molding (PIM), it becomes difficult to conciliate structural performance and part quality criteria. To obtain an optimal balance between the criteria, it is necessary an efficient design approach that can handle even complex models present in the real-world. In this study, the design enhancement of a recycled carbon fiber-reinforced plastic
/
metal hybrid automotive structure is realized via a novel manufacturability-constrained optimization with focus on part quality and PIM suitability. Multilayer size optimization is carried out by referring thickness design guidelines (TDGs) in order to optimize material distribution with composite material properties considered. Thickness-dependent properties are correlated with design variables and updated at each iteration. Part quality indicators and functional criteria are adopted to evaluate the optimized structures. The design procedure is shown to be superior to standard optimization methods and efficiently enable a satisfactory balance between performance and part quality by considering major injection-molded part design constraints. Reduction in cycle time, injection pressure, and warpage by 27, 63, and 7% were achieved along with 4% mass reduction. Moreover, statistical analyses showed that TDGs have a strong correlation with mass and stiffness while wall thickness has major effects in part quality and suitability with a confidence level of 95%. The results contribute to the advancement of lightweight and high-quality structural components produced by fast-manufacturing processes in the auto industry.
The present work aims to compare two different injection moulding foaming technologies, the already known MuCell® process and the new emerged technology IQ Foam®, as well as the cell structure and ...mechanical behavior of the obtained components. Glass fiber reinforced-polypropylene (>PP GF<) was employed to produce rectangular plates at solid and foamed conditions by using MuCell® and IQ Foam® processes combined with the complementary Core Back expansion molding technology, and the material structure as well as the tensile, flexural and impact properties were studied.
A solid skin-foamed core structure was observed in the samples foamed by both techniques. The mechanical properties decreased gradually with the apparent density of the microcellular plates. By increasing the thickness of the part because of the expansion of the cavity with the Core Back technology, the apparent density decreased but the flexural stiffness was greatly enhanced. Foamed samples obtained by IQ Foam® technology exhibited thicker solid surface layers and lower cell density than that of the MuCell® ones, but consequently higher resistant area, and thus, slightly higher mechanical properties. The new IQ Foam® technology is able to produce foamed parts with properties comparable to that of the MuCell® process, offering additional benefits such as cost-effectiveness, easy to use and machine-independence.
Polylactide (PLA) is known as one of the most promising biopolymers as it is derived from renewable feedstock and can be biodegraded. During the last two decades, it moved more and more into the ...focus of scientific research and industrial use. It is even considered as a suitable replacement for standard petroleum-based polymers, such as polystyrene (PS), which can be found in a wide range of applications-amongst others in foams for packaging and insulation applications-but cause strong environmental issues. PLA has comparable mechanical properties to PS. However, the lack of melt strength is often referred to as a drawback for most foaming processes. One way to overcome this issue is the incorporation of chemical modifiers which can induce chain extension, branching, or cross-linking. As such, a wide variety of substances were studied in the literature. This work should give an overview of the most commonly used chemical modifiers and their effects on rheological, thermal, and foaming behavior. Therefore, this review article summarizes the research conducted on neat and chemically modified PLA foamed with the conventional foaming methods (i.e., batch foaming, foam extrusion, foam injection molding, and bead foaming).
This paper aims to introduce the concept of cloud manufacturing (CMfg) in the injection molding industry. The CMfg platform for injection molding enterprises is built to improve the sharing, ...circulation and integration of the injection molding resources. With the implementation of the Internet of Things technologies in the traditional injection molding shop, the real-time manufacturing information of resources can be accurately captured and the entire molding process becomes more visible and traceable. The virtual machining service of the injection molding machine is encapsulated as a cloud service that published into the platform for on-demand use. When task orders are published, through the presented task-driven proactive service discovery method, competent services can be quickly found. The custom-oriented evaluation method based on technique for order preference by similarity to ideal solution is designed to help the demanders to find satisfying services according to their customized criteria. Since the task orders arrive dynamically, after these orders are assigned to the specified machine, a real-time order dispatching mechanism is developed to provide an optimal scheduling plan for the cloud service. Finally, the proposed framework and methods are illustrated by a numerical simulation.
Titanium and its alloys are used in production of implants such as knee and hip prostheses due to their superior properties. Ti–Nb–Zr ternary alloys are preferred over other metallic implant ...materials due to the presence of non-toxic elements, high corrosion resistance, good biocompatibility, and proper mechanical properties. The aim of this work is to investigate the effect of zirconium addition on
α
→
β
phase transformation, microstructure, and mechanical behavior of Ti–16Nb alloy. In doing so, Ti–16Nb–
x
Zr (
x
: 0, 5, 10, 15 mass%) alloys are produced by powder injection molding, which offers advantages such as low cost, net shape, and easy production of complicated parts for implant fabrication. X-ray diffraction analysis and scanning electron microscope images showed that zirconium behaves as a
β
stabilizer and according to differential thermal analysis, and it decreases
α
to
β
transition temperature approximately 30 °C. It is also revealed that increasing zirconium content caused finer microstructure and hardness of the alloy was raised from 336 HV
0.5
to 412 HV
0.5
while elastic modulus remains approximately steady between 103 and 110 GPa. It is concluded that Ti–Nb–Zr alloys have been found to be a good alternative to known metallic implant materials.
Progress has been made in applying life cycle assessment (LCA) towards the injection molding of polymers. After reviewing the methodology utilized in existing literature, however, it was found that ...the use of life cycle inventory (LCI) data did not accurately account for the many factors within the injection molding process that effect overall energy consumption. More specifically, the LCI databases referenced contained averaged energy consumption measurements from different injection molding systems. The use of such measurements - derived from factors such as machine type, processing temperature, and cooling requirements - is inherently flawed as the many variations in the injection molding process cause different applications of the injection molding process to have highly varied energy requirements. As such, to accurately account for this variability, future life cycle analyses of the injection molding process will require the use of a system capable of integrating this variability into the environmental impact assessment of those processes. This is demonstrated by a focused analysis highlighting the inaccuracies in current LCA methodology with respect to energy consumption.
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•Review progress in applying life cycle analysis to injection molding applications.•Lack of life cycle inventory for various injection molding processes.•Processing conditions, machinery, and molding techniques vary significantly.•Models pairing lifecycle burdens of each injection molding application are needed.•Collaborating lifecycle and plastics engineering leads to a more holistic LCA model.
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