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This paper proposes an interpretation methodology for the effect of transient process data on quality of injection molded parts. The transient process data measured in the actual processing space have been regarded as the most relevant information to manufacturing processes and product quality. However, its interpretation to pinpoint which feature in the data would affect part quality has traditionally relied on knowledge and understanding of the manufacturing process. The main objective of this method is to reduce the dependency of the transient process data analysis on process knowledge and understanding by using explainable artificial intelligence (XAI). The contribution of the 'section-wise' features in the transient process data to the quality prediction of machine learning (ML) models was investigated for the first time. The interpretation results of the effect of cavity pressure and mold surface temperature on four different quality factors represented reasonable explanations of the characteristics of the polymer materials, product geometry, and molding process. Due to the intermediate relationship of the transient process data with the user-specified process parameters and the resulting quality variables, the interpretation results can be further utilized to optimize the process and provide the optimal transient process data profile for best part quality. [ABSTRACT FROM AUTHOR]

Increased recycling of plastics is an essential step toward a more sustainable use of materials, where some of the most challenging fractions are engineering materials and composites. Used pump houses prepared from glass fiber (GF)‐reinforced blends of polyphenylene oxide (PPO) and high‐impact polystyrene (HIPS) obtained through a take‐back scheme (take‐back, TB) were characterized and shredded for use in the preparation of new composites by injection molding. Initial degradation was observed on the surface of the TB parts; however, the core of the material was unaffected. Mechanical reprocessing of regrind and virgin material showed a reduction of tensile strength already at 10% regrind, which was attributed to fiber length reduction during reprocessing. At the same time, Young's modulus and extension at break were largely unaffected, confirming that 25% of TB could be included without any additional loss of properties. As a worst‐case scenario, tests with extensively degraded material showed that Young's modulus and tensile strength would ultimately be reduced with an increasing amount of heavily degraded material and that a balance would have to be found between loss of properties and recycled content for heavily degraded material. [ABSTRACT FROM AUTHOR]

Injection molding is widely used to produce various components and products. An attempt to achieve a certain quality necessitates sacrificing other qualities and consuming excessive energy, causing significant carbon emissions. Although many studies have been conducted on optimizing injection molding parameters, they typically focus on optimizing a single quality attribute. Multi-objective optimization is the solution to address all relevant qualities and energy consumption simultaneously. Taguchi analysis can achieve single-objective optimization with fewer experiments and simple calculations. It provides an efficient way to optimize specific quality attributes. In contrast, response surface methodology (RSM) explores and optimizes the complex relationships within multivariable systems. RSM establishes a mathematical model for optimizing multivariable systems. However, RSM requires more experiments and involves more complex calculations. Single-variable experiments and Taguchi analysis were first used to address energy consumption and identify the key factors. This study focused on plastic screws, aiming not only to explore energy consumption but also to optimize the quality in terms of diameter, weight, and tensile strength. To construct mathematical models, this study applied Taguchi analysis and RSM. Using the desirability function, the RSM model was optimized, and the applicability of both approaches in multi-objective optimization for balancing energy efficiency and product quality was evaluated. The research results indicate that holding and cooling time significantly impact energy consumption. Both the Taguchi method and RSM optimization results show that the optimal combination is a melt temperature of 230 °C, holding pressure of 40 MPa, holding time of 3 s, and cooling time of 3 s. This optimal combination can reduce energy consumption by 29 ~ 33% while maintaining a certain level of product quality. However, compared to the Taguchi method, which relies on subjective judgment to select the optimal conditions, RSM can achieve more precise and reliable optimization results through regression analysis and model evaluation. [ABSTRACT FROM AUTHOR]

In this study, a novel biodegradable coir fiber (CF) reinforced thermoplastic starch (TPS) and poly(butylene adipate‐co‐terephthalate) (PBAT) composites (CF/TPS/PBAT) with a constant TPS: PBAT weight ratio of 70:30 and 5, 10, 15, and 20 wt% additions of CF were prepared by the melt blending and injection molding. The effects of fiber content and fiber surface modification on the mechanical and thermal properties of the prepared biocomposites were investigated. The incorporation of fibers effectively enhanced the mechanical and thermal properties of TPS/PBAT blends. Due to the removal of hemicellulose and impurities on the fiber surface after alkali treatment, the interfacial adhesion of the fiber was enhanced, thus improving the compatibility between the fibers and the matrix. At 20 wt% CFs with alkali treatment, the tensile strength exhibited 393% improvement and flexural strength exhibited 536% improvement over TPS/PBAT blends. Thermal analysis showed that the thermal stability, storage modulus, and glass transition temperature of the composites increased with the increase of fiber content. This work is significant for the development of biodegradable materials. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to evaluate the effectiveness of two different viscosities of short fiber-reinforced composite resin (SFRC) cores and two different viscosities of veneering composite resins on the fracture strength of direct occlusal veneers. Materials and methods: One maxillary premolar was virtually prepared for an occlusal veneer and printed into resin dies. In total, (n = 48) resin dies were printed and assigned into three groups according to the type of core material of the occlusal veneer; mono-structured without a SFRC core, a high viscosity SFRC core, and a low viscosity SFRC core. Each group was re-divided into two subgroups (n = 8) according to the veneering composite resin; packable composite resin and injectable composite resin. Mono-structured and bi-structured direct occlusal veneers were fabricated on the resin dies using the mentioned core and veneering materials with the occlusal replica technique. Fracture strength was evaluated using a universal testing machine and the mode of failure was inspected. Statistical analysis to compare the core and veneering materials was performed using independent t test (P ≤ 0.05) and one-way ANOVA followed by tukey’s post hoc test (Pa ≤ 0.0166) when appropriate. Interactions between subgroups were tested using two-way ANOVA, and one-way ANOVA was used to compare all subgroups followed by tukey’s post hoc test (Pa ≤ 0.0033). Intergroup comparison between failure modes were performed using chi square test (Pa ≤ 0.0033). Results: The presence of a SFRC core significantly improved the fracture strength of the specimens. There was no significant difference between the fracture strength of high viscosity SFRC and low viscosity SFRC cores. Specimens veneered with injectable composite resin had significantly superior fracture strength compared to packable composite resin. Additionally, there was a weak correlation between fracture strength and mode of failure. Conclusion: Short fiber reinforced composite resin significantly increases the fracture strength of direct occlusal veneers. Injectable composite resin has significantly higher fracture strength than packable composite resin as veneering materials of direct occlusal veneers. Clinical relevance: Bi-structured direct occlusal veneers fabricated of injectable composite resin with low viscosity SFRC cores can withstand high masticatory forces in stress-bearing areas. [ABSTRACT FROM AUTHOR]

Polymeric materials are inexpensive, lightweight, and easy to process. With injection molding technology, they can be used to mass-produce complex geometric products. Although virtual quality measurement systems can prevent product defects, they may not be effective for recycled polymers. Recycling is necessary to achieve sustainable production, but the recycling process can greatly affect material properties. Accordingly, we propose using transfer learning (TL) to apply quality models for virgin materials to recycled materials. Key features from cavity pressure sensor information were extracted as quality indices, and a neural network was trained to predict the part weight and geometric dimensions. TL was then used to fine-tune this pretrained model on data for recycled materials. This method requires little data collection and could greatly reduce the cost of improving quality when using recycled materials. For all quality metrics, the TL model achieved superior performance to a conventional model, even when applied to a 40% smaller dataset; it also converged more quickly and in fewer iterations. A comprehensive analysis indicated that the model had a favorable fit. These results confirm that TL is effective in predicting the quality of injection molding products made with recycled materials; it has superior predictive accuracy and requires less training time than conventional methods. The described process could reduce the cost of implementing process quality inspection systems, incentivizing the use of recycled materials. [ABSTRACT FROM AUTHOR]

Injection molding is a pivotal industrial process renowned for its high production speed, efficiency, and automation. Controlling the motion speed of injection molding machines is a crucial factor that influences production processes, directly affecting product quality and efficiency. This paper aims to tackle the challenge of achieving optimal tracking control of injection speed in a standard class of injection molding machines (IMMs) characterized by nonlinear dynamics. To achieve this goal, we propose a learning-based model predictive control (LMPC) scheme that incorporates Gaussian process regression (GPR) to predict and model uncertainty in the injection molding process (IMP). Specifically, the scheme formulates a nonlinear tracking control problem for injection speed, utilizing a GPR-based learning residual model to capture uncertainty and provide accurate predictions. It learns the dynamics model and historical data of the IMM, automatically adjusting the injection speed according to target requirements for optimal production control. Additionally, the optimization problem is efficiently solved using a control-constrained differential dynamic programming approach. Finally, we conduct comprehensive numerical experiments to demonstrate the effectiveness and efficiency of the proposed LMPC scheme for controlling injection speed in IMP. [ABSTRACT FROM AUTHOR]

This study aims to investigate the recycling of end‐of‐life computer plastics, focusing on polycarbonate (PC) and acrylonitrile–butadiene–styrene (ABS) copolymer, which constitute a significant portion of collected computers. Through differential scanning calorimetry and infrared spectroscopy analyses, the properties of raw PC, ABS and poly(methyl methacrylate) (PMMA) were evaluated. Various blends of PC and ABS were prepared, incorporating different percentages of recycled PMMA as a cost‐effective coupling agent. These blends were processed through melt compounding using a contra‐rotating twin‐screw extruder and subsequently shaped by injection molding. An experimental mixture design was applied to evaluate the mechanical and physical properties of the composite materials, including melt flow index, hardness, flexural strain at break and Charpy impact strength. The results of the desirability analysis indicated that the optimal blend for achieving a balance between mechanical and physical properties consists of a high PC content (approximately 80% or more), a low ABS content (less than 20%) and less than 5% recycled PMMA. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In recent years, a significant increase in the development of new composite materials with desirable mechanical, thermal or surface properties has been observed. One of the popular polymers on the market is polylactide. This article explores how to modify the polymer using steel fibres and organosilicon compounds (SSQ-SH, SSQ-SH-OCT, and SSQ-SH-OFP) to enhance its properties. Test samples were obtained by injection molding with varying concentrations of 0.5%, 1%, 1.5%, 2.5%, and 5% of steel fibres. Mechanical tests, including tensile strength, elongation at break, and impact strength, were conducted, along with an analysis of the contact angle. The modified samples showed higher impact strength values, with the PLA /steel fibres /SSQ-SH sample seeing an increase of 12%. The addition of modifiers with fluoroalkyl groups led to a contact angle increase of 8.5% compared to neat PLA. Thermal tests (TGA) were also carried out to determine the influence of fibres and organosilicon compounds on decomposition. [ABSTRACT FROM AUTHOR]

After certain time of operation, the cross-section of cooling channels in injection molds may decrease due to fouling, i.e. the formation and growth of a layer of sediment on the walls of the channels. This phenomenon can decrease heat transfer or ultimately completely block the flow of coolant in the channel. The build-up of the sediment layer increases the temperature of the mold, which may consequently reduce the quality of the plastic products. In the paper, the pressure drop in a typical cooling channel of an injection mold is investigated, as well as the effect of the sediment layer on the coolant flow in an example channel with a diameter of 10 mm. A novelty is the developed analytical model that allows determining the pressure drop in the case when two perpendicular channels do not intersect centrally due to manufacturing inaccuracies that often happen when drilling long channels in hard materials. The proposed hydraulic model allows for calculation of the coolant pressure drop in real injection molds and can be an alternative to time-consuming CFD simulations. The presented results of measurements and the hydraulic model calculations show that the thickness of the sediment layer in the tested channel of the actual injection mold can be up to 1.7 mm. The hydraulic model proposed in this work allows for the estimation of the thickness of the sediment layer and the identification of places of local increase in the coolant velocity, where self-cleaning of the channels in injection molds may take place. [ABSTRACT FROM AUTHOR]

The effect of polyphenylene sulfide binder content on the properties of injection molding polyphenylene sulfide/NdFeB magnets were investigated. The maximum filling amount of NdFeB magnetic powder was 87.6 wt.‐%, and the mixing process and subsequent injection molding of the polyphenylene sulfide/NdFeB were in good condition. The melt mass‐flow rate of the polyphenylene sulfide/NdFeB granular materials reached 121.7 g/10 min, the compressive strength of the polyphenylene sulfide/NdFeB magnet was 92.18 MPa, and its maximum magnetic energy product reached 5.59 MGOe. The structure and morphology characteristics of polyphenylene sulfide/NdFeB magnets were investigated using scanning electron microscopy and atomic force microscopy. The corrosion behavior of polyphenylene sulfide/NdFeB magnets was also studied using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results indicated that the injection molding process facilitated the uniform coating of polyphenylene sulfide particles on NdFeB powder, which directly enhanced the corrosion resistance of polyphenylene sulfide/NdFeB magnets. With an increase in polyphenylene sulfide content, the surface of polyphenylene sulfide/NdFeB magnets became more uniform. The corrosion current density of 13 wt.‐% polyphenylene sulfide/NdFeB magnet was approximately one order of magnitude lower than that of 9 wt.‐% polyphenylene sulfide/NdFeB magnet, indicating an improved corrosion resistance of polyphenylene sulfide/NdFeB magnet. [ABSTRACT FROM AUTHOR]

Highlights This study explores the mechanical, thermal, and morphological behavior of polylactic acid (PLA) composites reinforced with flax fiber (FF) during recycling. The influence of the addition of bio‐filler (w/w) on the recycling of FF/PLA composites was also analyzed. The recycling influencing the performance of FF/PLA composite was compared with that of halloysite nanotube (HNT)/FF‐PLA composites. The FF/PLA and HNT/FF‐PLA composited were fabricated by injection molding subjected to multiple recycling. The tensile and flexural properties of both composites were assessed after each recycling. Fractured specimens of the recycled samples were analyzed using a scanning electron microscope to study their morphology. Thermal degradation was evaluated through thermogravimetric analysis of the recycled FF/PLA and HNT/FF‐PLA samples. After the fifth recycling process, the HNT/FF‐PLA composite experienced a decrease in tensile strength by 75.01% and flexural strength by 59.88%. The performance of FF/PLA and HNT/FF‐PLA composites was detrimentally affected due to the thermal deterioration of flax fiber and the subsequent decrease in fiber length resulting from repeated reprocessing. The highest degradation for non‐recycled FF/PLA and HNT/FF‐PLA samples occurred at temperatures of 354°C and 347°C, respectively. Whereas the maximum degradation for recycled cellulose (RC)‐5 (fifth recycled) FF/PLA and HNT/FF‐PLA composite occurred at 328 and 327°C. Adding 1% HNT increased the tensile and flexural strength by 12.5% and 1.79%. The behavior of the composites was affected by the thermal degradation of FF. The maximum degradation of RC‐5 FF/PLA composite occurred at 327°C. The maximum degradation for RC‐5 HNT/FF‐PLA composite was noticed at 328°C. [ABSTRACT FROM AUTHOR]

The depletion of conventional materials and their adverse environmental impacts have prompted a shift toward sustainable alternatives in composite materials engineering. In pursuit of this objective, this study investigated the mechanical properties of polypropylene matrix composites reinforced with Cordenka, an artificial cellulose fiber, and compared them to those reinforced with ramie, a natural cellulose fiber. Continuous strand composites were developed using the Multi-Pin-assisted Resin Infiltration (M-PaRI) process. The strands were subsequently sectioned into 15 mm lengths and injection-molded into dumbbell and strip specimens for mechanical characterization. The results showed that 20 wt% Cordenka/PP composites exhibited a tensile strength of 68.7 MPa, 2.04 times higher than neat PP and 1.66 times greater than the 20 wt% ramie/PP composites. Impact testing further demonstrated that Cordenka/PP composites absorbed 2 to 2.5 times more impact energy than ramie/PP composites, regardless of the presence of notches. Fiber length analysis indicated that Cordenka fibers maintained their length beyond the critical fiber length, allowing for efficient stress transfer and acting as a more effective reinforcement compared to ramie fibers, which were below this threshold. Consequently, the Cordenka/PP composites exhibited significantly enhanced mechanical performance. Scanning electron microscopy (SEM) analysis revealed fewer fiber pullouts in ramie-reinforced composites, suggesting superior interfacial adhesion to the PP matrix, although it did not translate to higher mechanical properties. These findings underscore the potential of Cordenka as a sustainable alternative to synthetic, non-biodegradable fibers in PP composites, providing improved mechanical properties and promising prospects for advanced composite applications. [ABSTRACT FROM AUTHOR]

With the development of new energy vehicles, there is a growing demand for automotive interior materials that meet higher standards. In this case, thermoplastic elastomer (TPE), being a completely recyclable environment‐friendly polymer material, possesses advantages such as plasticizers and solvents free, excellent mechanical properties, less volatile organic compounds (VOC) release and low processing cost compared with polyvinyl chloride (PVC), polyurethane (PU), and thermoplastic polyolefin (TPO) skins, become a desirable choice for automotive injection molding automotive skin. Hence, this work investigates the influence of hydrogenated styrene‐butadiene‐styrene block copolymer (SEBS) molecular weight, chemical structure, and polypropylene (PP) doping amount on thermodynamic, crystallinity, rheological, and mechanical properties of TPE, which provides a scientific basis for guiding the material selection of TPE injection molding skin. [ABSTRACT FROM AUTHOR]

Injection molding is a widely utilized manufacturing process across various industries. The cooling time in injection molding is an important factor that affects the productivity and energy consumption of the process. The production efficiency is directly proportional to the cooling efficiency, yet optimizing this cooling process presents significant challenges. The fixed cooling parameters are not suitable for all types of material, thus increasing the molding deviation. To address these challenges, this research work proposed a Regularized with Mish Linear Unit-based Deep Learning Neural Network-based material prediction with optimization of derived variables using the Banana Function-centric Green Anaconda Optimization approach. Initially, the features are extracted from the raw materials, and then the material type is predicted by using Regularized with Mish Linear Unit-based Deep Learning Neural Network. Conversely, various machine properties are clustered utilizing the binomial distribution with damping factor-based farthest first clustering methodology. Subsequently, parameters are derived from both the predicted material and the clustered machine property. The pressure of the machine is controlled by a quasi-conservative with an optimized proportional integral derivative controller. Then, the optimal parameters are selected from the Banana Function-centric Green Anaconda Optimization algorithm. In the optimal parameter selection, the multi-objective is considered by minimization of temperature, cooling time, pressure drop, and power consumption. In experimental analysis, the performance of the proposed approach is analyzed with the existing approaches. The proposed approach attains 98.9% accuracy, which is higher than existing approaches. [ABSTRACT FROM AUTHOR]

This study investigates the joining of dissimilar materials, specifically galvannealed advanced high‐strength steel (AHSS) and glass fiber‐reinforced polyamide 6 (PA 6) to achieve lightweight automotive. AHSS and PA 6 are widely used in the automobile industry; however, a direct joining of those two materials is difficult owing to their great difference in physical properties. Therefore, laser surface texturing (LST) and plastic injection molding are adopted to join AHSS and PA 6, which can create a strong mechanical interlock between AHSS and PA 6, resulting in an excellent joint strength compared to other joining techniques. The effects of LST parameters (groove depth and hatch distance) and injection molding temperatures on the joint strength are examined. The maximum AHSS‐PA 6 joint strength is measured at 72.3 MPa. Additionally, the microstructure and mechanical properties of recast, which develops over the original metal surface by melting and resolidifying, are analyzed. Compared to the base metal, the recasts exhibit higher hardness due to smaller grain sizes. PA 6 fills the laser‐textured grooves and spaces between the recasts, acting as a mechanical interlock that enhances joint strength under tensile shear testing. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive analysis of the effects of incorporating low levels of cellulose nanofibrils (CNFs) into an acrylonitrile butadiene styrene (ABS) matrix on the properties of ABS composites. Five samples with varying CNF content (0.125%, 0.25%, 0.5%, and 1%) were prepared, alongside a pure ABS sample for comparison. The preparation involved mechanical blending, followed by extrusion and injection molding. Mechanical, thermal, water absorption, surface gloss, and microstructural properties of the composites were characterized. Tensile and three-point bending tests revealed that the addition of CNFs improved both stiffness and strength, with the highest tensile modulus observed in ABS/NC4 (1% CNFs) and the highest flexural strength in ABS/NC1 (0.125% CNFs). Impact resistance, evaluated through Charpy impact testing, showed enhancement up to 0.5% CNF content, beyond which a decline was observed due to increased particle quantity. Thermal properties exhibited negligible changes, with slight variations in glass transition and melting temperatures observed within a narrow range. SEM analysis confirmed a uniform distribution of CNFs, contributing to enhanced crack resistance, although higher CNF content led to increased void formation. Surface gloss measurements indicated smoother material surfaces with higher CNF content. The study concludes that integrating CNFs into ABS composites improves mechanical properties and impact resistance, necessitating careful consideration of CNF content for optimal performance. Further refinement could tailor ABS/CNF composites for specific applications. [ABSTRACT FROM AUTHOR]

The design of composite I‐sections in aerostructures faces a significant challenge with conventional laminates because they are prone to delamination under out‐of‐plane loads. To address this issue, this study investigates the design, manufacture, and mechanical properties of 3D woven near‐net‐shaped composite I‐sections. The study also compares their advantages with equivalent laminates and examines the influence of weave patterns on their mechanical behavior. Specimens were manufactured using the vacuum‐assisted resin transfer molding technique, and quasi‐static tensile, compressive, and bending tests were conducted to assess the properties of I‐sections with three different weave patterns. It finds that the ultimate strength and damage tolerance of the considered design of 3D woven I‐sections are better than the considered design of 2D woven laminated counterparts, and different weave patterns play a significant effect in damage mode and load‐bearing capacity. In addition, using 3D woven preforms to manufacture composite I‐sections also exhibits shortened production time in terms of layup and resin infusion. Highlights: The 3D woven I‐sections show improved damage tolerance over 2D counterparts.The design of weave patterns affects the properties of I‐section composites.Using 3D preforms to manufacture I‐sections exhibits shortened production time.Design consideration is proposed for the optimal weave pattern of the I‐sections. [ABSTRACT FROM AUTHOR]

Polyamide 6 (PA6) thermoplastic‐based composites are often used in automobile, aerospace, marine, and biomedical applications. Here, PA6 and its composites with varied chopped glass fiber (GF) concentrations of 5, 10, and 20 mass% were fabricated by injection molding. The specimens were characterized by structural, thermal kinetic, mechanical, as well as tribological analyses. Tribological performance was evaluated in dry pin‐on‐disc test apparatus with three different levels of time, speed, and load factors. The PA6/GF composites showed high decomposition activation energy compared to pure PA6. Thermal activation, Ea increased to 46.16% with increasing of GF content up to 10 mass% in the composites compared to PA6. PA6/5GF exhibited best mechanical properties (e.g., strength = 44.46 MPa and Hardness = 45.2). Addition of GF in PA6 significantly improved tribological properties, coefficient of friction (COF) and specific wear rate (WR) besides thermal stability and mechanical properties of the composites. Especially, COF and WR of PA6/5GF composite decreased by 17%–65% and 68%–92%, respectively, compared to PA6. ANOVA statistical results determined the significant contribution of the tribological factors to the performance metrics of the composites for COF and WR. Therefore, the PA6/5GF composite would highly be useful for tie‐rod gears and bearings as a crucial structural component in automotive bodywork. [ABSTRACT FROM AUTHOR]

Modern polymer‐based technical components not only have to fulfill demanding mechanical‐structural properties but need to integrate different functions to yield hybrid systems for complex operations. Typically, neither materials nor processing technologies are fully compatible with each other. The aim of the work is to combine the advantages of seemingly incompatible manufacturing processes such as high‐volume injection molding (IM) and precision additive manufacturing to produce functional and customized hybrid materials. IM is widely used for polymer processing but stands against high investment costs for tailor‐made molds with high‐resolution features. They focus on overprinting of injection‐molded parts made of thermoplastic polyurethane (TPU) with microstructures via projection‐microstereolithography (PµSL) to generate hybrid polymer materials with spatially tailored stiffness, enabling selective reinforcement, resulting in an E modulus increase of 195% compared to mere IM‐processed TPU. With that, the hybridization of processing methods is showcased to extend the product properties of polymer materials obtained via either IM or PµSL printing that have, prospectively, a maximum degree of individualization as well as a multitude of structural and functional features at the same time. To achieve optimum interfacial adhesion, the influence of surface roughness is studied, and reinforcement effects of different overprinted microstructure types are evaluated. [ABSTRACT FROM AUTHOR]

The increasing demand for sustainable materials in high-value applications, particularly in the automotive industry, has prompted the development of biocomposites based on renewable or recyclable matrices and natural fibers as reinforcements. In this context, this paper aimed to produce composites with improved mechanical and thermal properties (tensile, flexural, and heat deflection temperature) through an optimized process pathway using a biobased polyamide reinforced with short basalt fibers. This study emphasizes the critical impact of fiber length, matrix adhesion, and the variation in matrix properties with increasing fiber content. These factors influence the properties of short-fiber composites produced via primary processing using extrusion and shaped through injection molding. The aim of this work was to optimize extrusion conditions using a 1D simulation software to minimize excessive fiber fragmentation during the extrusion process. The predictive model's capacity to forecast fiber degradation and the extent of additional fiber breakage during extrusion was evaluated. Furthermore, the impact of injection molding on these conditions was investigated. Moreover, a comprehensive thermomechanical characterization of the composites, comprising 10%, 20%, and 30% fiber content, was carried out, focusing on the correlation with morphology and processing using SEM and micro-CT analyses. In particular, how the extrusion process parameters adopted can influence fiber breakage and how injection molding can influence the fiber orientation were investigated, highlighting their influence in determining the final mechanical properties of short fiber composites. By optimizing the process parameters, an increment with respect to bio-PA11 in the tensile strength of 38%, stiffness of 140%, and HDT of 77% compared to the matrix were obtained. [ABSTRACT FROM AUTHOR]

Electrical erosion molding (EDM) is an unconventional machining technology widely used in the manufacture of injection molds for plastics injection molding for the creation of complex cavities and geometries. However, EDM productivity can be challenging, directly influencing mold manufacturing time and cost. This work aims to improve EDM productivity in the context of mold manufacturing for plastics injection molding. The research focuses on the optimization of processing parameters and strategies to reduce manufacturing time and increase process efficiency. Through a rigorous experimental approach, this work demonstrates that the optimization of EDM parameters and strategies can lead to significant productivity gains in the manufacture of plastic injection molds without compromising part quality and accuracy. This research involved a series of controlled experiments on a Mitsubishi EA28V Advance die-sinking EDM machine. Different combinations of pre-cutting parameters and processing strategies were investigated using copper electrodes on a heat-treated steel plate. Productivity was evaluated by measuring the volume of material removed, and geometrical accuracy was checked on a coordinate measuring machine. The experimental results showed a significant increase in productivity (up to 61%) by using the "processing speed priority" function of the EDM machine, with minimal impact on geometric accuracy. Furthermore, the optimized parameters led to an average reduction of 12% in dimensional deviations, indicating improved geometric accuracy of the machined parts. This paper also provides practical recommendations on the selection of optimal EDM processing parameters and strategies, depending on the specific requirements of plastic injection mold manufacturing. [ABSTRACT FROM AUTHOR]

Nowadays, plastic contamination worldwide is a concerning reality that can be addressed with appropriate society education as well as looking for innovative polymeric alternatives based on the reuse of waste and recycling with a circular economy point of view, thus taking into consideration that a future world without plastic is quite impossible to conceive. In this regard, in this review, we focus on sustainable polymeric materials, biodegradable and bio-based polymers, additives, and micro/nanoparticles to be used to obtain new environmentally friendly polymeric-based materials. Although biodegradable polymers possess poorer overall properties than traditional ones, they have gained a huge interest in many industrial sectors due to their inherent biodegradability in natural environments. Therefore, several strategies have been proposed to improve their properties and extend their industrial applications. Blending strategies, as well as the development of composites and nanocomposites, have shown promising perspectives for improving their performances, emphasizing biopolymeric blend formulations and bio-based micro and nanoparticles to produce fully sustainable polymeric-based materials. The Review also summarizes recent developments in polymeric blends, composites, and nanocomposite plasticization, with a particular focus on naturally derived plasticizers and their chemical modifications to increase their compatibility with the polymeric matrices. The current state of the art of the most important bio-based and biodegradable polymers is also reviewed, mainly focusing on their synthesis and processing methods scalable to the industrial sector, such as melt and solution blending approaches like melt-extrusion, injection molding, film forming as well as solution electrospinning, among others, without neglecting their degradation processes. [ABSTRACT FROM AUTHOR]

This article deals with the impact of short glass fiber (GF) on the performance of 60/40 wt% of polyamide 6/polyamide 12 (PA6/PA12) blend. The short fiber-reinforced composites were fabricated by using melt compounding via twin screw extruder and injection molding. The morphological, water uptake, rheological, thermo-mechanical, and mechanical properties of the composites were discussed. The morphological observations show that the PA6/PA12 blend exhibited compatible morphology and also adhesion between the fiber and matrix was quite strong. The tensile strength/modulus and storage modulus of the blend were substantially improved with GF reinforcement as a result of these morphological findings. While the water uptake of neat PA6 decreased significantly after blending with PA12, the incorporation of GF further reduced the water uptake of the PA6/PA12 blend. The thermomechanical analysis showed the enhancement of the stiffness of the composites and also glass transition temperature increment. [ABSTRACT FROM AUTHOR]

Multicomponent injection molding industry is experiencing a growth due to its ability to reduce production costs and streamline processes. However, compared to single injection, multicomponent injection molding introduces interface regions where multiple engineering polymers meet. Consequently, it is essential to comprehend and enhance the adhesive bonding strength properties of these polymers. This study investigates the adhesive bond strength of polymer-polymer multimaterial molding using two-shot bi-injection and overmolding techniques. The research also emphasizes the influence of injection molding process parameters of mold temperature and melt temperature on the adhesive bond strength of polycarbonate (PC), polycarbonate-acrylonitrile butadiene styrene (PC-ABS), acrylonitrile butadiene styrene (ABS), and styrene ethylene butadiene styrene (SEBS). Tensile strength results revealed that the bi-injection method yields the highest interface strength, approximately 10 MPa lower than the reference value for single-material hard-hard plastics. Results from overmolded samples for both injection sequences are presented, indicating that material with low melting temperature was found to be the first injected part for better adhesion strength. Empirical equations for estimating adhesion strength were derived as a function of interface temperature obtained from CAE numerical simulations and polymer glass transition temperatures. The proposed equation achieved R2 values greater than 0.96. This empirically derived equation will serve as a guide for multi-injection manufacturing processes. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to enhance merging of additive manufacturing (AM) techniques with powder injection molding (PIM). In this way, the prototypes could be 3D-printed and mass production implemented using PIM. Thus, the surface properties and mechanical performance of parts produced using powder/polymer binder feedstocks [material extrusion (MEX) and PIM] were investigated and compared with powder manufacturing based on direct metal laser sintering (DMLS). Design/methodology/approach: PIM parts were manufactured from 17-4PH stainless steel PIM-quality powder and powder intended for powder bed fusion compounded with a recently developed environmentally benign binder. Rheological data obtained at the relevant temperatures were used to set up the process parameters of injection molding. The tensile and yield strengths as well as the strain at break were determined for PIM sintered parts and compared to those produced using MEX and DMLS. Surface properties were evaluated through a 3D scanner and analyzed with advanced statistical tools. Findings: Advanced statistical analyses of the surface properties showed the proximity between the surfaces created via PIM and MEX. The tensile and yield strengths, as well as the strain at break, suggested that DMLS provides sintered samples with the highest strength and ductility; however, PIM parts made from environmentally benign feedstock may successfully compete with this manufacturing route. Originality/value: This study addresses the issues connected to the merging of two environmentally efficient processing routes. The literature survey included has shown that there is so far no study comparing AM and PIM techniques systematically on the fixed part shape and dimensions using advanced statistical tools to derive the proximity of the investigated processing routes. [ABSTRACT FROM AUTHOR]

The objective of the experimental analysis was to assess the impact of the reuse of technological waste (recyclate) on the selected performance properties of the fibrous polymer composite used to produce components for the automotive industry by injection molding technology. Polyphthalamide (PPA), which belongs to a group of high-tech polymers, was chosen as the analyzed material. In accordance with the set goals, the rheological, mechanical, and structural properties of the material were evaluated using ANOVA analysis in the experimental part of the work, depending on the mass ratio of the recycled material added to the virgin material. The influence of the proportion of recycled material on the lifetime of moldings by the method of their exposure at an elevated temperature for a defined time was also assessed. During the research, it was found that at a concentration of up to 40 wt. % of recyclate, its mechanical properties do not change significantly. At a concentration of 50 wt. %, there is a rapid decrease in mechanical properties. In the long term, it can also be said that the addition of recyclate significantly affects the service life of the components. No significant changes in morphology were observed during the analysis of structural properties. [ABSTRACT FROM AUTHOR]

This study explores the use of vat polymerization stereolithography (SLA) for fabricating mold tooling, subsequently utilized in injection molding (IM) and overmolding of tensile specimens and directly compared to those produced using metal molds. The results first find the manufacturing time for an SLA‐fabricated mold is remarkably short, approximately 6 h, presenting a substantial improvement over traditional methods. Mechanical testing revealed that the tensile specimens from the SLA‐fabricated molds exhibited the highest tensile strength among all overmolding batches. This performance was consistent with the tensile bars produced using metal molds, demonstrating the viability of SLA‐fabricated molds for overmolding applications and highlighting the potential of FDM to customize the properties of final products. However, variations in mold types impacted the dimensional tolerance and tensile strength of the final specimens. Metal mold‐fabricated tensile bars exhibited superior dimensional accuracy and maximum tensile strength (50.6–61.7 MPa) compared to those produced with SLA‐fabricated molds (46.9–55.9 MPa). These differences are attributed to the rougher surface finish inherent to the layer‐by‐layer construction of SLA and the internal stresses and defects resulting from lower thermal conductivity and uneven cooling. In conclusion, this study underscores the promising future applications of SLA‐fabricated molds in overmolding, offering reduced manufacturing costs and enhanced design freedom. The findings support the potential of SLA to revolutionize mold fabrication, thereby extending its utility and optimizing the production of polymer components with customized properties. Highlights: SLA molds compared to metal molds for direct injection molding and overmolding.FFF preforms with varied geometries were overmolded to finalize the specimens.Joint configurations in overmolding improved tensile performance.Overmolding showed better dimensional accuracy than FFF specimens.SLA mold preparation significantly reduced manufacturing costs. [ABSTRACT FROM AUTHOR]

In a multi‐cavity mold, parts from each cavity have consistent properties if the runner system ensures balanced melt‐front advancement. An unbalanced mold, however, narrows the processing window, complicating quality control and making it harder to maintain standards. Molds with an inherently balanced filling, such as the H‐type runner system, are preferred. However, as the number of cavities increases, improvements are needed to address the issues caused by shear heating. Additionally, the material waste in the H‐type runner system is significantly greater than in the fishbone runner system. Based on the rheological concept, a two‐stage analytical approach is established to optimize the fishbone runner system. The diameter of each runner in the fishbone runner system is optimized by controlling pressure drop and remaining time to achieve balanced filling. The impact of these factors is thoroughly examined, as well as why they must be controlled during optimization. The proposed work links the physical situation to its mathematical model, proving highly beneficial for new runner system designs, especially without commercial software assistance. Highlights: A new approach to solving unbalanced filling in multi‐cavity molds.Pressure drop and remaining time are key factors for optimization.Two‐stage analytical approach ensures optimization accuracy.The optimal runner system reduces injection pressure for molding.An alternative method for designing fishbone runners without CAE assistance. [ABSTRACT FROM AUTHOR]

Biodegradable polymers, particularly Polyhydroxyalkanoates (PHAs) and their derivatives, have garnered increasing attention across diverse industries owing to their distinct advantages such as bio-based sourcing, biocompatibility, and impressive biodegradability performance. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is one of the most attractive members of PHAs with a great potential to replace conventional non-biodegradable polymers. However, one critical drawback restricting PHBV usage is its thermal instability, which could bring about a narrow processing window, especially for conventional melt processing methods such as injection molding. Moreover, the high crystallinity and slow nucleation rate make PHBV brittle, leading to poor mechanical performance. This study incorporated epoxidized natural rubbers (ENR-25 and ENR-50) into PHBV through a melt blending process to enhance PHBV toughness and flexibility. Incorporation of 5wt% polybutadiene grafted maleic anhydride (PB-g-MA) as a compatibilizer notably enhances mechanical properties. Furthermore, the study introduces the concept of thermoplastic vulcanizate (TPV) through melt blending using dynamic vulcanization (DV) to enhance mechanical properties, particularly the toughness of the 70/30 PHBV/ENR blends, identified as the optimal blending ratio based on prior research. The resulting blend vulcanizate (PHBV/ENRv) exhibits toughness values of 63.0 ± 14.8 J m− 1 and 24.4 ± 2.8 J m− 1 for blends with ENRv-25 and ENRv-50, respectively. These findings hold promise for advancing the design and development of biodegradable polymer blend systems, with a focus on enhancing processability and mechanical performance. [ABSTRACT FROM AUTHOR]

Annealing, a critical heat treatment process, is known for its effectiveness in reducing residual stresses in parts affected by temperature and pressure fluctuations during injection molding. This study explores the influence of annealing on residual stress distribution inmicrostructured parts made of three materials—polycarbonate (PC), polymethyl methacrylate (PMMA), and polystyrene (PS)—and featuring two depth-to-width ratios of microprismatic structures. This investigation combines molecular dynamics simulation with annealing experiments. Findings demonstrate that annealing significantly reduces residual stresses across all three materials, albeit with varying degrees of effectiveness. This variation in annealing efficacy is linked to the materials' properties, particularly the presence of a carbonate base in PC, which notably enhances its annealing response. In detail, for PC parts with a 1:1 depth-to-width ratio in micropillar structures, there was a 15.45% reduction in peak residual stress, while parts with a 2:1 ratio experienced a more substantial reduction of 41.56%. The study attributes these differences in annealing outcomes to the depth-to-width ratios of the microstructures, with larger cavity sizes allowing for more effective molecular chain stretching. [ABSTRACT FROM AUTHOR]

Liquid crystal polymer (LCP) composites are presented as lightweight, high-strength, thermoplastic composites. Fumed silica (FS), carbon black (CB), carbon nanostructures (CNS), and boron nitride (BN) added to the polyphenylene sulfide (PPS) increased the viscosity ratio of the PPS to the LCP. PPS filled with 5 wt.% FS was used to optimize injection molding conditions and had a viscosity ratio ranging from 2 to 13. Increasing fill time to 5 s brought about the highest tensile strength of 99 MPa and modulus of 12.5 GPa, while the tool and melt temperatures imparted no significant effect. Mechanical and thermal properties of select LCP materials processed using molding conditions optimized for the experimental materials are presented. Mechanical properties in the crossflow direction were lower than in the flow direction, which could be overcome with tool design and placement of valve gates to tailor the flow patterns. BN filled composites increased the thermal conductivity to a value of 0.26 W/mK at 16 wt.% loading. [ABSTRACT FROM AUTHOR]

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The extrusion procedure used to manufacture Short Fiber Reinforced Composites (SFRCs) results in significant anisotropy in the components due to the skin‐core structure. While there are existing accurate stiffness prediction methods available, there is still a need in engineering for an efficient and cost‐effective prediction method. This work proposes an efficient, low‐cost and effective stiffness prediction method for skin‐core structure using the orientation averaging method and series–parallel model. Initially, the sample is analyzed using industrial CT and metallographic microscopy to ascertain the fiber characteristics and skin‐core dimensions. Furthermore, it is presumed that the skin and core are distinct materials and their stiffness is determined using the orientation averaging method. Finally, the stiffness of the sample is determined by employing a series–parallel model for analyzing stress–strain transmission, which involved merging the skin and core components. Experimental and finite element results confirm the method's accuracy, boasting a calculation time of 31.36 s and a maximum stiffness error below 10%. This method is expected to be applied to automotive, construction and other engineering fields to meet the demand for fast, cost‐efficient and effective stiffness prediction of SFRCs. Highlights: A stiffness prediction method is proposed, which is no modeling required.Combined with Hashin‐Tsai, orientation average method and series–parallel model.The stiffness of skin‐core structure is predicted by this method within 31.36 s.This method can be extended to more complex fiber orientation examples. [ABSTRACT FROM AUTHOR]

Polyethersulfone (PES) is distinguished by its exceptional comprehensive properties, making it a highly valued engineering plastic employed in various cutting‐edge fields. However, the high cost of PES limits its wider application in industrial fields. Considering the cost‐reduction advantages of polymer foaming, PES foams were successfully prepared in this work using microcellular injection molding (MIM) and micro‐opening microcellular injection molding (MOMIM) foaming methods. Compared with the MIM foaming method, the PES foam samples prepared by the MOMIM foaming method have better microcellular structure and surface quality. As the micro‐opening distance increased, the cell density of the PES foam samples showed a gradual rise before plateauing, with the cell size remaining relatively constant. As a result, the density of the PES foam sample dropped to 1.07 g/cm3, which is 80.5% of the solid PES sample. Meanwhile, the mechanical properties of the PES foam samples remained robust, with both the specific flexural modulus and the specific flexural strength showing increases as the micro‐opening distance increased. The knowledge obtained from this study provides a method for preparing high‐performance PES foam materials, which will facilitate the application of PES in more civilian fields. [ABSTRACT FROM AUTHOR]

In this article, site‐specific functionalized keratoprosthesis (KPro) was accomplished to meet epithelial on‐growth on the anterior optical surface, inhibit cell adhesion on the posterior optic surface, and promote cell ingrowth at the peripheral tissue‐haptic‐flange interface toward tissue integration. Gelatin immobilization on PC4 hydrogel surfaces was achieved through acid hydrolysis followed by EDC/NHS chemistry, and polyethylene glycol‐diacrylate (PEGDA)‐modified inter‐penetrating network (IPN) surfaces were prepared using photo‐polymerization of ethylene glycol‐diacrylate (EGDA) for enhancing and inhibiting cellular growth, respectively. The surface chemical structures of modified hydrogels were characterized using attenuated total reflectance‐infrared (ATR‐IR) spectroscopy and a bicinchoninic acid (BCA) protein adsorption assay. Further, suitable differentially functionalized surfaces were prepared and characterized using the universal testing machine (UTM), refractometer, atomic force microscopy (AFM), and contact angle measurements to understand mechanical, optical, surface morphological, and wettability properties, respectively. Finally, in vitro site‐specific cell adhesion, cell inhibition, and cell ingrowth functionalities were tested using isolated goat corneal limbal epithelial stem cells and corneal stromal fibroblast cells, respectively. Overall, the two connective articles represent a successful endeavor to develop a more esthetically pleasing, mechanically stable, tissue‐free hydrogel KPro with site‐specific surface functionality nearly mimicking the cornea's functionality. A further pre‐clinical investigation is necessary to advance this functional novel KPro to reality, especially the tissue integration aspect. [ABSTRACT FROM AUTHOR]

In this paper, a nodal detection method for the detection and optimization of barrel helix offsets is proposed. The barrel used in this experiment is a 6-helix barrel. Moreover, the special properties of the film of Polyetheretherketone (PEEK) material are used to cover the surface of the barrel helix with a virtual in-mold decoration (IMD) film, and the unique nature of the film die offset in the IMD is utilized to detect the position of the barrel helix. The area with a large die index is the area with a large helix offset in the barrel, and the IMD die index is introduced to quantify the data. The IMD die index is used to determine the helix offset of the damaged barrel. The novelty of this work is that each node can use the die index to efficiently detect the position of the barrel helix deviation, carry out subsequent optimization and repair work through the optimization of the injection molding parameters and the design optimization of the barrel and verify the experiment by comparing the results. Through the steady-state simulation research mode, different permutations and combinations of the two process parameters are simulated to study their effects. Quantitative reference indicators include but are not limited to dependent variables such as the fluid flow velocity, shear rate, temperature distribution and phase transition, and the shear heating process of the injection screw is taken into account in the mold flow analysis to ensure that the die index value is more accurate. It can be seen from the analysis results that the temperature of the barrel changes after the groove depth and groove width are changed, and the effect ratio of the groove depth is lower than that of the groove width in the same degree of size change. [ABSTRACT FROM AUTHOR]

Electrochemically exfoliated graphene (EEG) is compounded with copolyamide 6/66 (PA6/66) to investigate the influence of the carbonaceous filler material on the thermal, rheological, and mechanical properties of the composite. Toward that end, the environmentally friendly electrochemical exfoliation in aqueous solution is further developed to furnish graphene in large quantities. Separating the exfoliation process from the incorporation into the polymer matrix by wet phase inversion (WPI) allowed in‐depth characterization of the EEG by scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy. The crystallinity of copolyamide 6/66‐EEG is significantly changed, as revealed by differential scanning calorimetry (DSC). Likewise, the new composite materials exhibit different flow properties, as well as increased mechanical reinforcement with additive concentration. This is proven by dynamic shear rheology and three‐point stress tests compared to the neat polymer. [ABSTRACT FROM AUTHOR]

In order to limit the ever-increasing consumption of new resources for material formulations, regulations and legislation require us to move from a linear to a circular economy and to find efficient ways to recycle, reuse and recover materials. Taking into account the principles of material circularity and waste reuse, this research study aims to produce thermoplastic composites using two types of industrial waste from neighbouring companies, namely waste polypropylene (wPP) from household production and carbon-fibre-reinforced epoxy composite scrap from a pultrusion company. The industrial scrap of the carbon-fibre-reinforced epoxy composites was either machined/ground to powder (pCFRC) and used directly as a reinforcement agent or subjected to a chemical digestion process to recover the carbon fibres (rCFs). Both pCFRC and rCF, at different weight ratios, were melt-blended with wPP. Prior to melt blending, both pCFRC and rCF were analysed for morphology by scanning electron microscopy (SEM). The pCFRC powder contains epoxy resin fragments with spherical to ellipsoidal shape and carbon fibre fragments. The rCFs are clean from the matrix, but they are slightly thicker and corrugated after the matrix digestion. Further, the morphologies of wPP/pCFRC and wPP/rCF were also investigated by SEM, while the thermal behaviour, i.e., transitions and changes in crystallinity, and thermal resistance were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The strength of the interaction between the filler (i.e., pCFRC or rCF) and the wPP matrix and the processability of these composites were assessed by rheological studies. Finally, the mechanical properties of the systems were characterised by tensile tests, and as found, both pCFRC and rCF exert reinforcement effects, although better results were obtained using rCF. The wPP/pCFRC results are more heterogeneous than those of the wPP/rCF due to the presence of epoxy and carbon fibre fragments, and this heterogeneity could be considered responsible for the mechanical behaviour. Further, the presence of both pCFRC and rCF leads to a restriction of polymer chain mobility, which leads to an overall reduction in ductility. All the results obtained suggest that both pCFRC and rCF are good candidates as reinforcing fillers for wPP and that these complex systems could potentially be processed by injection or compression moulding. [ABSTRACT FROM AUTHOR]

The completed study investigated the creation of Martian regolith simulant composite parts using injection molding and additive manufacturing. Traditional manufacturing techniques such as injection molding are not feasible on the Martian surface therefore in-situ processes must be developed using additive manufacturing processes to prepare habitats prior to having a human presence on the surface. The goal of this study was to investigate the impacts of additive manufacturing on the material property values between parts made using traditional injection molding and additive manufacturing. Martian regolith simulant composite pellets were created by combining a Martian regolith simulant at 40 wt% loading with polypropylene via twin screw extrusion. This material was then used to create test specimens using injection molding and additive manufacturing. Samples underwent tensile, flexural, Izod impact, and immersion density tests according to ASTM International and standardized test instructions. Additive manufactured parts saw a nearly 40% reduction in tensile and flexural strength with more than double the tensile modulus when compared to injection molded parts. The flexural modulus for additive manufacturing was around 36% that of the injection molded part with a minor decrease in density of around 13%. The collected test results suggested that while there were differences in the material property values between the manufacturing processes, a more interesting foaming behavior of the extrudite was observed during the additive manufacturing process resulting in an extremely rough and pitted surface. This rough surface finish was a stark comparison to the smooth injection molded parts. This observed foaming behavior in the polymeric composite material during thermal processing prompted the theory that thermal releases from the Martian regolith simulant was the most likely cause of the observed differences. Pellet surface moisture tests, Martian regolith simulant thermogravimetric analyses, and literature reviews of thermal decomposition of the Martian regolith simulant constituents revealed that most likely olivine releases oxygen and hydrated silica releases water during the thermal processing of the Martian regolith simulant composite. During a closed mold process such as injection molding, these volatile gases are forced out of the part by the pressures of the molding process, but in an open to atmosphere process such as additive manufacturing these gases foam to the surface during cooling leaving the part with an inferior surface finish. [ABSTRACT FROM AUTHOR]

Injection molded (IM) and additively manufactured (AM) selective laser sintered (SLS) Nylon-12 was irradiated with gamma irradiation to determine the damage mechanism. Modulated differential scanning calorimetry was used to separate the thermodynamic (reversible) and kinetic (non-reversible) heat flows and evaluate how manufacturing method and radiation dose impacted the thermodynamics of melting, along with thermogravimetric analysis (TGA) to investigate thermal stability. Tensile testing and fractography were utilized to evaluate mechanical behavior. The bulk crystallinity of SLS Nylon-12 was not significantly affected by gamma radiation and was estimated to be 38.2 ± 2.3% averaged over all doses. Ultimately, 20 MRad of exposure to SLS Nylon-12 reduced the samples' early-stage thermal stability by ca. 14.3 °C as measured by TGA, suggesting that the radiation may have contributed to breaking chemical bonds and/or affecting chain entanglement within the polymer structure. The ultimate tensile strength (UTS) decreased with irradiation, suggesting that radiation exposure has a weakening effect (possibly due to chain scissioning) as well as degrading particle coalescence with sintered Nylon-12. SLS Nylon-12 is more susceptible to radiation; the average UTS of Nylon-12 SLS and IM decreased by 54% and 9%, respectively. Injection molding completely transforms α -form to γ -form and results in a lower void volume than SLS. [ABSTRACT FROM AUTHOR]

Material extrusion and injection molding are prevalent in polymer processing, but wood fiber‐reinforced polymer composites offer eco‐friendly alternatives for industries like automotive, and aviation. Our study explores biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP). BCTMP is rich in cellulose and hemicellulose and quite hydrophilic, while PP's hydrophobic structure creates a disconnect to creating a composite of the two. Traditional methods add costly coupling agents like maleic anhydride polypropylene (MAPP) in an attempt to enhance the adhesion properties of wood‐plastic composites. However, it is worth noting that even in the presence of MAPP, PP maintains its high hydrophobicity and low surface energy, despite exhibiting considerable heterogeneity. Further complexity arises from the thermal degradation characteristics of BCTMP during the melting processing of PP. Our proposed method involves premixing via cryo and planetary ball milling. This boosts PP and BCTMP adhesion, enhancing dispersion quality and mechanical properties without needing coupling agents. Moreover, the premixing of BCTMP and PP forms a thermal buffer layer around BCTMP, minimizing its thermal degradation during processing. This process also ensures even distribution of BCTMP into PP, resulting in a 200% rise in Young's modulus with 30 wt% BCTMP without compromising ultimate tensile strength. Highlights: Exploration of biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP) thorough injection moldingImplementation of premixing to enhance PP/BCTMP adhesion without coupling agentsPremixing reduces thermal degradation of BCTMP, enhances dispersion, and improves mechanical propertiesAchieving a 200% increase in Young's modulus with 30% BCTMP incorporation, while maintaining ultimate tensile strength [ABSTRACT FROM AUTHOR]

Microinjection molding (μIM) is characterized by high shearing and cooling rates, resulting in higher a degree of filler orientation which impairs the electrical conductivity (σ) of conductive filler‐containing polymer composites when compared with that of compression molding and conventional injection molding processes. In this study, polypropylene/polyamide 6/multiwalled carbon nanotubes (PP/PA6/CNT) composites were used as the model system to investigate how blending sequence, injection speed, and component mass ratios affected the morphology and σ of PP/PA6/CNT microparts. The results demonstrated that CNTs exhibited a higher affinity for the polar PA6 phase and they tended to be preferentially distributed in PA6 domains. The deformation and coalescence of CNT‐rich PA6 phase promoted the creation of an intact and continuous filler network structure along the flow direction under the influence of high shearing conditions in μIM. When the mass ratio of PP:PA6 was 70:30 and the concentration of CNT was 7 wt%, the micropart possessed the highest σ (1.2 × 10−6 S/m) when compared with their PP/CNT (4.4 × 10−9 S/m) and PA6/CNT (3.4 × 10−10 S/m) counterparts. Higher injection speeds resulted in higher degree of CNT orientation, which negatively affected the σ of subsequent moldings. This work established an approach for producing electrically conductive microparts that demonstrate promising applications in the fields of electronics, automotive, and microsystems among others. Highlights: PP/PA6/CNT composites were used as model systems for microinjection molding.The electrical conductivity was improved by shear‐induced deformation of CNT‐rich phase.The properties of PP/PA6/CNT microparts were affected by process parameters. [ABSTRACT FROM AUTHOR]

This study investigates the effect of high processing temperatures used in the medical syringe factory in Iraq on some rheological and morphological properties of polypropylene. Ten samples consisting of 50% virgin (pure) PP and 50% recycled PP were processed. The mold temperature was varied in the range of 190℃ to 210℃, while maintaining the pressure and secondary time at 78 bar and 0.5 seconds, respectively. The results showed that the density decreased by 45% as the injection temperature increased. In contrast, the Melt Flow Index (MFI) increased by 60% with rising injection temperatures. The results also indicated a severe effect of high processing temperatures on the samples, which was evident in the FTIR test, where the intensity of the peaks changed significantly compared to virgin PP. The DSC test revealed that the Tg value increased to 15.1℃ for recycled PP, compared to 9.8℃ for the virgin sample. [ABSTRACT FROM AUTHOR]

Effects of thermoplastic polyurethane (TPU) types (Recycled (R) and Virgin (V)) composites with 15 wt% and 30 wt% oakwood flour addition were studied. Selected physical, mechanical, morphological, and thermal properties of resulting polymer composites were analyzed. Test samples were manufactured using injection molding, except that abrasion resistance specimens were manufactured using a compression molding process. The findings indicated that the types of TPU and filler contents played a significant role in the density and mechanical properties of the TPU test samples. The increased oak wood flour contents in both TPU types showed improvement in density, tensile modulus, hardness, flexural strength flexural modulus, dynamic impact strength, and yield strength of the composite while decreasing the elongation at break values. In addition, both TPU types and filler contents significantly affected the densities of VTPU and R-TPU. The TPUs type, filler content, and cycle-rpm affected Taber's abrasion resistance values. Weight loss, which increased with the number of cycles for the control samples, decreased with increasing wood flour content. This study aimed to provide an overview of the effect of the wood flour content in the manufacturing of thermoplastic-reinforced composites and to provide a basis for further research and development efforts. [ABSTRACT FROM AUTHOR]

Chitin and chitosan are versatile and valuable biomaterials, with chitosan being abundantly found in the exoskeletons of crustaceans, insects, arthropods, and mollusks. The chemical extraction of chitin involves a series of steps, including deproteinization, demineralization, and decolorization. Chitosan is often combined with various polymeric materials, and polymer blending can enhance the mechanical properties of the resulting bioproduct. In this study, composites of poly(lactic acid) (PLA) with chitosan (Ch) and cellulose acetate (CA) were successfully fabricated using extrusion and injection molding techniques. The chitosan content, ranging from 0 to 7.5 wt. %, was incorporated into the PLA matrix to assess the impact of filler content on the mechanical and morphological properties of the composites. The chitosan powder was first alkalized and then etherified to obtain modified chitosan, specifically o-carboxymethylated chitosan (O-CMCh). The addition of chitosan led to a reduction in tensile strength, flexural strength, modulus of elasticity, and impact strength. However, the hardness of the composite improved with the inclusion of chitosan. The mesoporous structure of chitosan was characterized using nitrogen adsorption and desorption measurements. Morphological analysis revealed that the composite containing 3.75 wt. % chitosan exhibited significantly less fracture surface compared to other composites. HIGHLIGHTS: Chitosan is obtained from chitin through deacetylation and chemical modification (O-CMCh) is achieved through alkalization followed by etherification. PLA/CMCh-CA composites fabricated through extrusion and injection molding. The tensile strength gradually decreased from 55.09 to 1.3 MPa. The Flexural strength drastically declined from 93.37 to 19.10 MPa. The impact strength decreased with addition of Ch whereas, hardness increased. [ABSTRACT FROM AUTHOR]

This paper proposes a multi-objective optimization method for injection molding, combining the random forest (RF) model optimized using the light spectrum optimizer (LSO) with the non-dominated sorting whale optimization algorithm (NSWOA), to tackle the quality defects of warpage deformation and volume shrinkage commonly observed for the glass fiber injection molded product. Based on the simulation results of central composite face centered design (CCF), the model for control of injection molding quality defects using LSO-RF is constructed. NSWOA is used for multi-objective optimization to obtain the Pareto solutions, and the critic method is employed to determine the optimal process parameter scheme. Then, the optimal process parameter scheme is inputted to Moldflow for simulation verification. The validation results demonstrate that the LSO-RF model achieves prediction errors within 3 % for warpage deformation and volume shrinkage, indicating good predictive accuracy. The optimized warpage deformation and volume shrinkage are 0.3519 mm and 7.0930 %, respectively. Compared to the pre-optimized state, the warpage deformation decreased by 32.57 % and the volume shrinkage decreased by 15.93 %, indicating a significant improvement in molding quality for the glass fiber injection molded product. [ABSTRACT FROM AUTHOR]

Hybrid manufacturing processes integrate multiple manufacturing techniques to leverage their respective advantages and mitigate their limitations. This study combines additive manufacturing and injection molding, aiming to efficiently produce components with extensive design flexibility and functional integration. The research explores the interfacial fusion bonding of hybrid additively manufactured components under torsional loading. Specifically, it examines the impact of various surface treatments on injection molded parts and the influence of different build chamber temperatures during additive manufacturing on torsional strength. Polycarbonate components, neat, with glass or carbon fiber-reinforcement, are produced and assessed for dimensional accuracy, torsional strength, and fracture behavior. The findings emphasize the critical role of surface treatment for the injection molded components before additive manufacturing. Additionally, the study identifies the influence of chamber temperatures on both dimensional accuracy and torsional strength. Among all investigated materials, plasma-treated neat samples exhibited the best torsional strength. The torsional strength was increased by up to 87 % by actively heating the build chamber to 186 °C for neat polycarbonate. These insights aim to advance the quality and performance of hybrid additively manufactured components, broadening their application potential across diverse fields. [ABSTRACT FROM AUTHOR]

Conventionally and digitally manufactured removable complete dentures with different dentition forms were examined for manufacturing accuracy (trueness, precision), fracture forces under torsional loading and subsequent repairability. A total of 90 mandibular prostheses were manufactured. Ten were made using the injection molding technique and finished with prefabricated teeth. 40 bases each, were manufactured subtractively and additively. Digitally the prosthesis' dental arch was divided either into two quadrants or three sextants, or kept as full arch. Afterwards, ten additive and subtractive bases were finished with prefabricated teeth and ten of each with milled quadrants, sextants and full arches. After manufacturing, all specimens were rescanned for accuracy comparisons using the Root Mean Square (RMS). Lastly, all specimens were tested to failure under torsional loading. Conventionally manufactured dentures showed the greatest deviation in accuracy. The type of base manufacturing did not determine the fracture resistance of the prostheses. The dentition form had a significant influence. While prefabricated teeth (86.01 ± 19.76 N) and quadrants (77.89 ± 9.58 N) showed a low fracture resistance, sextants (139.12 ± 21.41 N) and full arches (141.05 ± 17.14 N) achieved the highest fracture forces. Subtractive bases with prefabricated teeth or quadrants were assessed to be repairable, digital dentures with full arch were assessed as not repairable. The presented testing set-up is suitable to determine the fracture behavior of dentures rather than of standards. With the possibility of digital design and individual manufacturing, dentures' mechanical stability can be significantly increased, especially with suitable dentition forms. • In-vitro testing setup for torsional loading of removable complete dentures. • Investigating manufacturing accuracy, fracture forces and repairability of dentures. • Analyzing manufacturing methods alongside various dentition forms. • Base manufacturing affects resistance and repairability less than dentition choice. [ABSTRACT FROM AUTHOR]

This research aims to enhance the design of an injection mold in order to minimize ejection time and increase temperature uniformity by repositioning cooling channels. For 3D transient thermal simulations, the ANSYS finite element method (FEM) program was employed, while the MATLAB program was used for optimization. It was discovered that the method could be used successfully to optimize the design of Conformal Cooling Channels (CCCs) in injection molds. The objective function value of the optimized model represents a near 40% improvement in relation to the initial model. The combined parameterization, simulation, and optimization method has proven beneficial for enhancing the arrangement of channels in an injection machine mold. The methodology is generalizable. As such, it can be employed in any industrial applications involving injection molding machines, for the improvement of the quality of the manufactured part. [ABSTRACT FROM AUTHOR]