Rapid Manufacturing Research Articles

Considerations in Acquisition of 3D-Printed Art

ABSTRACT 3D printing (also known as Rapid Prototyping or Additive Manufacture) is increasingly common and technically sophisticated, and is utilized in art and design, industry, and consumer applications. Museums and collectors are now acquiring works made using this technology though their preservation needs are not fully understood. This article provides an overview of the technology and related terminology, review of related conservation literature, and introduction to current efforts for the care of these works. Discussion includes the formulation of collaborative working practices, documentation during acquisition, and consideration of periodic reprinting. Case studies include a pre-accession checklist developed at SFMOMA (San Francisco Museum of Modern Art) and the reprinting of select components from Altar/Engine (2015) by Tauba Auerbach at MoMA (Museum of Modern Art) in New York. Though 3D-printed works may be found in science, history, and other collections, this study will focus on works of contemporary art and design.

Impact of the 100 days mission for vaccines on COVID-19: a mathematical modelling study

The COVID-19 pandemic has underscored the beneficial impact of vaccines. It also highlighted the need for future investments to expedite an equitable vaccine distribution. The 100 Days Mission aims to develop and make available a new vaccine against a future pathogen with pandemic potential within 100 days of that pathogen threat being recognised. We assessed the value of this mission by estimating the impact that it could have had on the COVID-19 pandemic. Using a previously published model of SARS-CoV-2 transmission dynamics fitted to excess mortality during the COVID-19 pandemic, we projected scenarios for three different investment strategies: rapid development and manufacture of a vaccine, increasing manufacturing capacity to eliminate supply constraints, and strengthening health systems to enable faster vaccine roll-outs and global equity. Each scenario was compared against the observed COVID-19 pandemic to estimate the public health and health-economic impacts of each scenario. If countries implemented non-pharmaceutical interventions (NPIs) as they did historically, the 100 Days Mission could have averted an estimated 8·33 million deaths (95% credible interval [CrI] 7·70-8·68) globally, mostly in lower-middle income countries. This corresponds to a monetary saving of US$14·35 trillion (95% CrI 12·96-17·87) based on the value of statistical life-years saved. Investment in manufacturing and health systems further increases deaths averted to 11·01 million (95% CrI 10·60-11·49). Under an alternative scenario whereby NPIs are lifted earlier on the basis of vaccine coverage, the 100 Days Mission alone could have reduced restrictions by 12 600 days (95% CrI 12 300-13 100) globally while still averting 5·76 million deaths (95% CrI 4·91-6·81). Our findings show the value of the 100 Days Mission and how these can be amplified through improvements in manufacturing and health systems equity. However, these investments must be enhanced by prioritising a more equitable global vaccine distribution. Schmidt Science Fellowship in partnership with the Rhodes Trust, WHO, UK Medical Research Council, Coalition for Epidemic Preparedness Innovations.

Low-cost fabrication of digital light processing 3D printed conical microneedles for biomedical applications

The 3D printing of microneedles has become an emerging area of research focus due to its ability to rapidly create microneedle arrays with parametrically variable geometry and composition. Through direct fabrication or via replica molding, 3D printed microneedles can facilitate iterative array assessment and act as a screening tool to quickly establish optimal parameters for tissue insertion and capacity for biomarker monitoring or drug release. However, the widespread adoption of 3D printing by microneedle array researcher group faces multiple barriers: (1) Investment in 3D printing systems that are traditionally associated with high-resolution pose a significant financial cost, (2) Current high-resolution printing methods are often slow and not conducive to rapid manufacturing, (3) Material selection can be limited in some ‘proprietary’ 3D printing systems (e.g. CLIP, SLA, or 2PP), (4) Given the multidisciplinary nature of the microneedle-field, researchers may not have the expertise to optimize printing parameters for a given material or printer. This work explores how ultra-low-cost digital light processing (DLP) printers can rapidly produce functional microneedle arrays for a variety of purposes, whether direct print, master mold production, or creation of coated microneedles, at a fraction of the cost of currently used systems. Further, this work highlights that high quality microneedle arrays can be created using DLP printing methods with reliability exceeding 98 %, tip radii on the order of 30 µm, and with appropriate parameter input optimization, high quality microneedle arrays can be fabricated that express desirable characteristics for multiple forms of solid microneedle array production.

3D-printed microfluidic and millifluidic devices for cell culture and mechanotransduction studies: A review

The practice of conventional cell culture techniques affects the quality of biological research in mechanobiology by not replicating the cell’s microenvironment adequately. Microfluidic devices resembling 3D in vivo cell culture offer viable alternatives for mechanobiology studies and other applications including cell screening, cell separation, and point-of-care diagnostics. This review highlights recent advances in additive manufacturing (AM) to fabricate microfluidic and millifluidic devices through fast design iterations and cost reduction compared with conventional device manufacturing. Key advances in AM technologies such as fused deposition modeling (FDM), stereolithography apparatus (SLA), and digital light processing (DLP) have allowed the direct manufacture of complex microfluidic devices with master molds and sacrificial structures using multiple material components. Currently, available 3D printed devices for the precise fabrication of milli- and microfluidic devices, essential to mimicking the cellular microenvironment, while economically reducing production costs by eliminating expensive clean-room environments and reducing material waste are highlighted.

Grain refinement of Inconel 625 during wire-based directed energy deposition additive manufacturing by in-situ added TiB2 particles: Process development, microstructure evolution and mechanical characterization

In this study, a novel method for enhancing the quality of components fabricated by wire and arc additive manufacturing (WAAM) was developed. This approach employs an innovative mechanism featuring an actuator that dispenses a solution containing refinement particles (TiB2 inoculants), in conjunction with a soldering flux that vaporizes prior to reaching the electric arc. This leaves the particles to adhere to the welding wire or be carried by the shielding gas. By implementing this device, TiB2 particles were successfully incorporated into the molten pool during the WAAM process of Inconel 625 at levels of 0.31 and 0.56 wt%. Microstructural analysis reveals a significant reduction in the size of interdendritic segregation regions when TiB2 particles are introduced. Electron backscatter diffraction analysis further reveals the transformation of columnar grains into equiaxed grains. The average grain area decreased from 1823 μm2 in the as-built sample to 583 μm2 in the sample with a TiB2 content of 0.56 wt%. In addition, an improvement in the Inconel 625 fabricated by WAAM mechanical strength was observed due to the use of TiB2 inoculants, which was primarily attributed to the effect of the grain size refinement.

Integrated substrate and adsorbent layer additive manufacturing for asymmetrically operating minichannel adsorbent bed

Adsorption heat pumps (AHP) have conventionally used packed bed design, making their operation sluggish leading to difficulty in using heat for the adsorbent regeneration. While thin adsorbent coatings improve the performance of AHPs when implemented in microscale geometries like minichannels, integrating the adsorbent coating procedure into the scaled-up adsorbent bed manufacturing has been impractical because of the finite time required for the coating process. Meanwhile, separately coated plates manifest sealing issues. This research details an innovative avenue to fabricate a unified adsorbent bed integrated with thin adsorbent coatings. Here, a compact adsorbent bed was fabricated through the integration of additive manufacturing using a fused deposition modeling (FDM) 3D printer for the substrate and resin curing for the MIL-101 (Cr) adsorbent layer. The multi-layered bed was designed to exchange heat between heat transfer fluid (HTF) and the passages through which the refrigerant vapor flows. The vapor channels were coated with a MIL-101 (Cr) adsorbent. The research incorporated both experiments and computational models to evaluate the operation of this adsorbent bed through the measurement of pressure during the adsorption and desorption stages for this component. Various HTF temperatures (80 °C − 90 °C) and flow rates (0.125 kg min−1 – 0.25 kg min -1) were tested. The findings revealed the much-desired asymmetrical operation with long adsorption (75–80 % of the cycle time) and short desorption stages (20 %-25 % of the cycle time), opening the possibility of employing a single bed in adsorption cooling systems to produce a near continuous cooling effect leading to more compact AHPs. The computational model developed for this test setup using MATLAB strongly aligned with experimental findings, with an error margin of 4–12 %.

Fabrication of ultra-high strength MWCNTs/CI /PI rigid composite foam with excellent microwave absorption performance by pressure foaming method

Polyimide (PI) foam exhibits excellent high-temperature resistance and outstanding physical and chemical stability, making it an ideal matrix for absorbing materials. However, the growing demand for absorbing materials that can serve as load-bearing components has revealed that existing polyimide composite foams often fall short of practical application requirements due to their low mechanical properties. The study employed a simple foaming method using isocyanate-based polyimide as the foam base under a 0.2 MPa atm. Multi-walled carbon nanotubes (MWCNTs) and carbonyl iron (CI) powder were added sequentially to the precursor solution. Under the filling parameters of 2.0 % MWCNTs and 10 % CI powder, the compressive strength of polyimide composite foam reaches 16.2 MPa and exhibits excellent microwave absorption properties, with a minimum reflection loss (RLmin) of −62.51 dB and an effective absorption bandwidth (EAB) of 7.86 GHz. Additionally, the prepared composite foam has potential infrared stealth capability. This work offers new insights for rapid and low-cost manufacturing of high-strength absorbing foam.

Minimally invasive detection of buprenorphine using a carbon-coated 3D-printed microneedle array.

Amachine learning-assisted 3D-printed conducting microneedle-based electrochemical sensing platformwas developed for wireless, efficient, economical, and selective determination of buprenorphine. The developed microneedle array-based sensing platform used 3D printing and air spray coating technologies for rapid and scalable manufacturing of a conducting microneedle surface. Upon optimization and understanding of the electrode stability, redox behavior, and electrochemical characteristics of as-prepared conducting microneedle array, the developed electrochemical platform was investigated for monitoring different levels of buprenorphine in the artificial intestinal fluid and found to be highly sensitive and selective towards buprenorphine for a wide detection range from 2 to 140μM, with a low limit of detection of 0.129μM. Furthermore, to make the sensing platform user accessible, the experimentally recorded sensing data was used to train a machine learning model and develop a web application for the numerical demonstration of buprenorphine levels at the point of site. Finally, the proof-of-concept study demonstrated that by advancing our prevailing 3D printing and additive manufacturing techniques, a low-cost, user-accessible, and compelling wearable electrochemical sensor could be manufactured for minimally invasive determination of buprenorphine in interstitial fluid.

A new path planning strategy driven by geometric features and tensile properties for 3D printing of continuous fiber reinforced thermoplastic composites

Three-dimensional (3D) printing technology for continuous fiber reinforced thermoplastic composites (C-FRTP), capable of rapid manufacturing of lightweight components with intricate geometric features, has emerged as one of the most promising technologies in the field of advanced composite manufacturing. Path planning is a crucial step for determining the fabrication quality of C-FRTP components. This study proposed a new 3D printing path planning strategy driven by the geometric features and tensile properties of C-FRTP components. The strategy employed the properties of the Euler graph to generate the continuous full-field filling paths, ensuring the geometric features of the target components. The intersections were scattered along the printing path to enhance the tensile strength. The feasibility and advantages of the new path planning strategy were validated by comparative experiments with different printing paths. The results indicated that the new strategy not only achieved the geometric features of the target components but significantly enhanced their tensile strength. Using the printing path generated by the new path planning strategy, the tensile strength of specimens featuring mounting holes reached 349.4 MPa, which was only about 4.1 % lower than the tensile strength of continuous fibers at straight paths. Compared to the existing contour-parallel path, the new strategy in this work improved the tensile properties by about 40.9 %. The new path planning strategy proposed in this study shows great potential to design and fabricate C-FRTP components with enhanced mechanical properties for practical applications.

The Recent Research Progress of the Tumor mRNA Vaccine.

Tumors have long posed a significant threat to human life and health, and the messenger ribonucleic acid (mRNA) vaccine is seen as an attractive approach for cancer immunotherapy due to its developmental simplicity, rapid manufacture, and increased immune safety and efficiency. In this review, we have summarized details of the developmental history of mRNA vaccines, discussed the basic molecular structure and the effect on the stable and translation level of mRNA, analyzed the underlying immune efficiency and mechanisms on tumors, and assessed the current status of clinical research. We explored the treatment and application prospects of mRNA vaccines, aiming to provide perspectives on the future of mRNA tumor vaccines for ongoing clinical research.

Valved Microwell Array Platforms for Stepwise Liquid Dispensing.

The fabrication of microarray chips and the precise dispensing of nanoliter to microliter liquids are fundamental for high-throughput parallel biochemical testing. Conventional microwells, typically featuring a uniform cross section, fill completely in a single operation, complicating the introduction of multiple reagents for stepwise and combinatorial analyses. To overcome this limitation, we developed an innovative valved microwell array. Using ultraviolet (UV)-curing resin three-dimensional (3D) printing, these multilayer configurations can be rapidly fabricated through direct template printing and polydimethylsiloxane (PDMS) casting. Each microwell incorporates a microvalve structure, truncating fluids within the upper metering well and allowing transfer to the bottom reservoir well under centrifugal force. Sequential operations enable the introduction of multiple reagents, facilitating orthogonal combinations for complex assays. We explored four types of valving methods: DeepWell, Expansion, Bottleneck, and Membrane valve, each offering varying degrees of design complexity, operational efficiency, robustness, and precision. These methods constitute a versatile toolkit to accommodate a broad spectrum of analytical requirements. Our innovative approach redefines microwell architecture, direct manufacturing techniques, and stepwise fluid dispensation in microarrays.

A novel rapid fabrication method and in-situ densification mechanism for ceramic matrix composite

The extensive application of ceramic matrix composites has always been limited due to the long-period and expensive process. Hence, this research introduces a rapid manufacturing method named as ViSfP-TiCOP (High Viscosity Solvent-free Precursor Combined Elemental Titanium Controlled Pyrolysis). The solvent-free precursor possesses high viscosity (30 °C, 106 mPa S) and wide molecular weight distribution (Mz/Mw = 3.3), accomplishing stable loading of inorganic fillers. Simultaneously, the elementary titanium and ZrB2, as the active and inert filler, are dopped into the precursor to control the pyrolysis. The ViSfP-TiCOP technique offers a rapid method to manufacture CMCs under pressureless and low pyrolysis temperature conditions (1200 °C). Comparing to the addition of ZrB2, the precursor with titanium provides an exceptional ceramic yield of 87 wt%, leading a notable enhancement in the rate of densification. This high densification efficiency is attributed to an in-situ titanium gas-phase reaction, besides with the high degree of cross-linking and low volatile of precursor. After undergoing three cycles of impregnation-pyrolysis, the porosity of C/SiBCN–Ti was discovered to be below 10 vol%, whereas that of C/SiBCN-25 wt%ZrB2 still remained as high as 20.91 vol%. The ViSfP-TiCOP technology can provide guidance for low-cost and rapid preparation of CMCs.

A Study on the Coarse-to-Fine Error Decomposition and Compensation Method of Free-Form Surface Machining

To improve the machining accuracy of free-form surface parts, a coarse-to-fine free-form surface machining error decomposition and compensation method is proposed in this paper. First, the machining error was coarsely decomposed using variational mode decomposition (VMD), and the correlation coefficients between the intrinsic mode function (IMF) and the machining error were obtained to filter out the IMF components that were larger than the thresholding value of the correlation coefficients, which was the coarse systematic error. Second, the coarse systematic errors were finely decomposed using empirical mode decomposition (EMD), which still filters out the IMF components that are larger than the thresholding value of the set correlation coefficient based on the correlation coefficient. Then, the wavelet thresholding method was utilized to finely decompose all the IMF components whose correlation coefficients in the first two decomposition processes were smaller than the threshold value of the correlation coefficient set. The decomposed residual systematic errors were reconstructed with the IMF components screened in the EMD fine decomposition, which gave the fine systematic error. Finally, the machining surface was reconstructed according to the fine systematic error, and its corresponding toolpath was generated to compensate for the machining error without moving the part. The simulation and analysis results of the design show that the method has a more ideal processing error decomposition ability and can decompose the systematic error contained in the processing error in a more complete way. The results of actual machining experiments show that, after using the method proposed in this paper to compensate for the machining error, the maximum absolute machining error decreased from 0.0580 mm to 0.0159 mm, which was a 72.5% reduction, and the average absolute machining error decreased from 0.0472 mm to 0.0059 mm, which was an 87.5% reduction. It was shown that the method was effective and feasible for free-form surface part machining error compensation.

Effect of soy flour and flour improvers on nutritional value, texture, colour and sensory characteristics of wafer biscuits

Biscuits are a popular and desirable snack food by consumers. Still, the quality of these products decreases during the storage process, so this study focuses on improving the wafer's quality and nutritional value and reducing their fragility by partially replacing wheat flour with soybean flour in the following proportions: 5% (T1), 10% (T2), 15% (T3), 20% (T4), and adding ammonium carbonate in different quantities. The sensory evaluation showed that the best wafer treatment was supported with 15% soy flour and 150 g of ammonium carbonate. At the same time, the mean for sensory evaluation is 8.80. Also, the results of the chemical analysis (protein, moisture, fat, carbohydrate, ash, fibre) texture and colour after direct manufacturing and after three months of storage. The result showed a significant increase in the percentage of protein and fat from 6.56±0.30 to 12.19 ± 0.35, 11.56±0.10 to 19.64±0.55, respectively the moisture content was higher in the control was 3.88±0.02 for wafer sample 2.47±0.13, while fibre was 1.93±0.15. The carbohydrates in the control sample were higher than in other treatments. Texture and colour were improved compared with the control. Commercial-batter biscuits with high nutritional value content and high-quality properties can be prepared by replacing wheat flour with 15% soy flour and adding 150 g of ammonium carbonate.

PMMA light channels facilitate the additive manufacturing of complex-structured SiC reflector mirrors

The rapid manufacturing of lightweight SiC reflector mirrors has always posed a formidable challenge. We have successfully solved the problem of SiC slurry’s difficulty in vat photopolymerization by using highly transparent organic particles to construct the light channels for the first time. Through the integration of digital light processing with reaction sintering, we manufactured complex-structured SiC/Si reflector mirrors. Utilizing the light channels constructed with PMMA, ultraviolet light can effectively penetrate SiC slurry, thereby significantly enhancing the curing depth. During subsequent reaction sintering, PMMA particles induce the formation of numerous spherical silicon through dissolution-precipitation mechanism, alleviating stress concentration in the matrix and enhancing the flexural strength of SiC/Si ceramics. The method achieves significantly higher curing depth for SiC slurry and greater flexural strength for ceramic compared to similar materials. Extending the success above further, we have demonstrated their potential as high-quality products for practical applications.

A Novel Approach to Ultrasonic Assisted Coating: Improving Biomechanical Strength of Implants Fabricated through Desktop Manufacturing

A Novel Approach to Ultrasonic Assisted Coating: Improving Biomechanical Strength of Implants Fabricated through Desktop Manufacturing

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.

The effect of heterogeneous geometry on steady-state heat transfer in extrusion-based 3D printed structures

The 3D printed buildings constructed using rapid manufacturing techniques provide opportunities for structural optimization and performance design, which are beneficial in meeting the vision of digital and sustainable development of the construction industry. However, there are still many research gaps in the heat transfer of 3D printed buildings, impacting the accurate design of their thermal performance. This study quantifies the effect of heterogeneous geometry on heat transfer in extrusion-based 3D printed structures. The experiment reveals that the non-uniform surface temperature distribution primarily originates from geometrical factors, with heterogeneous physical properties caused by cold joints having little influence. Numerical simulations using equivalent geometric models indicate that the local temperature and the convective heat transfer coefficient of raised surfaces vary periodically, corresponding to surface shape. As surface bulges increase, the overall average heat transfer efficiency of the 3D printed structure decreases, while total surface heat transfer increases. These findings help to understand the effect of heterogeneous geometric properties on the heat transfer process of 3D printed structures, thus providing a reference for the accurate design of 3D printed structures with thermal functions.

Application of metal additive testing and thermal conductivity technology in optimizing product appearance design in intelligent manufacturing industry

Metal additive manufacturing technology has the advantages of rapid manufacturing and personalized production, but due to the complexity of the manufacturing process and differences in material characteristics, products made with metal additives often have appearance defects and process performance issues. Therefore, the purpose of this study is to explore the application of metal additive detection technology in product appearance design and process performance optimization. This study proposes a comprehensive detection and optimization method that utilizes non-destructive testing techniques to comprehensively inspect metal components. By identifying and locating these issues, the quality status of the components can be accurately understood. Based on the test results, a series of appropriate optimization measures have been taken to improve the appearance and process performance of the product, adjust process parameters, improve the forming quality and surface smoothness of the components, thereby achieving better appearance effects. Metal additive testing technology can effectively detect and locate appearance defects in products, and by optimizing process parameters and material selection, it can significantly improve the appearance quality and process performance of products, providing support for improving the reliability and production efficiency of industrial manufacturing.

Evaluating the impacts of surface roughness and microstructure on the size effect in two additively manufactured stainless steels

Laser powder bed fusion (L-PBF) enables direct manufacturing of components with complex geometries and thin walls, but many authors report size-dependent mechanical properties that may complicate design. Size effects are commonly attributed to surface roughness, microstructure, and/or internal defects, but the relative importance of each is still not fully understood. To systematically study these effects, L-PBF specimens made of two microstructurally-distinct stainless steels (17-4PH and 316L) were manufactured and mechanically tested, in varied heat-treatment conditions and across a range of thicknesses and build angles. It was found that the size-dependent mechanical properties are efficiently predicted by the ratio of surface roughness to specimen thickness, Ra/t, in a way that is relatively microstructure-agnostic. This metric is particularly useful for predicting ultimate strength and elongation, while microstructure moderates its predictive power for yield strength, especially in the more processing-sensitive 17-4PH. When considered in isolation, thickness or surface roughness had weaker correlations with mechanical properties and, importantly, tended to correlate much more strongly with one steel's properties than the other's. Comparing this comprehensive dataset with summary data from other researchers highlights the utility of Ra/t, and provides semi-quantitative estimates of the relative impacts of porosity, microstructure, and Ra/t on size-dependent properties.