Manufacturing Considerations Research Articles

Additively manufactured ultra-high vacuum chamber for portable quantum technologies

Additive manufacturing is having a dramatic impact on research and industry across multiple sectors, but the production of additively manufactured systems for ultra-high vacuum applications has so far proved elusive and widely been considered impossible. We demonstrate the first additively manufactured vacuum chamber operating at a pressure below 10−10 mbar, measured via an ion pump current reading, and show that the corresponding upper limit on the total gas output of the additively manufactured material is 3.6 × 10−13 mbar l/(s mm2). The chamber is produced from AlSi10Mg by laser powder bed fusion. Detailed surface analysis reveals that an oxidised, Mg-rich surface layer forms on the additively manufactured material and plays a key role in enabling vacuum compatibility. Our results not only enable lightweight, compact versions of existing systems, but also facilitate rapid prototyping and unlock hitherto inaccessible options in experimental science by removing the constraints that traditional manufacturing considerations impose on component design. This is particularly relevant to the burgeoning field of portable quantum sensors — a point that we illustrate by using the chamber to create a magneto-optical trap for cold 85Rb atoms — and will impact significantly on all application areas of high and ultra-high vacuum.

Considerations Using Additive Manufacture of Emulsion Inks to Produce Respiratory Protective Filters Against Viral Respiratory Tract Infections Such as the COVID-19 Virus

This review paper explores the potential of combining emulsion-based inks with additive manufacturing (AM) to produce filters for respiratory protective equipment (RPE) in the fight against viral and bacterial infections of the respiratory tract. The value of these filters has been highlighted by the current severe acute respiratory syndrome coronavirus-2 crisis where the importance of protective equipment for health care workers cannot be overstated. Three-dimensional (3D) printing of emulsions is an emerging technology built on a well-established field of emulsion templating to produce porous materials such as polymerized high internal phase emulsions (polyHIPEs). PolyHIPE-based porous polymers have tailorable porosity from the submicron to 100 s of µm. Advances in 3D printing technology enables the control of the bulk shape while a micron porosity is controlled independently by the emulsion-based ink. Herein, we present an overview of the current polyHIPE-based filter applications. Then, we discuss the current use of emulsion templating combined with stereolithography and extrusion-based AM technologies. The benefits and limitation of various AM techniques are discussed, as well as considerations for a scalable manufacture of a polyHIPE-based RPE.

Fiber-Based Gas Filter Assembled via In Situ Synthesis of ZIF-8 Metal Organic Frameworks for an Optimal Adsorption of SO2: Experimental and Theoretical Approaches.

For environmental protection from exposure to airborne toxic gases, metal organic frameworks (MOFs) have drawn great attention as gas adsorbent options, with their advantages in chemical tailorability and large porosity. To develop a fiber-based gas filter that is effective against SO2 gas, zeolite imidazole framework-8 (ZIF-8) was applied to polypropylene nonwoven by various methods. Among the tested methods, the sol-gel impregnation method showed the highest ZIF-8 loading efficiency. There existed an optimal loading of ZIF-8 for the maximum adsorption efficiency, and it was associated with the accessibility of gas molecules to the ZIF-8 pores and active sites. Dominant adsorption processes and mechanisms were investigated by fitting the theoretical sorption models to experimental data. The results demonstrate that the increased ZIF-8 loading to fibers, beyond a certain level, may hinder the diffusivity and increase the barrier effect, eventually decreasing the adsorption efficiency. This study is novel and significant in that a multifaceted approach, including experimental analysis, theoretical investigation, and computational modeling, was made for scrutinizing the intricate phenomena occurring in the gas sorption process. The results of this study provide the fundamental yet practical information on the manufacturing considerations for the optimal design of MOF-loaded fibrous adsorbents.

Post-printing characterisation and design for additive manufacturing considerations for conductive tracks 3D-printed by material extrusion

Post-printing characterisation and design for additive manufacturing considerations for conductive tracks 3D-printed by material extrusion

Post-printing Characterisation and Design for Additive Manufacturing Considerations for Conductive Tracks 3D Printed by Material Extrusion

Post-printing Characterisation and Design for Additive Manufacturing Considerations for Conductive Tracks 3D Printed by Material Extrusion

Design considerations for multi-terawatt scale manufacturing of existing and future photovoltaic technologies: challenges and opportunities related to silver, indium and bismuth consumption

As the photovoltaic (PV) industry heading towards the multi-TW scale, PV technologies need to be carefully evaluated based on material consumption rather than just efficiency or cost to ensure sustainable growth of the industry.

Solving Facility Layout Problem with safety consideration of Reconfigurable Manufacturing and Assembly Systems

Reconfigurable Manufacturing Systems (RMS) are designed to cope with mass customization problem. Reconfigurable Assembly Systems (RAS) are a variant of this RMS concept in the assembly field. One of the most crucial issues in designing the RAS is the layout problem with human safety considerations. This paper’s main motivation is to propose a methodology to determine the most efficient and safe arrangement of facilities in a workshop. The objective is twofold: (i) to minimize the Material Handling Cost and (ii) to ensure human safety by applying "safety bubble". An implementation of the approach and an illustrative case study are presented.

Consideration of SLM additive manufacturing supports on the stability of flexible structures in finish milling

The supports in additive manufacturing can be used in an innovative way by being considered as supports for machining operation. This innovative use of manufacturing supports can facilitate the finishing of functional thin structures. But the flexible global workpiece-supports system can potentially cause vibrations during the machining operation. This can cause irregular surfaces with bad quality. This study highlights the importance of additively manufactured support structures on the stability of Ti-6Al-4 V parts milling by using supports as a machining fixture. Nowadays, the control of the support stiffness and mechanical properties is not proposed by specific AM software. A way to develop a numerical method to optimize the post-processing of additive manufacturing parts is to use specific lattice structures as supports. Indeed, by adjusting the topology and the beam diameter of lattices, the relative stiffness and the relative density of the global structure can be controlled. The objective of this study is to show that the stiffness of the manufacturing supports is crucial for the machining operation. To validate this concept, milling tests are proceeded on thin-walled plates produced by Selective Laser Melting (SLM) using defined finish milling cutting conditions. Three types of results are obtained: cutting forces signals, displacements and surface qualities by confocal microscopy. The study reveals that milling can induces chatters. Also, surface qualities and dimensional deviations depend on the support choice. The control of mechanical properties of support structures appears to be a good way to favor machining operation of flexible and thin-walled structures. Topology and dimensional parameters of supports have to be considered in preliminary design steps of the additive manufacturing digital chain.

Core crosstalk in ordered imaging fiber bundles.

Coherent fiber bundles are used widely for imaging. Commonly, disordered arrays of randomly sized fiber cores avoid proximity between like-cores, which would otherwise result in increased core crosstalk and a negative impact on imaging. Recently, stack-and-draw fiber manufacture techniques have been used to produce fibers with a controlled core layout to minimize core crosstalk. However, one must take manufacturing considerations into account during stack-and-draw fiber design in order to avoid impractical or unachievable fabrication. This comes with a set of practical compromises, such as using only a small number of different core sizes. Through characterization of core crosstalk patterns, this Letter aims to aid the understanding of crosstalk limitations imposed by such compromises in the core layout made for ease of fabrication.

A Review of Problem Structuring Methods for Consideration in Prognostics and Smart Manufacturing

Successful use of prognostics involves the prediction of future system behaviors in an effort to maintain system availability and reduce the cost of maintenance and repairs. Recent work by the National Institute of Standards and Technology indicates that the field of prognostics and health management is vital for remaining competitive in today’s manufacturing environment. While prognostics-based maintenance involves many traditional operations researchcentric challenges for successful deployment such as limited availability of information and concerns regarding computational efficiency, the authors argue in this paper that the field of prognostics and health management, still in its embryonic development stage, could benefit greatly from considering soft operations research techniques as well. Specifically, the authors propose the use of qualitative problem structuring techniques that aid in problem understanding and scoping. This paper provides an overview of these soft methods and discusses and demonstrates how manufacturers might use them. An approach combining problem structuring methods with traditional operations research techniques would help accelerate the development of the prognostics field.

Antimicrobial nanoparticle coatings for medical implants: Design challenges and prospects.

Microbial colonization, infection, and biofilm formation are major complications in the use of implants and are the predominant risk factors in implant failure. Although aseptic surgery and the administration of antimicrobial drugs may reduce the risk of infection, the systemic use of antibiotics can lead to a lack of efficacy, an increase in the risk of tissue toxicity, and the development of drug-resistant infections. To reduce implant-related infections, antimicrobial materials are increasingly being investigated and applied to implant surfaces using various methods depending on the agents and their microbicidal mechanisms. Through the development of biomaterials and nanotechnology, antimicrobial nanoparticles are becoming promising candidates for implant coatings, as their multifactorial antimicrobial mechanisms combat microbial adherence, viability, and biofilm formation. Despite their antimicrobial promise, the application of nanoparticles onto implant surfaces while retaining their antimicrobial potency faces many challenges. Herein, we review the potential and challenges associated with the design and implementation of antimicrobial nanoparticle coatings for the medical implant industry, particularly focusing on manufacturing considerations, sterilization, long-term stability, protein fouling, regulation, and safety, with a view to providing researchers the necessary tools to aid the translation of materials from the bench to the clinic.

Critical Considerations for Regeneration of Vascularized Composite Tissues.

Effective vascularization is vital for survival and functionality of complex tissue-engineered organs. The formation of the microvasculature, composed of endothelial cells (ECs) alone, has been mostly used to restore the vascular networks in organs. However, recent heterocellular studies demonstrate that co-culturing is a more effective approach in revascularization of engineered organs. This review presents key considerations for manufacturing of artificial vascularized composite tissues. We summarize the importance of co-cultures and the multicellular interactions with ECs, as well as design and use of bioreactors, as critical considerations for tissue vascularization. In addition, as an emerging scaffolding technique, this review also highlights the current caveats and hurdles associated with three-dimensional bioprinting and discusses recent developments in bioprinting strategies such as four-dimensional bioprinting and its future outlook for manufacturing of vascularized tissue constructs. Finally, the review concludes with addressing the critical challenges in the regulatory pathway and clinical translation of artificial composite tissue grafts. Impact statement Regeneration of composite tissues is critical as biophysical and biochemical characteristics differ between various types of tissues. Engineering a vascularized composite tissue has remained unresolved and requires additional evaluations along with optimization of methodologies and standard operating procedures. To this end, the main hurdle is creating a viable vascular endothelium that remains functional for a longer duration postimplantation, and can be manufactured using clinically appropriate source of cell lines that are scalable in vitro for the fabrication of human-scale organs. This review presents key considerations for regeneration and manufacturing of vascularized composite tissues as the field advances.

An integrative approach for evaluating the environmental economic efficiency

This literature presents an integrative approach using an extended Kaya identity-based LMDI decomposition analysis (Logarithmic Mean Divisia Index) with a two-stage data envelope analysis (DEA) to identify causes for changes in energy consumption and CO2 emissions and to evaluate environmental and economic efficiency. An LMDI can express the corresponding contributions between inputs and outputs by converting all variables into rates of change. These ratios can help avoid the zero and negative values in DEA. The energy consumption, CO2 emissions and economic components of the countries covered by the Belt and Road Initiative from 1992 to 2017 are used for the two-stage efficiency assessment. The outcomes lead to some policy suggestions for the BRI countries. We find that the labor market, labor productivity and energy intensity are the main drivers of energy consumption. Demographic change and carbon intensity are the main influencers of CO2 emissions. The economic situation and the field of activity have an impact on energy consumption and CO2 emissions. Higher-income countries do better in both energy and economic efficiencies, but should be given more consideration in manufacturing. Finally, this integrative approach has a better goodness of fit than the isolated DEA.

Strategies for high-concentration drug substance manufacturing to facilitate subcutaneous administration: A review.

To achieve the high protein concentrations required for subcutaneous administration of biologic therapeutics, numerous manufacturing process challenges are often encountered. From an operational perspective, high protein concentrations result in highly viscous solutions, which can cause pressure increases during ultrafiltration. This can also lead to low flux during ultrafiltration and sterile filtration, resulting in long processing times. In addition, there is a greater risk of product loss from the hold-up volumes during filtration operations. From a formulation perspective, higher protein concentrations present the risk of higher aggregation rates as the closer proximity of the constituent species results in stronger attractive intermolecular interactions and higher frequency of self-association events. There are also challenges in achieving pH and excipient concentration targets in the ultrafiltration/diafiltration (UF/DF) step due to volume exclusion and Donnan equilibrium effects, which are exacerbated at higher protein concentrations. This paper highlights strategies to address these challenges, including the use of viscosity-lowering excipients, appropriate selection of UF/DF cassettes with modified membranes and/or improved flow channel design, and increased understanding of pH and excipient behavior during UF/DF. Additional considerations for high-concentration drug substance manufacturing, such as appearance attributes, stability, and freezing and handling are also discussed. These strategies can be employed to overcome the manufacturing process challenges and streamline process development efforts for high-concentration drug substance manufacturing.

Geometric considerations for the 3D printing of components using fused filament fabrication

Demand in 3D printing products using fused filament fabrication (FFF) in industry has been growth a lot with 55% in development of prototypes, 43% in production, and 41% in conceptual models for testing. However, information regarding the manufacturing considerations of geometry-restricted components is still an opportunity area, generating printed components with quality defects. This article is aimed to present some characteristics in geometric components that should be considered during the developing process for components to be produced in FFF to avoid in quality defects. The methodology used considers three stages: first, the reproduction of basic geometric elements and a template that integrates elements with software design; second, the component analysis and the template with software for pre-processing of components, and third, the printing of a template for assumption validation identified in stage two. Findings obtained indicate that the spherical components are geometries with the greatest possibility of defect generation during the FFF printing process. The complexity of the template allowed to identify that the template orientation is a factor that generates defects; for example, with 0° orientation regarding the X axis generates 40,008 risk points for defect and for 30° orientation there are 6658 risk point defects. Therefore, it is advisable to consider avoid geometries associated with sphericity and cylindrical characteristics as possible in the design processes, since these geometries require specific processes to achieve the finishing quality.

CHALLENGES FACED BY DESIGN ENGINEERS WHEN CONSIDERING MANUFACTURING IN DESIGN – AN INTERVIEW STUDY

AbstractThe consideration of manufacturing in design is still a challenge for design engineers. This paper presents the results of an interview study, conducted with 15 participants. 4 challenges are identified in this study: Manufacturing-specific knowledge is mostly not sufficient. The design of manufacturing-oriented concepts in terms of costs is difficult. The feasibility of manufacturing is not assessed. The dimension of cost drivers is unknown, hindering optimisation in early stages of design. Based on these results the need for further research emerges regarding the impact of these challenges.

Important considerations for cell therapy manufacturing of mesenchymal stem cell

Background & Aim Recent advances in cell therapy manufacturing, e.g. microcarrier-based 3D culture and perfusion, have paved the way for cost-effective large-scale expansion of mesenchymal stem cells (MSCs). In particular, perfusion and enhanced feed boosts allow the culture to reach increasingly high cell densities. Although the high cell density is favorable to customers due to the low cost and high cell dose requirements, we should not overlook its impact on cell quality. Here, we studied the correlation between 3D culture cell density with a variety of commonly used cell quality parameters for both fresh and post-thaw cells. Methods, Results & Conclusion MSC 3D cultures were carried out using different microcarriers (Cultispher-G, dissolvable Corning Synthemax, and Pall SoloHill collagen) and media in spinner flasks and stirred-tank bioreactors. MSCs were able to expand on all microcarriers (Figure1), reaching a final density of 0.6 to 1 million cells/mL. Attachment and proliferation capacities of 3D-expanded MSCs, harvested at different cell densities, were assessed by culturing them post-harvest on 2D flatware. Figure2 shows that MSCs harvested at low cell densities (day4) proliferated significantly higher than MSCs harvested at high cell densities (day5-8). Similar pattern was observed for 3D-cultured MSCs post-thaw. Cell viability was also evaluated for both fresh and post-thaw MSCs harvested at low and high cell densities. For most cases, MSCs harvested at both low and high cell densities, showed above 90% viability over 0-6 hours (Figure3). MSCs expanded using SoloHill microcarriers displayed >90% post-thaw viability for both low and high cell densities. However, dissolvable Corning-Synthemax exhibited up to 12% and 30% drops, and Cultispher-G up to 24% and 51% drops for low and high cell density groups, respectively. Figure3 also shows that the extent of decline in post-thaw vibility was higher for MSCs harvested at high cell densities versus low cell densities. In conclusions, our findings indicated that the extended 3D culture (i.e. harvesting at higher cell densities) led to compromising attachment and proliferation capacities of MSCs, regardless of the choice of microcarrier. For Cultispher-G and dissolvable Coning-Synthemax, we observed 20-30% lower cell viabilities for MSCs harvested at high densities compared to low densities.

Funding the Development and Manufacturing of COVID-19 Vaccines

The SARS-CoV-2 virus, which causes COVID-19, has quickly spread worldwide. On January 30, 2020, the WHO declared COVID-19 to be a Public Health Emergency of International Concern and advised all governments to prepare for transmission in their countries. On March 11, 2020, the WHO declared that it had become a pandemic. There is uncertainty about what will happen next, e.g., the pandemic could involve multiple simultaneous epidemics of COVID-19 over 1-3 years, and/or SARS-CoV-2 could become a globally endemic virus. In this paper, we begin by arguing that the rapid development and scale-up of COVID-19 vaccines has become critical to reducing the morbidity, mortality, and economic damage associated with a pandemic. We show that new funding for COVID-19 vaccine development is required for all development stages and we estimate how much funding is needed. We examine ways to mobilize such funding and explore potential funding vehicles, including CEPI, the Coalition for Epidemic Preparedness Innovations, as well as the governance of such vehicles. Finally, we highlight issues such as vaccine manufacturing, intellectual property, global access, regulatory approval, and ethical and trial design considerations in conducting trials in the midst of the COVID-19 outbreak.

Umbilical cord-derived CD362+ mesenchymal stromal cells for E. coli pneumonia: impact of dose regimen, passage, cryopreservation, and antibiotic therapy

BackgroundMesenchymal stromal cells (MSCs) demonstrate considerable promise for acute respiratory distress syndrome (ARDS) and sepsis. However, standard approaches to MSC isolation generate highly heterogeneous cell populations, while bone marrow (BM) constitutes a limited and difficult to access MSC source. Furthermore, a range of cell manufacturing considerations and clinical setting practicalities remain to be explored.MethodsAdult male rats were subject to E. coli-induced pneumonia and administered CD362+ umbilical cord (UC)-hMSCs using a variety of cell production and clinical relevance considerations. In series 1, animals were instilled with E. coli and randomized to receive heterogeneous BM or UC-hMSCs or CD362+ UC-hMSCs. Subsequent series examined the impact of concomitant antibiotic therapy, MSC therapeutic cryopreservation (cryopreserved vs fresh CD362+ UC-hMSCs), impact of cell passage on efficacy (passages 3 vs 5 vs 7 vs 10), and delay of administration of cell therapy (0 h vs 6 h post-injury vs 6 h + 12 h) following E. coli installation.ResultsCD362+ UC-hMSCs were as effective as heterogonous MSCs in reducing E. coli-induced acute lung injury, improving oxygenation, decreasing bacterial load, reducing histologic injury, and ameliorating inflammatory marker levels. Cryopreserved CD362+ UC-hMSCs recapitulated this efficacy, attenuating E. coli-induced injury, but therapeutic relevance did not extend beyond passage 3 for all indices. CD362+ UC-hMSCs maintained efficacy in the presence of antibiotic therapy and rescued the animal from E. coli injury when delivered at 6 h + 12 h, following E. coli instillation.ConclusionsThese translational studies demonstrated the efficacy of CD362+ UC-hMSCs, where they decreased the severity of E. coli-induced pneumonia, maintained efficacy following cryopreservation, were more effective at early passage, were effective in the presence of antibiotic therapy, and could continue to provide benefit at later time points following E. coli injury.

But Will It Build? Assessing Student Engineering Designers’ Use of Design for Additive Manufacturing Considerations in Design Outcomes

Abstract Additive manufacturing (AM) enables engineers to improve the functionality and performance of their designs by adding complexity at little to no additional cost. However, AM processes also exhibit certain unique limitations, such as the presence of support material. These limitations must be accounted for to ensure that designs can be manufactured feasibly and cost-effectively. Given these unique process characteristics, it is important for an AM-trained workforce to be able to incorporate both opportunistic and restrictive design for AM (DfAM) considerations into the design process. While AM/DfAM educational interventions have been discussed in the literature, few studies have objectively assessed the integration of DfAM in student engineering designers’ design outcomes. Furthermore, limited research has explored how the use of DfAM affects the students’ AM designs’ achievement of design task objectives. This research explores this gap in literature through an experimental study with 301 undergraduate students. Specifically, participants were exposed to either restrictive DfAM or dual DfAM (both opportunistic and restrictive) and then asked to participate in a design challenge. The participants’ final designs were evaluated for (1) build time and build material (2) the use of the various DfAM concepts, and (3) the features used to manifest these DfAM concepts. The results show that the use of certain DfAM considerations, such as part complexity, number of parts, support material mass, and build plate contact area (corresponding to warping tendency), correlated with the build material and build time of the AM designs—minimizing both of which were objectives of the design task. The results also show that introducing participants to opportunistic DfAM leads to the generation of designs with higher part complexity and lower build plate contact area but a greater presence of inaccessible support material.