Object Manufacturing Research Articles

Selective laser melting of partially amorphous regolith analog for ISRU lunar applications

As the idea of crewed outposts on the Moon gains momentum, In-Situ Resource Utilization (ISRU) technologies tend to become imperative to fulfill astronauts' needs. This article explores a way to use the lunar regolith as a source material for the additive manufacturing of complex objects, based on the selective laser melting (SLM) technique. A lunar regolith analog, Basalt of Pic d’Ysson (BPY), is used as a starting point for this study, to investigate the now demonstrated impact of amorphous analog content in the powder bed, substrate type, and post-SLM annealing treatments on the mechanical properties of 3D-printed objects. Improvements to the manufacturing and sample extraction stages are proposed to systematically reproduce the high compressive strength values obtained, thus contributing to the robustness and reliability of the process.

Simultaneous Color- and Dose-Controlled Thiol-Ene Resins for Multimodulus 3D Printing with Programmable Interfacial Gradients.

Drawing inspiration from nature's own intricate designs, synthetic multimaterial structures have the potential to offer properties and functionality that exceed those of the individual components. However, several contemporary hurdles, from a lack of efficient chemistries to processing constraints, preclude the rapid and precise manufacturing of such materials. Herein, the development of a photocurable resin comprising color-selective initiators is reported, triggering disparate polymerization mechanisms between acrylate and thiol functionality. Exposure of the resin to UV light (365nm) leads to the formation of a rigid, highly crosslinked network via a radical chain-growth mechanism, while violet light (405nm) forms a soft, lightly crosslinked network via an anionic step-growth mechanism. The efficient photocurable resin is employed in multicolor digital light processing 3D printing to provide structures with moduli spanning over two orders of magnitude. Furthermore, local intensity (i.e., grayscale) control enables the formation of programmable stiffness gradients with ≈150× change in modulus occurring across sharp (≈200µm) and shallow (≈9mm) interfaces, mimetic of the human knee entheses and squid beaks, respectively. This study provides composition-processing-property relationships to inform advanced manufacturing of next-generation multimaterial objects having a myriad of applications from healthcare to education.

Genetic Algorithm-Based Data-Driven Process Selection System for Additive Manufacturing in Industry 4.0.

Additive manufacturing (AM) has impacted the manufacturing of complex three-dimensional objects in multiple materials for a wide array of applications. However, additive manufacturing, as an upcoming field, lacks automated and specific design rules for different AM processes. Moreover, the selection of specific AM processes for different geometries requires expert knowledge, which is difficult to replicate. An automated and data-driven system is needed that can capture the AM expert knowledge base and apply it to 3D-printed parts to avoid manufacturability issues. This research aims to develop a data-driven system for AM process selection within the design for additive manufacturing (DFAM) framework for Industry 4.0. A Genetic and Evolutionary Feature Weighting technique was optimized using 3D CAD data as an input to identify the optimal AM technique based on several requirements and constraints. A two-stage model was developed wherein the stage 1 model displayed average accuracies of 70% and the stage 2 model showed higher average accuracies of up to 97.33% based on quantitative feature labeling and augmentation of the datasets. The steady-state genetic algorithm (SSGA) was determined to be the most effective algorithm after benchmarking against estimation of distribution algorithm (EDA) and particle swarm optimization (PSO) algorithms, respectively. The output of this system leads to the identification of optimal AM processes for manufacturing 3D objects. This paper presents an automated design for an additive manufacturing system that is accurate and can be extended to other 3D-printing processes.

Strontium isotopes and cremation: Investigating mobility patterns in the Roman city of Mutina (north-eastern Italy)

Cremation was a very common ritual in ancient Roman funerary traditions. However, the study of cremated human remains has always been complex and challenging, which has often led to an imbalance in data recording between inhumations and cremations. In this work, we study 14 cremation burials from two different urban cemeteries in the Roman city of Mutina (Modena, Emilia-Romagna, north-eastern Italy). The use of strontium isotope analysis provides insights into the mobility pattern and provenance of individuals cremated and buried at Mutina. The isotopic results suggest that nine samples fall outside the local bioavailable strontium range of the city of Modena, given their different 87Sr/86Sr values compared to the ratio compatible with alluvial deposits in the Po Valley. Both the isotopic results and the manufacture of some funerary objects suggest that the probable provenance of some individuals is compatible with western (Pre)Alpine areas. The values of 87Sr/86Sr also complement the results obtained from the osteological analysis increasing the minimum number of individuals buried in at least one grave. Our study revealed key insights about cremated individuals from Italy, highlighting variations of the mobility patterns within Roman funerary contexts of Mutina.

Pemanfaatan Penambahan Limbah Inner-Tube Rubber dan Penggunaan Abu Cangkang Kemiri Sebagai Substitusi Filler pada Campuran AC-WC

Various problems that occur in asphalt damage in Indonesia have triggered new innovations to deal with existing problems, one of which is by improving the quality of asphalt by adding substances (additives) or substitutions to the aggregate composition. This study aims to determine the utilization of inner tube rubber waste and the use of candlenut shell ash as a substitute filler in the AC-WC mixture. This study is an experimental study. The manufacture of test objects using an AC-WC mixture with a total of 18 test objects was then tested using the Marshall method. The results of this study indicate that the use of inner-tube rubber waste and candlenut shell ash greatly affects the Marshall parameter value. With an Optimum Asphalt Content of 6%, the best variation content was obtained at 3% of inner tire rubber additives and 25% substitution of candlenut shell ash as filler with a density value of 2.341 gr/cm3, VMA 15.50%, VIM 4.36%, VFA 71.87%, stability 1730.79 kg, flow 3.36 mm and MQ 565.01 kg/mm ​​which meets the 2018 Bina Marga Specifications Revision 2.

Nanoporous, Ultrastiff, and Transparent Plastic-like Polymer Hydrogels Enabled by Hydrogen Bonding-Induced Self-Assembly.

Most natural supporting tissues possess both exceptional mechanical strength, a significant amount of water, and the anisotropic structure, as well as nanoscale assembly. These properties are essential for biological processes, but have been challenging to emulate in synthetic materials. In an effort to achieve simultaneous improvement of these trade-off features, a hydrogen bonding-induced self-assembly strategy was introduced to create nanoporous plastic-like polymer hydrogels. Multiple hydrogen bonding-mediated networks and nanoporous orientation structures endow transparent hydrogels with remarkable mechanical robustness. They exhibit Young's modulus of up to 223.7 MPa and a breaking strength of up to 10.3 MPa, which are superior to those of most common polymer hydrogels. The uniform porous nanostructures of hydrogen-bonded hydrogels contribute to a significantly larger specific surface area compared to conventional hydrogels. This allows for the retention of high mechanical properties in environments with a high water content of 70 wt %. A rubbery stage is observed during the heating process, which can reverse and reshape the manufacture of objects with various desired 2D or 3D shapes using techniques such as origami and kirigami. Finally, as a proof-of-concept, the outstanding mechanical properties of poly(MAA-co-AA-co-NVCL) hydrogel, combined with its high water content, make it suitable for applications such as smart temperature monitors, multilevel information anticounterfeiting, and artificial muscles.

Experimental and FEA Simulations Using ANSYS on the Mechanical Properties of Laminated Object Manufacturing (LOM) 3D-Printed Woven Jute Fiber-Reinforced PLA Laminates

The mechanical properties of woven jute fiber-reinforced PLA polymer laminates additively manufactured through Laminated Object Manufacturing (LOM) technology are simulated using the finite element method in this work. Woven jute fiber reinforcements are used to strengthen bio-thermoplastic PLA polymers in creating highly biodegradable composite structures that can serve as one of the environmentally friendly alternatives for synthetic composites. A LOM 3D printer prototype was designed and built by the authors. All woven jute/PLA biocomposite laminated specimens made using the built prototype in this study had their tensile and flexural properties measured using ASTM test standards. These laminated structures were modeled using the ANSYS Mechanical Composite PrepPost (ACP) module, and then both testing processes were simulated using the experimentally measured input values. The FEA simulation results indicated a close match with experimental results, with a maximum difference of 9.18%. This study served as an exemplary case study using the FEA method to predict the mechanical behaviors of biocomposite laminate materials made through a novel manufacturing process.

Influence of oscillatory hydromagnetic field with mixed convection driven Sutterby nanofluid flow over a stretching cylinder

A nonlinear mixed convective sutterby nanofluid flow along a stretching cylinder is being studied in this article. The set of partial differential equations (PDEs) that control fluid flow is nonlinear and subject to surface constraints and similarity transformation reduces a system of PDEs to non-dimensional ordinary differential equations (ODEs), which are then solved in MATLAB Bvp5c solver which is based on the Runge–Kutta method and Shooting technique. We provide a graphic evaluation of the significant contributions made by the various physical terms to engineering measurements in the curiosity and transport domains. The study discovers that temperature distribution increases heat border viscosity but reduces thermal diffusion, whereas nonlinear convection heat improves surface heat transfer. The periodic magnetic field raises the fluid temperature while decreasing the rate of energy transfer. Furthermore, experiments have demonstrated that oscillating magnetic fields induce fluctuations with a sinusoidal pattern. Furthermore, the current study has applications in the design and manufacture of cylinder-shaped objects in various fields such as aerospace engineering, geophysics, and nuclear engineering. These include core catchers in nuclear power plant steam turbines, waxy crude oils or foodstuffs in centrifugal pumps, and deformation rates that frequently occur in practical turbomachinery and other industrial processes.

Mechanical property characterizations of woven natural fiber-reinforced polymers 3D printed through a laminated object manufacturing process

ABSTRACT The mechanical properties of woven natural fiber reinforced polymers additively manufactured through Laminated Object Manufacturing (LOM) technology are investigated in this paper. The benefits of both the material and manufacturing process were combined into a sustainable practice, as a potential alternative to traditional synthetic composite materials made from nonrenewable crude oil with limited end-of-life alternatives. Woven jute fiber reinforcements are used to strengthen both synthetic and bio- thermoplastic polymers in creating highly biodegradable composite structures. Such materials, as one of the prospective alternatives for synthetic composites, can be used in many engineering fields such as automobile panels, construction materials, and commodity and recreational products including sports and musical instruments. A LOM 3D printer prototype was designed and built by the authors. All woven jute/polymer biocomposite test specimens made using the built prototype in this study had their mechanical (both tensile and flexural) properties assessed using ASTM test standards and then compared to similar values measured from pure polymer specimens. Improved mechanical characteristics were identified and analyzed. Finally, SEM imaging was performed to identify the polymer infusion and fiber-matrix bonding conditions.

Additive Manufacturing: A Comprehensive Review.

Additive manufacturing has revolutionized manufacturing across a spectrum of industries by enabling the production of complex geometries with unparalleled customization and reduced waste. Beginning as a rapid prototyping tool, additive manufacturing has matured into a comprehensive manufacturing solution, embracing a wide range of materials, such as polymers, metals, ceramics, and composites. This paper delves into the workflow of additive manufacturing, encompassing design, modeling, slicing, printing, and post-processing. Various additive manufacturing technologies are explored, including material extrusion, VAT polymerization, material jetting, binder jetting, selective laser sintering, selective laser melting, direct metal laser sintering, electron beam melting, multi-jet fusion, direct energy deposition, carbon fiber reinforced, laminated object manufacturing, and more, discussing their principles, advantages, disadvantages, material compatibilities, applications, and developing trends. Additionally, the future of additive manufacturing is projected, highlighting potential advancements in 3D bioprinting, 3D food printing, large-scale 3D printing, 4D printing, and AI-based additive manufacturing. This comprehensive survey aims to underscore the transformative impact of additive manufacturing on global manufacturing, emphasizing ongoing challenges and the promising horizon of innovations that could further elevate its role in the manufacturing revolution.

Interrelations between Printing Patterns and Residual Stress in Fused Deposition Modelling for the 4D Printing of Acrylonitrile Butadiene Styrene and Wood–Plastic Composites

Four dimensional printing enables the advanced manufacturing of smart objects that can morph and adapt shape over time in response to stimuli such as heat. This study presents a single-material 4D printing workflow which explores the residual stress and anisotropy arising from the fused deposition modelling (FDM) printing process to create heat-triggered self-morphing objects. In particular, the study first investigates the effect of printing patterns on the residual stress of FDM-printed acrylonitrile butadiene styrene (ABS) products. Through finite element analysis, the raster angle of printing patterns was identified as the key parameter influencing the distribution of residual stresses. Experimental investigations further reveal that the non-uniform distribution of residual stress results in the anisotropic thermal deformation of printed materials. Thus, through the design of printing patterns, FDM-printed materials can be programmed with desired built-in residual stresses and anisotropic behaviours for initiating and controlling the transformation of 4D-printed objects. Using the proposed approach, any desktop FDM printers can be turned into 4D printers to create smart objects that can self-morph into target geometries. A series of 4D printing prototypes manufactured from conventional ABS 3D printing feedstock are tested to illustrate the use and reliability of this new workflow. Additionally, the custom-made wood–plastic composite (WPC) feedstocks are explored in this study to demonstrate the transposability of the 4D printing approach.

Mechanical properties of additively manufactured polymeric composites using sheet lamination technique and fused deposition modeling: A review

AbstractNowadays, it is possible to produce products with complex geometries, thanks to the experts who have continuously explored the advancements in additive manufacturing (AM) techniques. This review helps readers understand the opportunities and difficulties associated with developing parts for various industries, including aerospace, tooling, electronics, and biomedicine. The present work describes the landscape of polymeric composites using laminated object manufacturing (LOM) and fused deposition modeling (FDM). This paper discusses recent publications in the realm of AM related to composite fabrication, materials, techniques, functionality, and future scope. The effects of nanofiller reinforcement on the mechanical properties of composites have been thoroughly investigated. Furthermore, FDM process parameters such as layer thickness, infill speed, nozzle temperature, and raster angle have also been considered. Finally, the challenges and potential applications of LOM and FDM of additively manufactured composites have been summarized.

Full-Combinatorial Concentration Gradient Array with 3D Micro/Nanofluidics for Antibiotic Susceptibility Testing.

Recent advancements in micro/nanofluidics have facilitated on-chip microscopy of cellular responses in a high-throughput and controlled microenvironment with the desired physicochemical properties. Despite its potential benefits to combination drug discovery, generating a complete combinatorial set of concentration gradients for multiple reagents in an array format remains challenging. The main reason is limited layouts of conventional micro/nanofluidic systems based on two-dimensional channel networks. In this paper, we present a device with three-dimensional (3D) interconnection of micro/nanochannels capable of generating a complete combinatorial set of concentration gradients for two reagents. The device was readily fabricated by laminating a pair of multilayered monolithic films containing a Christmas tree-like mixer, a cell culture chamber array, and through-holes, all within each single film. We assessed the reliable generation of a full-combinatorial concentration gradient array and validated it by using numerical analysis. We applied the proposed device to test the antibiotic susceptibility of bacterial cells in a convenient one-step manner. Furthermore, we explored the potential of the device to accommodate the arrayed complete combinatorial set for two or more drugs, while extending the capabilities of our laminated object manufacturing method for realizing 3D micro/nanofluidic systems.

Synthesis and Characterisation of 4D-Printed NVCL-co-DEGDA Resin Using Stereolithography 3D Printing

The design and manufacturing of objects in various industries have been fundamentally altered by the introduction of D-dimensional (3D) and four-dimensional (4D) printing technologies. Four-dimensional printing, a relatively new technique, has emerged as a result of the ongoing development and advancements in 3D printing. In this study, a stimulus-responsive material, N-Vinylcaprolactam-co-DEGDA (NVCL-co-DEGDA) resin, was synthesised by Stereolithography (SLA) 3D printing technique. The N-Vinylcaprolactam-co-DEGDA resins were initiated by the Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiator. A range of Di(ethylene glycol) diacrylate (DEGDA) concentrations in the NVCL-co-DEGDA resin was explored, ranging from 5 wt% to 40 wt%. The structural properties of the 3D printed objects were investigated by conducting Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the 3D printed samples underwent further characterisation through differential scanning calorimetry (DSC) and swelling analysis. The results revealed an inverse relationship between DEGDA concentration and Tg values, indicating that higher concentrations of DEGDA resulted in lower Tg values. Additionally, the pulsatile swelling studies demonstrated that increasing DEGDA concentration prolonged the time required to reach the maximum swelling ratio. These findings highlight the influence of DEGDA concentration on both the thermal properties and swelling behaviour of 3D printed samples.

Movement Strategy Influences on the Characteristics of Low-Carbon Steel Generated by the Lamination Object Manufacturing Method

This paper investigates the effects of heating movement techniques on the properties of low-carbon steel samples that are 3D printed using S20C lamination object manufacturing (LOM). A Tungsten iner gas (TIG) machine and a computer numerical control (CNC) machine were used together to join the steel sheet. The LOM samples were created with a straight-profile, short-profile, cross-profile, and curved-profile. The results indicate that the majority of the samples had a grain size number of 7–9. The samples exhibited an isotropy grain shape. The LOM samples exhibited dimples, which suggests ductility fractures. Pore flaws showed up in the microstructure of the cross-profile and short-profile samples during the LOM process. The samples with curved- and straight-profiles had a better microstructure. In comparison to samples with a short profile and a cross-profile, the samples with a straight-profile and a curved-profile had a superior combination of ultimate tensile strengths (UTSs) and elongation value. The straight- and curved-profiles’ greater elongation and tensile strength can be attributed to their improved microstructure and finer grain size. A straight-profile sample with an elongation value of 25.6% and a UTS value of 430 MPa was the ideal LOM sample. Conversely, the weakest sample was the LOM sample with a cross-profile, which had an elongation value of 10.8% and a UTS value of 332.5 MPa. This research could provide further information about the LOM method and the best straight-profile movement strategy. A suitable TIG gun movement strategy could produce a good LOM sample with a good microstructure, tensile strength, and ductility. Further research should incorporate more movement strategies and techniques that completely prevent the formation of pore defects.

Pemanfaatan Limbah Plastik Sebagai Bahan Campuran Aspal Pada Perkerasan Aspal AC-WC Dengan Perendaman Air Tawar Dan Air Laut Secara Berulang

Asphalt is a cementitious material, dark or dark brown pattern, with the main factor of bitumen obtained from petroleum refining residues acting as an aggregate binder in road making. The purpose of this research is to determine the effect of increasing LDPE on Marshall's characteristics in asphalt mixtures with repeated immersion. This study used LDPE plastic waste with an accumulation of 10%, 15%, and 20%. The test item samples were made of 27 variation samples. Treatment of test items was tried with repeated soaking variations of 3, 7, as well as 10 days. The manufacture of test objects is mixed hotly and refers to the 2018 Bina Marga Specifications. Testing was tried with Marshall test kits. The results of this test show that the influence of LDPE plastic waste as an added material on asphalt mixture with repeated immersion can cause density, stability, MQ, and VFB values to shrink. On the contrary, the value of flow, VMA, and VIM increases.

Electrically Conductive Polymers for Additive Manufacturing.

The use of electrically conductive polymers (CPs) in the development of electronic devices has attracted significant interest due to their unique intrinsic properties, which result from the synergistic combination of physicochemical properties in conventional polymers with the electronic properties of metals or semiconductors. Most conventional methods adopted for the fabrication of devices with nonplanar morphologies are still challenged by the poor ionic/electronic mobility of end products. Additive manufacturing (AM) brings about exciting prospects to the realm of CPs by enabling greater design freedom, more elaborate structures, quicker prototyping, relatively low cost, and more environmentally friendly electronic device creation. A growing variety of AM technologies are becoming available for three-dimensional (3D) printing of conductive devices, i.e., vat photopolymerization (VP), material extrusion (ME), powder bed fusion (PBF), material jetting (MJ), and lamination object manufacturing (LOM). In this review, we provide an overview of the recent research progress in the area of CPs developed for AM, which advances the design and development of future electronic devices. We consider different AM techniques, vis-à-vis, their development progress and respective challenges in printing CPs. We also discuss the material requirements and notable advances in 3D printing of CPs, as well as their potential electronic applications including wearable electronics, sensors, energy storage and conversion devices, etc. This review concludes with an outlook on AM of CPs.

THE CABINET OF MINISTERS AS A SUBJECT OF THE LAW-MAKING PROCESS: PROBLEMS AND SOLUTIONS IN LEGISLATION

This article talks about the powers of the Cabinet of Ministers in the field of lawmaking and its role in legislation, analyzes the definitions of legislative activity, explains the powers of the Cabinet of Ministers, its connection with other legislative processes. Manufacturing of objects and its features. It is substantiated that the law-making activity of the central collegial executive body occupies a special place in the national legal system, based on the position and legal status of this entity in the system of state bodies. In addition, the author’s definitions of such concepts as legislative activity and legislative activity of the Cabinet of Ministers are given, various aspects of resolutions and orders of the Cabinet of Ministers of the Republic of Uzbekistan are shown. It is concluded that although the resolutions of the Cabinet of Ministers are not aimed at establishing, amending or repealing a new legal norm, they determine the official regulation of one or another type of social relations by the state. In addition to the above, based on an analysis of the norms of the Law of the Republic of Uzbekistan “On Regulatory Legal Acts”, “On the Cabinet of Ministers of the Republic of Uzbekistan”, proposals have been put forward to introduce relevant norms into Articles 36 and 37 of the Law “On the Cabinet of Ministers of the Republic of Uzbekistan” and into the “Regulations of the Cabinet Ministers of the Republic of Uzbekistan".

3D printing, modelling and simulation for dental implant: A comprehensive review

The implementation of three-dimensional printing technology has revolutionised dentistry over the past decade. The desired object is scanned by a 3D scanner or built using computer-aided design (CAD)/computer-aided manufacturing (CAM) software. CAD designs of dental implants can be analysed by the finite element method (FEM). Finite element analysis (FEA) is done by discretising the geometrically developed model into smaller and simpler elements and analysing the 3D model using different boundary conditions on different nodes. Depending on the materials of choice, various printing methods are available, such as selective laser sintering (SLS), stereolithography, fused deposition modelling, and laminated object manufacturing. Dental implants are designed with the help of different biomaterials, such as polymers, metals, and ceramics. Clinicians should know the latest implant materials for successful implant therapy. This review article investigates 3D printing on various dental implants, designs, simulations, and limitations. The last part of the article discusses different properties of the implant materials used in the designs.

Re-examining the Key Issues Concerning the Craftworks Uncovered from Tonggung Palace and Wŏlchi Pond in Kyŏngju

The excavation of Wŏlchi pond in Kyŏngju has yielded numerous craftworks that offer crucial information about Silla’s crafts. However, due to damage or missing parts, it is difficult to fully understand the nature of some items. Additionally, there are some findings whose appearance and conditions at the time of discovery remain unidentifiable. Therefore, over 50 years since the initial excavation in 1975, it is necessary to re-examine the current key issues and discuss the future directions of studies concerning the discoveries from Tonggung Palace and Wŏlchi pond. Firstly, I examined specific shapes and production techniques that are only observed in the findings from Wŏlchi pond. Further, I investigated the usage, and manufacture and decorative techniques of crystals and various objects made of bone and horn produced in Kyŏngju. I proposed the correct function of the <i>Lacquered Flower-shaped Ornament</i> as a portable shrine and additionally presented the <i>Gilt-Bronze Wick Trimmer</i>, suitably made for its role, as evidence of the new culture involving candles. When further research is conducted into the uses, production techniques, and decorative designs of the items found in incomplete form, such as <i>Bamboo-shaped Ornament, Bone Fragment with Flower and Bird Design</i>, and <i>Lacquered Plate with Flower and Foliage Design</i>, we may be able to understand more aspects of the craft culture of Unified Silla. Furthermore, the recovered items from Wŏlchi pond exhibiting various designs, such as birds holding flowers in their beaks (<i>hamjomun</i>), flower medallions (<i>bosanghwamun</i>), and rows of beads (<i>yeonjumun</i>), provide evidence that Unified Silla shared a common decorative trend with Tang China and Nara Japan. Tonggung palace and Wŏlchi pond are valuable resources for the history of decorative patterns in Korea.