Search Results (1,707)

This contribution presents a simulation-based approach for optimizing injection molding processes using digital twins. It combines surrogate modeling via response surface methodology (RSM) with the evolutionary algorithm NSGA-II to efficiently capture complex relationships between process parameters and objectives. A key element is the adaptive enhancement of the training dataset within the decision-relevant region of interest (ADEROI) by a modified greedy max–min algorithm. This strategy closes data gaps, improves model accuracy in the potentially optimal region, and directs additional simulations to informative areas. Leave-one-out (LOO) and hold-out (HO) cross-validations show strong root mean square error (RMSE) and $R^2$ values for deformation, shrinkage, cycle time, and mass. NSGA-II converges after 403 generations and results in 191 Pareto-optimal solutions, which are consolidated into preference-consistent operating points. These points make trade-offs between analyzed objectives’ deformation, shrinkage, and cycle time explicit for process pre-design. Preferred solutions are identified through weighted sums of normalized objectives and inversely mapped process parameters. Their agreement with the physics-based digital twin at the hundredths level supports the plausibility of the selected operating points within the investigated simulation-based workflow. A retrospective benchmark against a scaled single-stage LHS baseline shows that ADEROI achieves ROI-equivalent point density with fewer simulation runs for the investigated case, reducing the estimated runtime by $39.1\%$ and resulting in a $1.64\times$ speed-up. The quantitative validation is limited to one thin-walled PP keyholder component; further geometries, mold layouts, and polymer materials are required to empirically assess generalizability. Full article

This study aims to develop sustainable conductive nanocomposites based on poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends reinforced with multi-walled carbon nanotubes (MWCNT) and graphene nanoplatelets (G), focusing on their multifunctional performance. The novelty lies in the production of hybrid nanocomposites based on PLA/PCL blends with MWCNT/G using conventional industrial processing techniques, enabling the development of eco-friendly nanocomposites with tailored electrical, mechanical, and electromagnetic properties. The nanocomposites were prepared by twin-screw extrusion followed by injection molding. Rheological, scanning electron microscopy (SEM), mechanical, thermal, thermomechanical, electrical conductivity, and electromagnetic shielding properties were systematically evaluated. From a rheological perspective, the PLA/PCL/MWCNT and PLA/PCL/MWCNT/G nanocomposites exhibited a plateau at low frequencies, associated with the formation of a percolated network. This was confirmed by the significant increase in electrical conductivity and electromagnetic shielding response. The morphology observed by SEM showed a refinement of the PCL phase in the PLA matrix with the incorporation of MWCNT. The PLA/PCL/MWCNT/G (4/2 parts per hundred resin, phr) nanocomposite showed a 309% increase in impact strength compared to neat PLA, while maintaining the heat deflection temperature (HDT). The elastic modulus exceeded 2300 MPa and accelerated the crystallization process by more than 15 °C compared to PLA, which makes it important to reduce injection molding time. Additionally, it exhibited the highest electrical conductivity level, around 6.79 × 10⁻⁵ S/cm, which resulted in improved electromagnetic shielding performance in the 8.2–18 GHz range, highlighting the synergistic effect between 1D and 2D fillers. The developed PLA/PCL/MWCNT and PLA/PCL/MWCNT/G nanocomposites demonstrate potential for antistatic applications, combining sustainability with multifunctional performance and industrial scalability. Full article

Eco-friendly biocomposites were prepared from poly(lactic acid) (PLA) plasticized with polyethylene glycol (PEG) and reinforced with Moroccan sugarcane bagasse fibers at 5, 10 and 15 wt%. The aim was to enhance PLA ductility through PEG incorporation while valorizing locally available lignocellulosic residues. Two processing methods, injection molding and melt extrusion additive manufacturing (MEX, 3D printing), were employed to investigate the influence of manufacturing method on the morphological, thermal, rheological and mechanical properties of the composites. Thermal analysis confirmed that PLA maintained its stability within the processing temperature range, supporting its suitability for MEX. Morphological observations revealed improved fiber dispersion and reduced porosity in injection-molded samples, whereas MEX-printed parts exhibited visible interlayer voids. These microstructural differences explained the superior tensile strength and modulus of injection-molded specimens compared to MEX ones. Full article

Large glass fiber-reinforced polypropylene (GF-PP) shells are widely used in HVAC and automotive industries, but their injection molding suffers from severe warpage deformation, residual stress concentration, and inaccurate mechanical performance prediction due to neglected molding history. This study proposes an integrated optimization framework for a 30% GF-PP fan face shell. The optimal two-gate molding configuration was determined via Moldflow simulation. A Central Composite Design (CCD) combined with NSGA-II was used to optimize process parameters for minimizing warpage and residual stress. A Moldflow-Ansys co-simulation process was established to characterize fiber orientation-induced mechanical anisotropy, and full-scale mold trials were conducted for validation. The optimized process reduced maximum warpage by 58.03% (from 5.299 mm to 2.224 mm) and residual stress by 13.67% (from 54.93 MPa to 47.42 MPa). The average tensile modulus along the flow direction was 1.85 times that perpendicular to the flow direction. Mold trial results showed a warpage prediction error of only 7.583%. The proposed framework effectively addresses the critical quality issues in large GF-PP injection molding, providing a systematic engineering solution for molding quality control and accurate performance characterization. Full article

The accuracy of gears is a determining factor for their functionality, reliability, and durability in various mechanical systems. Two widely used technologies for producing plastic gears are injection molding and 3D printing, each having its own advantages and limitations. Injection molding is a traditional method for mass production that offers high productivity but is sensitive to parameters such as temperature, pressure, and cooling, which can lead to shrinkage and dimensional instability. On the other hand, 3D printing is gaining popularity due to its flexibility, rapid prototyping capabilities, and the possibility of producing small series without the need for expensive tooling. In the present study, the accuracy of plastic gears with module 2 and module 3, manufactured using both technologies, was investigated and compared. Measurements were performed on three main parameters: span measurement, chordal tooth thickness, and measurement over pins. The obtained data were statistically analyzed and classified according to the DIN 3962/3963 and ISO 628 accuracy standards. 3D-printed gears demonstrated lower standard deviation (0.0079–0.0083 mm) and improved repeatability compared with injection-molded gears (0.0131–0.0189 mm), achieving DIN 10–14 accuracy classes. Unlike previous studies that compare different materials or technologies separately, this work directly compares both simultaneously under controlled conditions, revealing that material selection (CF-reinforced vs. unfilled POM) may influence dimensional outcomes as strongly as the manufacturing method. These findings provide practical guidance for selecting production routes for low-to-medium precision polymer gears under the tested conditions. Full article

Thermoplastic starch (TPS) and polyvinyl alcohol (PVA) blends were prepared over the full compositional range (0–100 wt% PVA) by solvent-free twin-screw extrusion and injection molding. This enabled a systematic evaluation of structure–performance–disintegration relationships under industrially relevant conditions. The blends exhibited clear composition-dependent trends in thermal and mechanical behavior. Increasing PVA content from 0 to 100 wt% raised the onset degradation temperature (T5%) from 160.5 °C to 290.5 °C and increased crystallinity from near zero to 12.24%. Mechanically, the response evolved from a rigid TPS-rich state to a ductile PVA-rich one. FTIR and SEM analyses indicated partial compatibility, with limited molecular-level interactions leading to morphologically homogeneous but only partially miscible blends. Under simulated composting conditions, all formulations showed substantial physical disintegration. PVA-rich blends (≥60 wt%) disintegrated rapidly (>80% mass loss within two days), primarily by dissolution rather than microbial degradation. Overall, this work provides a comprehensive, scalable assessment of solvent-free TPS/PVA blends, clarifies their limited compatibility under melt processing, and demonstrates how composition can be used to tailor structure, performance, and disintegration behavior across the full compositional range. Full article

The increasing demand for porous stainless-steel materials produced by selective laser melting (L-PBF) for biomedical implants, filtration systems, heat exchangers, and energy devices has created an urgent need to improve their mechanical performance. Optimizing process parameters and microstructural properties is therefore critical for enhancing the overall functionality and reliability of L-PBF porous stainless-steel structures. This paper studies the effect of an aging heat treatment on the mechanical properties of L-PBF specimens, manufactured with stainless steel Uddeholm Corrax powders. The porosity was selected to be about 3%, based on manufacturer’s experience on the production injection mold inserts, with the ability to drain air. To reach this porosity, a set of manufacturing variables were selected, quantified in terms of VED (Volumetric Energy Density) of 59.01 J/mm³. The analysis of the mechanical behavior was focused on the compressive and flexural strength, dynamic Young’s modulus and the energy dissipation during earlier fatigue loading cycles. This study concluded that the heat treatment produces a negligible effect on dynamic Young’s modulus and increases the bending strength by about 25% and the compressive plateau strength by about 17%. Both specimens’ batches exhibit similar fatigue strain accumulation for cyclic compressive tests. Full article

In a steel continuous casting mold, argon bubbles injected through the submerged entry nozzle undergo transport, coalescence, and turbulent breakup, producing a polydisperse bubble swarm that affects flow stability and defect formation. In this study, an Euler–Lagrange model coupled with bubble collision coalescence and turbulence-induced breakup sub-models was established and validated using water model observations. Three daughter-bubble volume distribution models were compared in terms of bubble-cloud morphology, number-fraction distribution, and median-diameter evolution at different gas flow rates. For the median bubble diameter at different gas flow rates, the M-type model gives the lowest mean absolute error of 0.0349 mm. Large bubbles with diameters greater than 2.5 mm accounted for about 4% of the total number and were mainly concentrated near the SEN, whereas small bubbles with diameters of 1.0–1.5 mm accounted for about 60% and were dispersed throughout the upper recirculation region. Mechanism analysis further shows that bubble transport is drag-dominated in the high-velocity jet region, while buoyancy becomes more important in weaker flow regions; turbulent breakup is localized mainly in high-dissipation regions. Full article

Increasing regulatory demands for high-quality plastic recycling create a strong need for novel tracer systems that enable reliable polymer identification and sorting. This feasibility study evaluates germanium nanocrystals (GeNCs) as Raman-detectable tracer materials in polypropylene (PP). The synthesis of GeNC/PP composite materials possessing various GeNC contents via a solvent-based intercalation process followed by compounding and injection molding is reported. Hydride-terminated GeNCs were synthesized and subsequently functionalized with dodecyl ligands to ensure chemical stability, compatibility with the polymer matrix, and processability under conventional melt-processing conditions. The dodecyl-functionalized GeNCs were successfully stabilized and homogeneously integrated into the PP matrix. Raman spectroscopy demonstrates the clear detection of GeNCs within the composites through a characteristic Ge–Ge optical phonon mode at 296 cm⁻¹, which is well separated from the intrinsic Raman bands of polypropylene. The Raman signal intensity increases systematically with increasing GeNC concentration. Raman mapping reveals an overall homogeneous distribution of the nanocrystals within the polymer, while a slight tendency toward agglomeration is observed at higher loadings. These results demonstrate that GeNCs are well suited as optically detectable tracers for polypropylene and can be reliably identified using Raman spectroscopy, highlighting their potential for tracer-based sorting concepts in advanced recycling and digital material passport applications. Full article

Plastic injection molding in cleanrooms involves high thermal loads and strict particle limits. The hot surfaces of the injection molding machine and peripherals increase the cooling demand of the heating, ventilation, and air conditioning system to an undefined amount. Moreover, the generation of buoyancy-driven plumes has the potential to disturb the cleanroom airflow around the injection mold, thereby risking cross contamination of the manufactured components. The present study quantifies the global heat load of injection molding machines in an ISO Class 7 cleanroom with a laminar flow microenvironment around the mold. Therefore, a measurement-based method to determine the heat load of a complete injection molding production cell is applied to a hydraulic and an electric machine. This method revealed that the heat load of the isolated machines is process-independent, whereas the total heat load of the complete production cell scales linearly with mold temperature. Moreover, the emitted heat to the cleanroom is considerable lower than the injection molding machine’s installed power. Secondly, the airflow regime and particle transport in the mold area are analyzed. This is achieved by means of schlieren visualization and aerosol measurements. The introduction of a modified Archimedes number, incorporating mold size and convective heat flux, has led to the observation of a correlation between flow regimes and the resulting particle load. This enables the selection of case-dependent FFU velocities that deviate from the conventional recommendation of an air speed of 0.45 m/s ± 20%. Despite the presence of a filter-fan unit, the particle load near the injection mold cavity increases for flow conditions that exceed a critical Archimedes number. Full article

As extreme-scale manufacturing evolves, the dynamic response of heavy moving components under ultra-high loads becomes a critical design challenge. This study focuses on friction-induced vibration of a more than 30-ton movable mass during the mold-opening stage in a two-platen machine with a clamping force >17,000 kN. A mathematical model and a validated rigid/flexible multibody dynamics model with PID co-simulation were developed to analyze transient vibration using maximum acceleration amplitude and stability time as core metrics. The results show vibration stems from imbalance between anti-opening resistance and hydraulic driving force, amplified by vacuum collapse, static-to-dynamic friction transition at slide feet/rail interface and PID overshoot, featuring high amplitude density (>0.75 g), transience (<50 ms) and high impact (>60,000 N). The maximum vibration acceleration amplitude remains 79.22% even after there is no mold vacuum suction, indicating that a static friction force other than the vacuum suction is the dominant factor resulting in a severe friction-induced vibration. These mechanistic insights establish an applicable framework for the dynamic optimization of the heavy components in extreme-large-scale manufacturing equipment. Full article

Bone tissue engineering requires biomimetic materials; however, pure polylactic acid (PLA) exhibits limited osteoinductivity and produces acidic byproducts upon degradation. To address these limitations, this study fabricated PLA scaffolds using fused-deposition modeling (FDM) with four distinct lattice structures (rectangular, triangular, gyroid, and 3D honeycomb) and incorporated hydroxyapatite (HA) at 0, 10, 20, and 30 wt% via injection molding. Mechanical properties were evaluated via compression, three-point bending, and tensile testing. The results revealed that increasing HA content significantly reduced structural strength and increased brittleness across all test modes. Specifically, specimens with 30 wt% HA exhibited a 70.8% reduction in bending strength relative to pure PLA (from 58.60 MPa to 17.07 MPa), while tensile strength decreased by 46.1% at just 10 wt% HA (from 37.54 MPa to 20.23 MPa). Although the triangular lattice achieved the highest absolute compressive load, the rectangular lattice provided a superior load-to-weight ratio and greater plastic deformation capacity before fracture. Consequently, these findings indicate that the rectangular pattern at 70% infill density combined with HA addition limited to ≤10 wt% represents the most mechanically balanced design for bone defect repair applications. Based on the mechanical characterization performed in this study, and drawing on published evidence regarding the biological properties of PLA/HA composites, these scaffolds represent a mechanically promising candidate for further evaluation in bone tissue regeneration. Biological validation through in vitro and in vivo studies is required before clinical relevance can be established. Full article

Injection molding is essential for mass-producing soft contact lenses, yet molding-induced deformation remains a decisive factor for optical quality. This study systematically evaluated the impact of resin mold design factors (optical zone (OZ) radius of curvature and resin mold thickness) and injection molding parameters (holding pressure and injection speed) on the properties of a dry-state lens (dry lens) using an L18 orthogonal array. The results demonstrated that optimizing the resin mold thickness to 0.9 mm reduced astigmatism by approximately 95%, while high holding pressure and low injection speed improved structural stability. Notably, the findings suggest that the refractive power of the dry lens is more strongly governed by macro-level curvature fluctuations and internal stress distributions arising from the resin mold thickness and shape than by the wavefront aberrations of the resin mold itself. Designs with a smaller radius of curvature (R = 6.5 mm) exhibited substantial power deviations of up to +2.8 D, whereas deviations remained within ±0.2 D for designs with a larger radius of curvature (R = 8.5 mm). For high-precision lens manufacturing, it is indispensable to incorporate a resin mold design that accounts for deformations induced during molding. This study provides comprehensive guidelines for achieving high-quality products by detailing the relationship between injection molding and design. Full article

In response to the growing demand for sustainable manufacturing, 3D printing using recycled polyethylene terephthalate (rPET) offers a novel waste-to-value conversion method. Although the application of rPET in additive manufacturing has attracted significant attention from both the academic and industrial sectors, substantial challenges impede its further development, notably the high processing shrinkage and poor mechanical properties of the final product. This study focuses on developing recycled PET-based composites with favorable processing, thermal, and mechanical properties. Regranulates were produced via twin-screw extrusion using PET flakes, multifunctional chain extenders, and short glass fibers (GFs). The rPET-GF composites were characterized in terms of their processing, thermal, thermomechanical, and mechanical properties. Epoxy-functional chain extender modification effectively increased the molecular weight and improved the processability, whereas GF reinforcement enhanced the tensile properties of both injection-molded and FDM-manufactured parts. A primary advantage of the rPET systems developed in this study is their delayed crystallization kinetics. These findings highlight the significant potential of the composites developed herein for extrusion-based additive manufacturing (MEX-AM), as delayed crystallization facilitates enhanced interfacial adhesion, lower volumetric shrinkage, and superior dimensional stability. Full article

S136 mold steel is widely used in the injection molding industry due to its excellent properties. However, during actual production, the mold is inevitably exposed to harsh service conditions involving high temperature, high pressure, chemical corrosion, and mechanical wear, leading to risks of failure caused by pitting corrosion, intergranular corrosion, electrochemical corrosion, selective dissolution, and surface fatigue wear. To enhance the surface protection performance of the mold, a TiC-reinforced 440C stainless steel composite coating was fabricated on the S136 substrate using plasma spray welding technology. Composite powders with different TiC contents (wt.%) were prepared via mechanical mixing. The phase composition, microstructure, microhardness, corrosion resistance, and wear resistance of the coatings were characterized by XRD, SEM, Vickers microhardness tester, electrochemical workstation, and vertical universal friction and wear tester. Furthermore, the corresponding strengthening mechanisms were elucidated. The results show that the incorporation of TiC refines the microstructure and synergistically enhances both corrosion and wear resistance. Among the tested coatings, the one with 1.0 wt.% TiC exhibits the best overall performance, with a significantly increased microhardness of 858.85 HV (approximately 1.5 times that of the substrate), an Ecorr of –0.286 ± 0.002 V, an Icorr of 4.51 × 10⁻⁷ A·cm⁻², and a friction coefficient of 0.591. This study provides important theoretical and technological insights for the surface strengthening of S136 mold steel using plasma spray welding of TiC/440C composite coatings to improve corrosion and wear resistance and extend service life. Full article