Fast Manufacturing Research Articles

Effects of manufacturing parameters on mechanical interface properties of thin wood veneer laminates

This study explores fast manufacturing techniques for thin wood laminates made from European beech veneers and 1-component polyurethane adhesive. Manufacturing factors such as pressure and pressing time are investigated following well-established standards developed for fibre-reinforced materials (ASTM D5528 and ASTM D7905). Mode I and Mode II interlaminar fracture properties are calculated to quantify the effects of the different manufacturing techniques on the bond quality. It is found that pressing time and pressure can be minimised to 10 minutes and 0.1 MPa from 75 min and 1.0 MPa as suggested by the adhesive manufacturer, without reducing critical Mode I strain energy release rates of around 500 to 600 J/m2. However, the standard deviation of these properties increases with decreasing pressure and pressing time. Furthermore, the results show that while ASTM D5528 for Mode I testing can be used with thin wood veneer laminates, the ASTM D7905 for Mode II fracture testing is not directly applicable to these materials.

New therapy against breast cancer: mRNA cancer vaccines

Breast cancer is the common diagnosed cancer around the world with high rate of incidence and mortality. Nowadays, although endocrine therapy, and anti-HER2 targeted therapy got a advance in chemotherapy in the past decades, but our studies face the challenge about the relapse and metastasis of breast cancer. Human beings are in need of innovative treatment strategies to change this situation. Immunotherapy has become the mainstream cancer treatment strategy in recent years. mRNA tumor vaccine has gradually occupied the main position in breast cancer treatment with its special advantages of low toxicity, fast manufacturing and safety, high efficiency, and mRNA vaccine has great advantages over current vaccines. This article mainly reviews the progress of mRNA vaccine in breast cancer, and summarizes the possible challenges.

End-to-End Continuous Small-Scale Drug Substance Manufacturing: From a Continuous In Situ Nucleator to Free-Flowing Crystalline Particles

In the evolving landscape of pharmaceutical manufacturing, a comprehensive continuous production process is being crafted for the small-scale production of active pharmaceutical ingredients. This study focuses on continuous crystallization with separate nucleation and crystal growth units, as well as continuous downstream processing, encompassing filtration, washing, and drying until the formation of free-flowing particles. We introduce a novel continuous nucleator designed based on solubility data and produced via 3D printing, enabling the fast and precise small-scale manufacturing of a nucleator meeting the requirements for nucleation and further growth processes. The nucleator is evaluated with regard to its suitability for continuous long-term operation across various coupled crystallizers. As a practical application example, it is connected to a slug flow crystallizer to enable high-quality continuous crystallization. Additionally, the full integration of downstream processes using a continuous vacuum screw filter to achieve free-flowing product particles is realized. Even under non-optimized process conditions, with the help of the in situ generation of nuclei, free-flowing product particles are successfully obtained. This is particularly useful during drug development when no material is available for seed addition and to quickly obtain products for further characterization.

Advances in volumetric bioprinting.

The three-dimensional (3D) bioprinting technologies are suitable for biomedical applications owing to their ability to manufacture complex and high-precision tissue constructs. However, the slow printing speed of current layer-by-layer (bio)printing modality is the major limitation in biofabrication field. To overcome this issue, volumetric bioprinting (VBP) is developed. VBP changes the layer-wise operation of conventional devices, permitting the creation of geometrically complex, centimeter-scale constructs in tens of seconds. VBP is the next step onward from sequential biofabrication methods, opening new avenues for fast additive manufacturing in the fields of tissue engineering, regenerative medicine, personalized drug testing, and soft robotics, etc. Therefore, this review introduces the printing principles and hardware designs of VBP-based techniques; then focuses on the recent advances in VBP-based (bio)inks and their biomedical applications. Lastly, the current limitations of VBP are discussed together with future direction of research.

Continuous Stereolithography 3D Printing of Multi-Network Hydrogels in Triply Periodic Minimal Structures With Tunable Mechanical Strength for Energy Absorption

Abstract This work presents a fast additive manufacturing (AM) protocol for fabricating multi-network hydrogels. A gas-permeable PDMS (polydimethylsiloxane) film creates a polymerization-inhibition zone, enabling continuous stereolithography (SLA) 3D printing of hydrogels. The fabricated multi-bonding network integrates rigid covalent bonding and tough ionic bonding, allowing effective tuning of elastic modulus and strength for various loading conditions. The 3D-printed triply periodic minimal structures (TPMS) hydrogels exhibit high compressibility with up to 80% recoverable strain. Additionally, dried TPMS hydrogels display novel energy/impact absorption properties. By comparing uniform and gradient TPMS hydrogels, we analyze their energy/impact absorption capability of the 3D-printed specimens. We use finite element analysis (FEA) simulation studies to reveal the anisotropy and quasi-isotropy behavior of the TPMS structures, providing insights for designing and controlling TPMS structures for energy absorption. Our findings suggest that gradient TPMS hydrogels are preferable energy absorbers with potential applications in impact resistance and absorption.

Extended tensor decomposition model reduction methods: Training, prediction, and design under uncertainty

This paper introduces an extended tensor decomposition (XTD) method for model reduction. The proposed method is based on a sparse non-separated enrichment to the conventional tensor decomposition, which is expected to improve the approximation accuracy and the reducibility (compressibility) in highly nonlinear and singular cases. The proposed XTD method can be a powerful tool for solving nonlinear space–time parametric problems. The method has been successfully applied to parametric elastic–plastic problems and real time additive manufacturing residual stress predictions with uncertainty quantification. Furthermore, a combined XTD-SCA (self-consistent clustering analysis) strategy is presented for multi-scale material modeling, which enables real time multi-scale multi-parametric simulations. The efficiency of the method is demonstrated with comparison to finite element analysis. The proposed method enables a novel framework for fast manufacturing and material design with uncertainties.

A Flow Sensing Device Formed Exclusively by Employing Additive Manufacturing for On-Site Fabrication Aboard a Ship.

This work concerns the design, fabrication, and testing of a novel air-flow sensor employing exclusively additive manufacturing that can be fabricated on-site, aboard a ship, or in a similarly remote area, without relying on external manufacturing facilities. The developed device's principle of operation is based on vortex shedding; its novelty focuses on employing solely additive manufacturing technology, for the manufacturing-in a single process step-of all the sensor's main elements. In more detail, the required flow-shaping housing, the appropriate piezoresistive sensing element, and the electrical interconnection pads are all constructed in a single process step, through standard Fused Deposition Modeling (FDM) 3D technology. Direct communication to the necessary readout circuitry can be easily achieved through standard soldering utilizing the integrated contact pads of the sensor. The prototype was preliminary characterized, validating its proper functionality. Key features of the proposed device are low cost, fast on-site manufacturing of the entire measuring device, robustness, and simplicity, suggesting numerous potential applications in the shipbuilding industry and other industrial sectors.

Elongational flow mixing: A novel innovative approach to elaborate high-performance SBR-based elastomer compounds

Abstract A dominant extensional flow mixing device (Reactor/Elongational Flow MiXer; RMX) was used to prepare styrene-butadiene rubber (SBR)/silica nanocomposites with high physical performances. First, the processing parameters such as the temperature, number of mixing cycles, and sequenced mixing protocol have been optimized. Thereafter, the morphological structure of different compounds was probed using scanning and transmission electron microscopy. The prediction of the flow properties during processing of uncured materials were modeled using the dynamic and capillary rheometry. The thermo-mechanical sweep behavior of the as-prepared silica-filled SBR specimens was also investigated. By comparing with SBR/silica compounds prepared by the internal mixer, it was proven that elongational flow mixing process can not only reduce mixing energy consumption but also make the manufactured parts to have high state of dispersion, excellent viscoelastic properties, high extensional and yield stresses, and high elastic and rubbery moduli. This study highlights the potential of the elongational flow mixing as an innovative processing approach which is compatible with the industrial expectations for the fast manufacturing of high-performance silica and carbon black filled rubber compounds.

Characterization of the Geotechnical Properties of Expansive Soil Improved by Sludge Waste

Recently, a great rise in the population and fast manufacturing processes were noticed. These processes release significant magnitudes of waste. These wastes occupied a notable ground region, generating big issues for the earth and the environment. To enhance the geotechnical properties of fine-grained soil, a sequence of research projects in the lab were conducted to analyze the impacts of adding sludge waste (SW). The tests were done on both natural and mixed soil with SW at various proportions (2%, 4%, 6%, 8%, and 10%) based on the dry mass of the soil used. The experiments conducted focused on consistency, compaction, and shear strength. With the addition of 10% of SW, the values of LL and PI decreased by 29.7% and 38.5%, respectively. Also, with 10% of SW, the values of swelling percent (SP) and swelling pressure (SPR) decreased by 34% and 33%. On the other hand, SW content increase led to the rise in unconfined compressive strength (UCS) of the soil tested from 511kPa to 726kPa with the addition of 10% SW. Based on the findings, it can be confirmed that 10% SW in its natural state is notable for improving fine-grained soil strength and reducing the environmental hazard related to this waste type.

Exigency of Plant-Based Vaccine against COVID-19 Emergence as Pandemic Preparedness.

After two years since the declaration of COVID-19 as a pandemic by the World Health Organization (WHO), more than six million deaths have occurred due to SARS-CoV-2, leading to an unprecedented disruption of the global economy. Fortunately, within a year, a wide range of vaccines, including pathogen-based inactivated and live-attenuated vaccines, replicating and non-replicating vector-based vaccines, nucleic acid (DNA and mRNA)-based vaccines, and protein-based subunit and virus-like particle (VLP)-based vaccines, have been developed to mitigate the severe impacts of the COVID-19 pandemic. These vaccines have proven highly effective in reducing the severity of illness and preventing deaths. However, the availability and supply of COVID-19 vaccines have become an issue due to the prioritization of vaccine distribution in most countries. Additionally, as the virus continues to mutate and spread, questions have arisen regarding the effectiveness of vaccines against new strains of SARS-CoV-2 that can evade host immunity. The urgent need for booster doses to enhance immunity has been recognized. The scarcity of "safe and effective" vaccines has exacerbated global inequalities in terms of vaccine coverage. The development of COVID-19 vaccines has fallen short of the expectations set forth in 2020 and 2021. Furthermore, the equitable distribution of vaccines at the global and national levels remains a challenge, particularly in developing countries. In such circumstances, the exigency of plant virus-based vaccines has become apparent as a means to overcome supply shortages through fast manufacturing processes and to enable quick and convenient distribution to millions of people without the reliance on a cold chain system. Moreover, plant virus-based vaccines have demonstrated both safety and efficacy in eliciting robust cellular immunogenicity against COVID-19 pathogens. This review aims to shed light on the advantages and disadvantages of different types of vaccines developed against SARS-CoV-2 and provide an update on the current status of plant-based vaccines in the fight against the COVID-19 pandemic.

Investigation of Inkjet-Printed Masks for Fast and Easy Photolithographic NIL Masters Manufacturing.

Modern optical systems often require small, optically effective structures that have to be manufactured both precisely and cost-effectively. One option to do this is using nanoimprint lithography (NIL), in which the optical structures are replicated as masters using a stamping process. It would also be advantageous to manufacture the master structures quickly and easily. A master manufacturing process based on a photolithographic image of an inkjet-printed mask is presented and investigated in this paper. An essential element is that a deliberate blurring of the printed structure edge of the mask is used in the photolithographic process. Combined with the use of a non-linear photoresist, this allows for improved edge geometries of the master structure. We discuss the inkjet-printed photomask, the custom photolithography system to prevent imaging of the printing dot roughness and the manufacturing processes of NIL polymer masks as well as their subsequent stamp imprinting. Finally, it was shown that stamp geometries with a width of 1.7 µm could be realised using inkjet-printed photomasks in the master manufacturing process. This methodology opens up the potential of fast and simple master manufacturing for the development and manufacturing of optical elements.

Cyanine dyes grafted onto collagen molecules for 3D printing of fluorescent biological scaffolds

In the photopolymerization 3D printing technology, preparing solid fluorescent biomaterials with fine structure is difficult due to the light barrier, aggregation quenching, and osmotic dissolution caused by adding fluorescent dyes, which severely limits their application in clinical practice. In this study, a bioactive fluorescence dye was prepared by coupling collagen type I and Cyanine IR-780 (Cyan) by dihydrolipoic acid (DHLA), in which 75.0% of primary amine of collagen was coupled with carboxyl of DHLA, and 48.4% of SH was coupled with Cyanine IR-780. The obtained collagen-based dye showed light stability under 405 nm LED light source and can be used in digital light processing-3D printing to fabricate hydrogel scaffolds containing bone collagen with fluorescent properties. The retained SH group in this macromolecular fluorescent dye can participate in the polymerization reaction in the photopolymerization process and improve the photopolymerization speed. With the formation of photopolymerized collagen polymer, the dye molecule shows fluorescence enhancement and antiaggregation caused quenching (anti-ACQ effect). The presented methods provide a foundation for the manufacturing of high-resolution solid 3D printed fluorescent structures, with direct relevance to biomedical optics and the broad adoption of fast manufacturing methods in fluorescence imaging.

A Wavelength Tunable Multi-Section PIC as an Upstream Transmitter for TWDM Networks

In this paper, we demonstrate a novel multi-section directly modulated laser transmitter for upstream operation in the application of time wavelength division multiplexing (TWDM) architecture. The photonic integrated circuit (PIC) is fabricated using a regrowth-free process that favors simplified and fast manufacturing. The PIC is based on a master-slave configuration, with an addition of a variable optical attenuator (VOA) section between them, and a semiconductor optical amplifier (SOA) at the output. The VOA enables control of the optical injection from the master to the directly modulated slave laser improving the transmission performance. The integrated SOA section at the output is used to boost or turn off the optical output power of the transmitter, thereby enabling burst mode operation. Experimental results show that the PIC can be tuned to four wavelength channels on a 100 GHz frequency grid. We also demonstrate that each channel achieves error-free performance (bit error ratio < 10e <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> ), when modulated with 10 Gbps signal and transmitted over 25 km and 50 km fiber. The SOA-based output disable feature of the PIC delivers more than 60 dB attenuation.

An Effective Resistive-Type Alcohol Vapor Sensor Using One-Step Facile Nanoporous Anodic Alumina.

With the increases in work environment regulations restricting alcohol to 1000 ppm, and in drink-driving laws, testing for alcohol with a simple method is a crucial issue. Conventional alcohol sensors based on sulfide, metal oxide, boron nitride or graphene oxide have a detection limit in the range of 50-1000 ppm but have disadvantages of complicated manufacture and longer processing times. A recent portable alcohol meter based on semiconductor material using conductivity or chemistry measurements still has the problem of a complex and lengthy manufacturing process. In this paper, a simple and effective resistive-type alcohol vapor sensor using one-step anodic aluminum oxide (AAO) is proposed. The nanoporous AAO was produced in one-step by anodizing low-purity AA1050 at room temperature of 25 °C, which overcame the traditional high-cost and lengthy process at low temperature of anodization and etching from high-purity aluminum. The highly specific surface area of AAO has benefits for good sensing performance, especially as a humidity or alcohol vapor sensor. With the resistance measurement method, alcohol vapor concentration of 0, 100, 300, 500, 700 and 1000 ppm correspond to mean resistances of 8524 Ω, 8672 Ω, 9121 Ω, 9568 Ω, 10,243 Ω, and 11,045 Ω, respectively, in a linear relationship. Compared with other materials for detecting alcohol vapor, the AAO resistive sensor has advantages of fast and simple manufacturing with good detection limits for practical applications. The resistive-type alcohol vapor-sensing mechanism is described with respect to the resistivity of the test substance and the pore morphology of AAO. In a human breath test, the AAO sensor can quickly distinguish whether the subject is drinking, with normal breath response of -30% to -40% and -20% to -30% response after drinking 50 mL of wine of 25% alcohol.

DLP 4D Printing of Multi‐Responsive Bilayered Structures

AbstractAdvances in soft robotics strongly rely on the development and manufacturing of new responsive soft materials. In particular, light‐based 3D printing techniques, and especially, digital light processing (DLP), offer a versatile platform for the fast manufacturing of complex 3D/4D structures with a high spatial resolution. In this work, DLP all‐printed bilayered structures exhibiting reversible and multi‐responsive behavior are presented for the first time. For this purpose, liquid crystal elastomers (LCEs) are used as active layers and combined with a printable non‐responsive elastomer acting as a passive layer. Furthermore, selective light response is incorporated by embedding various organic dyes absorbing light at different regimes in the active layers. An in‐depth characterization of the single materials and printed bilayers demonstrates a reversible and selective response. Last, the versatility of the approach is shown by DLP printing a bilayered complex 3D structure consisting of four different materials (a passive and three different LCE active materials), which exhibit different actuation patterns when irradiated with different wavelengths of light.

Synthesis and Characteristics of Graphene–Graphene Oxide Material Obtained by an Underwater Impulse Direct Current Discharge

This work proposed a novel approach, in which an impulse underwater discharge was used to produce graphene–graphene oxide material in distilled water. The characteristics of this discharge were presented, including electrical parameters, plasma composition, and electron concentration. Graphene-based material produced using this approach can be evenly dispersed in water without the use of a surfactant or stabilizer, and is suitable for storage at room temperature. Ultraviolet–visible spectroscopy was employed to analyze the optical properties of the graphene-based structures. Scanning electron microscopy was adopted to explore the morphology and size of the particles. The FTIR spectroscopy confirms the formation of graphene oxide. The Raman spectroscopy demonstrates the formation of a graphene-containing multilayer material. The results of this study confirmed that graphene-based material production by impulse underwater discharge is a low-cost, fast, and effective manufacturing method.

A comparative static and dynamic behavior of thermoplastic composite joints produced using different joining techniques

AbstractThermoplastic composites are preferred over their thermosetting counterparts due to their high toughness, fast manufacturing cycle, and ease of recycling. Another advantage is the variety of techniques available to join these thermoplastic composites. This paper analyzes the static and dynamic behavior of glass fiber‐reinforced thermoplastic composite joints produced using different joining techniques. The composite materials were fabricated by compression molding of glass fabric and polypropylene (PP) matrix. These composites were joined using approaches like riveting, adhesive bonding, resistance welding, and hybrid joining techniques. The performance of these joints was analyzed under static and dynamic tensile loads. During the static test, the resistance welded joints showed superior performance as compared to the other joining techniques. The highest load of 2183 N was taken by the resistance welded sample, while the least (358 N) was taken by the mechanical joint. In dynamic testing, the resistance welded joints showed the least variation in the modulus during the dynamic test, showing a higher modulus as compared to the other joining techniques. The highest number of cycles to fail the joint was obtained for the mechanical joint, that is, 40,100, while a similar value was exhibited by the resistance welded joint (39,674). The static and dynamic test results showed resistance welding to be a promising approach for joining thermoplastic composites.

A Study On Mechanical Properties Of 3d Printed Hybrid Polymer Composites

The use of 3D printing has gained significant popularity for producing functional components, ranging from prototypes and membranes to shields and sports wearables. As this method becomes more prevalent, there is a growing need to address challenges related to the limitations of suitable printing materials compared to traditional materials. Innovative methods for simulating failures in 3D-printed cellular structures have been developed to emphasize the impact of various process variables. The scarcity of appropriate printing materials can be attributed to the constraints of 3D printing techniques in accommodating a diverse range of materials. Over the past decade, 3D printing technologies have found extensive application across industries, including the military, serving as a rapid prototyping, and manufacturing method. However, commercially available printing polymers have exhibited inherently lower mechanical properties, such as strength and stiffness, when compared to traditional manufacturing materials. To overcome these limitations, multi-material additive manufacturing (AM) technology has emerged as a promising alternative. This approach allows for the creation of complex structures with a broad spectrum of mechanical characteristics, presenting a significant advancement over traditional assembly methods. In ongoing efforts to enhance material qualities, there is a current focus on fabricating polymer composites using 3D printing techniques. Various reinforcement materials, including carbon fibers and multi-walled carbon nanotubes (MCNTs), are being incorporated into matrix materials like ABS and PETG. This endeavor aims to exploit the capabilities of 3D printers to innovate and create complex items with improved material properties, opening the door to further research and development in fast manufacturing processes.

Feasibility study on electrically conductive joining of MoSi2 electrodes for spark plugs

AbstractDespite the often outstanding functional as well as (high temperature‐) mechanical properties of ceramics, their usage is often limited due to their inherent brittleness. This also compromises the joining with metals, which is often indispensable for engineering applications. In this context, electrically conductive ceramics like MoSi2 are promising materials for the application as electrodes where high temperatures in harsh environments are present (e.g., in spark plugs for large gas engines). Due to the difficult joining of the respective materials, long‐term experiments are thereby often still pending. In this work, adhesive bonding, brazing, tungsten inert gas‐, and resistance welding were performed to evaluate their applicability for generating electrically conductive as well as mechanically reliable joints between MoSi2 and Inconel 600, aiming to utilize MoSi2 electrodes in spark plugs. Fractographic analyses are performed to understand cracks associated with the high (thermo‐) mechanical stresses. Additionally, a finite element model was set up for a deeper understanding of the observed fracture behavior. While adhesive bonding is acceptable for short‐term experiments at low temperatures, brazing and resistance welding may qualify for fast and reliable manufacturing of spark plugs with ceramic electrodes.

Effect of Extruder Type in the Interface of PLA Layers in FDM Printers: Filament Extruder Versus Direct Pellet Extruder.

FDM (Fused Deposition Modeling) is one of the most used and industrially applied additive manufacturing processes due to its fast prototyping and manufacturing, simplicity, and low cost of the equipment. However, the mechanical properties of the printed products have a large dependence on orientation and interface strength between layers which is mainly related to the thermal union obtained. This thermal union has a large dependence on the melting and cooling down process. Additionally, the materials used must be extruded in a continuous filament before their use, which limits the materials used. However, a pellet extruder could be used directly in the printing equipment, avoiding filament extrusion. In this work, specimens of PLA (Poly(lactic acid)) with different bead orientations have been produced via filament or pellet extrusion to compare the effect of the different melting processes in the manufacturing methodology. Pellet extruded specimens showed higher infill and mechanical properties. These results were related to better adhesion between layers due to the longer melting and cooling process. The result was confirmed using DSC and XRD techniques, where a higher crystallinity was observed. A bicomponent specimen (50% pellet-50% filament) was prepared and tested, showing higher mechanical results than expected, which was, again, due to the better thermal union obtained in the pellet extruder.