3D Printing Research Articles

The role of robots in the construction industry

Purpose The purpose of this study is to provide details of the robots used in construction and an insight into how the technology can contribute to addressing the challenges facing the industry. Design/methodology/approach Following an introduction which identifies key challenges facing the construction industry, this study discusses robotic 3D structural printing, the role of drones, ground vehicles, bricklaying, welding and other robotic application. Finally, brief conclusions are drawn. Findings The construction industry faces significant challenges: labour shortages, a poor safety record, near static productivity, slow adoption of new technology and an adverse environmental impact. A diverse range of robots are finding uses in this industry and can automate or enhance many traditional practices. These yield benefits which include reduced manpower requirements, improved safety, better productivity, lower environmental impact and increased overall efficiency, thereby addressing many of the challenges facing the industry. Originality/value This study provides details of robots used in construction industry and how they can address the challenges confronting the industry.

Inclusive Museum Engagement: Multisensory Storytelling of Cagli Warriors’ Journey and the Via Flamina Landscape Through Interactive Tactile Experiences and Digital Replicas

This paper presents a case study from the Archaeological and Via Flaminia Museum in Cagli (Italy), developed within the ERASMUS+ Next-Museum project, which explores inclusive approaches through the digital transformation of small museums and their connection to the surrounding territory. A key goal was to “return” bronze statuettes to the museum, symbolically compensating the community for their absence. The initiative integrates accessibility and multisensory storytelling following “Design for All” principles. Three installations were implemented: tactile replicas of the statuettes produced through 3D printing, a sensorized table for interactive storytelling, and a story map displayed on a touchscreen for exploring local archaeological heritage. The design prioritized inclusivity, particularly for visitors with visual impairments, while addressing practical constraints such as the need for a mobile and flexible setup within a limited budget. Verification and validation tests were conducted with visually impaired participants during the pre-opening phase, and the installations were later evaluated using the User Experience Questionnaire, complemented by qualitative feedback. These evaluations highlight the potential of phygital experiences to foster engagement with cultural heritage while addressing technological and design challenges.

Heteroleptic Copper(I) Complexes with Pyridine-Benzothiazole Ligands as Photocatalysts for Free Radical Photopolymerization and 3D Printing

Heteroleptic Copper(I) Complexes with Pyridine-Benzothiazole Ligands as Photocatalysts for Free Radical Photopolymerization and 3D Printing

Systematic Review of the Quality of Stereolithographic Three-Dimensionally Printed Materials for Provisional Dental Restorations

Background and Objectives: The use of stereolithographic (SLA) 3D printing technology in dentistry has expanded, particularly for the fabrication of provisional dental restorations. Understanding the mechanical properties and quality of SLA 3D-printed materials is essential to ensure clinical success and patient safety. This systematic review aims to critically evaluate and summarize the available evidence on the mechanical properties and quality of SLA 3D-printed materials. Methods: A comprehensive literature search was conducted in PubMed, Scopus, Embase, Cochrane, and Web of Science up to October 2024. Studies comparing the mechanical properties of SLA 3D-printed provisional restoration materials with those of milled, conventional, or other additive manufacturing methods were included. Nine studies met the inclusion criteria. Data on flexural strength, hardness, fracture resistance, surface roughness, marginal adaptation, accuracy, cement film thickness, shear bond strength, and biofilm formation were extracted and analyzed. Results: The findings from the included studies indicate that SLA 3D-printed materials exhibit varied mechanical properties. Some studies reported that SLA 3D-printed resins had significantly lower flexural strength and hardness compared to milled PMMA and bis-acrylic resins. Other studies found that SLA 3D-printed resins showed clinically acceptable marginal adaptation, surface roughness, and fracture strength comparable to those fabricated by subtractive manufacturing and conventional methods. In terms of accuracy, build orientation influenced the dimensional accuracy of SLA-printed restorations. Studies assessing cement film thickness found that SLA-printed provisional restorations had higher cement film thickness compared to other materials. Regarding repairability and fatigue resistance, limitations were observed in some SLA resins. Conclusions: The mechanical properties and quality of SLA 3D-printed materials for provisional dental restorations vary among studies. While SLA technology holds promise for efficient fabrication of provisional restorations, inconsistencies in material properties suggest a need for further research to optimize materials and printing parameters. Standardization of protocols is necessary to ensure reliable clinical performance of SLA 3D-printed provisional restorations.

Spiked Systems for Colonic Drug Delivery: Architectural Opportunities and Quality Assurance of Selective Laser Sintering.

Additive manufacturing has been a breakthrough therapy for the pharmaceutical industry raising opportunities for long-quested properties, such as controlled drug-delivery. The aim of this study was to explore the geometrical capabilities of selective laser sintering (SLS) by creating spiked (tapered-edged) drug-loaded specimens for administration in colon. Poly(vinyl alcohol) (PVA) was used as the binding material and loperamide hydrochloride was incorporated as the active ingredient. Printing was feasible without the addition of a sintering agent or other additives. Innovative printing protocols were developed to help improve the quality of the obtained products. Intentional vibrations were applied on the powder bed through rapid movements of the printing platform in order to facilitate rigidity and consistency of the printed objects. The drug-loaded products had physicochemical properties that met the pharmacopoeia standards and exhibited good biocompatibility. The behavior of spiked balls (spherical objects with prominent spikes) and their retention time in the colon was assessed using a custom ex vivo intestinal setup. The spiked balls showed favorable mucoadhesive properties over the unspiked ones. No movement on the tissue was recorded for the spiked balls, and specimens with more spikes exhibited longer retention times and potentially, enhanced bioavailability. Our results suggest that SLS 3D printing is a versatile technology that holds the potential to revolutionize drug delivery systems by enabling the creation of complex geometries and medications with tunable properties.

Three-Dimensional Printed Cardiac Models Demonstrating Extensive Cardiac Calcification Assist in Preprocedural Planning.

Cardiac calcification is common in adults with congenital heart disease, typically affecting surgical sites and prosthetic material. Understanding the precise location and degree of calcification is important during the decision-making process prior to possible intervention but can be difficult to determine in different imaging modalities. Advances in three-dimensional (3D) modeling and printing have made it possible to distinguish different tissue types and accurately display them in different colors on printed models. We present two adult congenital heart disease patients where advanced 3D printing was used to demonstrate cardiac calcification and aided the preprocedural planning process.

3D printing driving innovations in extreme low-temperature energy storage

3D printing driving innovations in extreme low-temperature energy storage

Digital light processing three-dimensional printing with acrylic–titanium composite powders for multiscale porous scaffolds

Abstract Porous metals fabricated via three-dimensional (3D) printing have attracted extensive attention in many fields owing to their open pores and customization potential. However, dense internal structures produced by the powder bed fusion technique fails to meet the feature of porous materials in scenarios that demand large specific surface areas. Herein, we propose a strategy for 3D printing of titanium scaffolds featuring multiscale porous internal structures via powder modification and digital light processing (DLP). After modification, the titanium powders were composited with acrylic resin and maintained spherical shapes. Compared with the raw powder slurries, the modified powder slurries exhibited higher stability and preferable curing characteristics, and the depth sensitivity of the modified powder slurries with 45 vol% solid loading increased by approximately 72%. Green scaffolds were subsequently printed from the slurries with a solid loading reaching 45 vol% via DLP 3D printing. The scaffolds had macropores (pore diameters of approximately 1 mm) and internal open micropores (pore diameters of approximately 5.7–13.0 μm) after sintering. Additionally, these small-featured (approximately 320 μm) scaffolds retained sufficient compressive strength ((70.01 ± 3.53) MPa) even with high porosity (approximately 73.95%). This work can facilitate the fabrication of multiscale porous metal scaffolds with high solid loading slurries, offering potential for applications requiring high specific surface area ratios.

Design and development of a customized 3D-printed assistive device using modular 3D blocks

Purpose 3D printing enables the production of customizable, cost-effective, and reproducible items, making it a promising approach for manufacturing assistive devices. This study aims to develop customized 3D-printed assistive devices using 3D blocks. Methods A 3D scanner was used to scan the limbs and trunks where the devices would be worn. The study utilized 3D blocks capable of undergoing subdivision surfaces to match the scanned external appearance of limbs and trunks. The mass-spring model and Gauss-Newton method were applied to optimize the subdivision surfaces, ensuring a better fit for users’ hand shapes. Additionally, 3D blocks were used as design units for blending-based morphing, generating diverse 3D patterns. Results The proposed approach successfully enabled real-time manufacturing of customized external appearances for assistive devices. The resulting designs met usability, functionality, and aesthetic requirements. Usability testing, conducted using the Quebec User Evaluation of Satisfaction with Assistive Technology, demonstrated high satisfaction scores, confirming the effectiveness of 3D blocks in customizing assistive devices. Conclusions By integrating 3D scanning and printing technologies, this study highlights the feasibility of using reverse engineering to develop personalized assistive devices. The findings suggest that the proposed method enhances user satisfaction and provides a practical approach to assistive device customization.

Cost–effective additive manufacturing of metal parts using pneumatic extrusion: investigation of the sintering process

Purpose The purpose of this study is to develop a low-cost and efficient method for 3D printing CuSn15 bronze alloy parts using a pneumatic extrusion system. By avoiding complex processes such as filament preparation and solvent/catalytic debinding, the study aims to streamline the low-cost production process of metallic components while maintaining high mechanical performance. The research also seeks to evaluate the effects of different sintering temperatures and times on the mechanical properties of the printed parts. Design/methodology/approach A simple and cost-effective pneumatic extrusion system was designed to 3D print a metal paste containing CuSn15 alloy powders. The metal paste was prepared by manually mixing of CuSn15 powders, carboxymethyl cellulose and distilled water. The printed parts were subsequently dried and sintered at various temperatures and times to study the effects of these parameters on the material properties. Tensile test and scanning electron microscope analysis were conducted to assess the structural integrity and mechanical performance of the samples. Findings The study found that the pneumatic extrusion system enabled the successful 3D printing of CuSn15 bronze alloy parts without the need for complex processes. Increasing sintering temperature led to improved mechanical properties and decreased porosity. Increasing the sintering time at 820 °C led to a reduction in mechanical performance. The study demonstrated that the sintering parameters significantly influence the porosity and mechanical properties of the printed parts. Originality/value This study introduces a novel approach to 3D printing CuSn15 bronze alloy using a pneumatic extrusion system, eliminating the need for traditional filament preparation and solvent/catalytic debinding processes. The research provides new insights into the effect of sintering parameters on the mechanical properties of additively manufactured metal parts. By simplifying the production process, this study offers a low-cost, efficient method for producing complex-shaped metallic components, potentially expanding the applicability of 3D printing in industries such as electronics, marine and mechanical engineering.

3D printed polycaprolactone/poly (L-lactide-co-ε-caprolactone) composite ureteral stent with biodegradable and antibacterial properties.

The clinical application of biodegradable ureteral stents holds significant potential. There is an urgent need to develop new materials for ureteral stents to address the limitations related to performance degradation and antibacterial properties observed in current designs. Here, we developed a Polycaprolactone (PCL)/Poly (L-lactide-co-ε-caprolactone) (PLCL) composite ureteral stent by 3D printing, which exhibits biodegradable and antibacterial properties. Silver nanoparticles (AgNPs) were bonded to the surface of the stent through the polymerization of dopamine (PDA) and coating with type I collagen (Col I). The ureteral stent (PP-PDA-Ag-Col) had a densely spiraled structure and higher hydrophilicity. The release behavior of silver ions from the stent was found to be slow and continuous when coated with AgNPs, which can enable long-term antibacterial effects after being implanted in vivo. Additionally, in vitro degradation experiments demonstrated that the different ratios of ureteral stents degraded slowly in artificial urine over 6 weeks without compromising functionality. The stent exhibits excellent hemocompatibility and cell compatibility. The subcutaneous implantation experiment in SD rats showed that the PP-PDA-Ag-Col stent degraded slowly in vivo and had good biocompatibility. The stent PCL5/PLCL5 was the most promising ureteral stent regarding antibacterial, mechanical properties, and degradation. The novel 3D-printed PP-PDA-Ag-Col stent exhibits biocompatibility for safe in vivo transplantation and antibacterial properties that reduce reliance on antibiotics. Additionally, its biodegradability eliminates the need for secondary surgical removal, making it a promising option for the clinical application of ureteral stents.

Multimaterial Bonding of Additively Manufactured Carbon Fiber‐Reinforced Thermoplastics/64 Titanium

The integration of lightweight materials in hybrid structures is critical for achieving energy efficiency in automotive and aerospace industries. This study presents a novel method for directly bonding carbon‐fiber‐reinforced thermoplastics to Ti6Al4V titanium alloy (64Ti) substrates using fused filament fabrication 3D printing. The technique involves 3D printing short carbon fiber‐reinforced polyamide 6 onto sandblasted 64Ti substrates, heated via a hot plate integrated into the 3D printer. Lap‐shear tests reveal that adhesion strength improves with increased fusion time, achieving a maximum shear stress of 27.3 ± 2.2 MPa for 60 min welding. Finite element analysis demonstrates stress concentrations at the adhesion edges and highlights the formation of a fracture process zone with localized plastic deformation and microcrack generation. Additionally, the feasibility of fabricating 3D structures and integrating continuous carbon fiber‐reinforced thermoplastics onto 64Ti substrates is demonstrated. This study advances hybrid material joining techniques by providing a cost‐effective, scalable method for achieving robust metal‐composite bonds suitable for structural applications.

Accelerated Multiobjective Calibration of Fused Deposition Modeling 3D Printers Using Multitask Bayesian Optimization and Computer Vision

Proper process parameter calibration is critical to the success of fused deposition modeling (FDM) three‐dimensional (3D) printing, but is time‐consuming and requires expertise. While existing systems for autonomous calibration have demonstrated success in calibrating for a single objective, users may need to balance multiple conflicting objectives. Herein, an easily deployable, camera‐based system for autonomous calibration of FDM printers that optimizes for both part quality and completion time is presented. Autonomous calibration is achieved through a novel, multifaceted computer vision characterization and a multitask learning extension to Bayesian optimization. The system is demonstrated on four popular filament types using two distinct 3D printers. The results show that the system significantly outperforms manufacturer calibration across the machine and material configurations, achieving an average improvement of 32.2% in quality and a 31.2% decrease in completion time with respect to a popular benchmark.

Bio-inspired 3D printing approach for bonding soft and rigid materials through underextrusion

Vertebrate animals benefit from a combination of rigidity for structural support and softness for adaptation. Similarly, integrating rigidity and softness can enhance the versatility of soft robotics. However, the challenges associated with creating durable bonding interfaces between soft and rigid materials have limited the development of hybrid robots. Existing solutions require specialized machinery, such as polyjet 3D printers, which are not commonly available. In response to these challenges, we have developed a 3D printing technique that can be used with almost all commercially available FDM printers. This technique leverages the common issue of underextrusion to create a strong bond between soft and rigid materials. Underextrusion generates a porous structure, similar to fibrous connective tissues, that provides a robust interface with the rigid part through layer fusion, while the porosity enables interlocking with the soft material. Our experiments demonstrated that this method outperforms conventional adhesives commonly used in soft robotics, achieving nearly 200% of the bonding strength in both lap shear and peeling tests. Additionally, we investigated how different porosity levels affect bonding strength. We tested the technique under pressure scenarios critical to soft and hybrid robots and achieved three times more pressure than the current adhesion solution. Finally, we fabricated various hybrid robots using this technique to demonstrate the wide range of capabilities this approach and hybridity can bring to soft robotics.

Correlations of Gelling Properties and 3D Printability to the Chemical Composition and Rheological Properties of Surimi from Different Marine Fish Species

Samples of marine surimi made from six different fish types have been comprehensively investigated and compared in terms of chemical composition, protease activity, gelling chemistry, gel properties and 3D printability. It has been found that surimi with high protein content, low fat concentration, low activity of endogenous protease (cathepsin B, cathepsin L, cathepsin D, calpain and serine protease) and low TVB-N showed better gelling capacity and gel properties. However, the 3D printability of surimi was more relevant to apparent viscosity. The surimi with viscosity between 5000 Pa·s and 12,000 Pa·s yielded better printing performance as indicated by higher printing accuracy than 97% and less cooking loss. This study clarified the effects of marine fish types on the corresponding surimi gelation and gel properties, and successfully established relationships between surimi properties and 3D printing performance, thus providing new insights on exploring new surimi sources and developing 3D surimi printing techniques.

Achieving Room‐Temperature Phosphorescence in Solution Phase from Carbon Dots Confined in Nanocrystals

Carbon dots (CDs) have attracted growing interest in the construction of room‐temperature phosphorescent (RTP) materials. However, in the solution phase of CDs, it is still challenging to obtain efficient and stable phosphorescent emission due to the intense quenching effect by dissolved oxygen and solvent molecules. Herein, we report robust phosphorescence in the solution phase, achieved by encapsulating citrate‐derived CDs into NaYF4 nanocrystals via a one‐step method of high‐temperature coprecipitation. Combined characterizations show that the triplet emission from CDs is related to the abundance of C=O in the CDs, the formation of ionic‐bond networks around the CDs, and the spatial confinement and quenching inhibition effects of NaYF4 nanocrystals. Notably, the transition of CDs@NaYF4 from hydrophobicity to hydrophilicity can be easily achieved by simple surface modulation of NaYF4 nanocrystals, which allows the RTP of CDs to be maintained in either polar or nonpolar solvents. In addition, CDs@NaYF4 exhibits stable afterglow in different pH environments, suggesting its excellent stability. Finally, we demonstrated the application of CDs@NaYF4 in 3D printing, oily anti‐counterfeiting patterns, and cell imaging. Our work can serve the controllable preparation of solution‐phase RTP materials and their various applications.

Achieving Room-Temperature Phosphorescence in Solution Phase from Carbon Dots Confined in Nanocrystals.

Carbon dots (CDs) have attracted growing interest in the construction of room-temperature phosphorescent (RTP) materials. However, in the solution phase of CDs, it is still challenging to obtain efficient and stable phosphorescent emission due to the intense quenching effect by dissolved oxygen and solvent molecules. Herein, we report robust phosphorescence in the solution phase, achieved by encapsulating citrate-derived CDs into NaYF4 nanocrystals via a one-step method of high-temperature coprecipitation. Combined characterizations show that the triplet emission from CDs is related to the abundance of C=O in the CDs, the formation of ionic-bond networks around the CDs, and the spatial confinement and quenching inhibition effects of NaYF4 nanocrystals. Notably, the transition of CDs@NaYF4 from hydrophobicity to hydrophilicity can be easily achieved by simple surface modulation of NaYF4 nanocrystals, which allows the RTP of CDs to be maintained in either polar or nonpolar solvents. In addition, CDs@NaYF4 exhibits stable afterglow in different pH environments, suggesting its excellent stability. Finally, we demonstrated the application of CDs@NaYF4 in 3D printing, oily anti-counterfeiting patterns, and cell imaging. Our work can serve the controllable preparation of solution-phase RTP materials and their various applications.

Additive Manufacturing: Prospects and Diverse Applications

Additive manufacturing (AM), also known as 3D printing, has emerged as a transformative technology in various industries, providing unprecedented design freedom and customized manufacturing solutions. This paper presents a detailed exploration of additive manufacturing applications in metallic materials, introducing the various types of additive manufacturing technologies, elucidating their fundamental principles, and summarizing current research endeavors. The manuscript offers insights into future directions and challenges in this rapidly evolving field, serving as a valuable resource for researchers and engineers aiming to harness the potential of additive manufacturing in advancing metallic materials.

Enhancing anatomy education using anatomical sign language: expanding its expressive capabilities to the upper and lower extremities, face, and brain structures.

Various information technologies have been introduced for anatomy education in the current digital era, including three-dimensional (3D) virtual reality, mobile augmented reality, and 3D printing. While these technologies enhance educational effectiveness, their high cost often restricts their accessibility. Conversely, low-cost methods using everyday items have proven effective in anatomy education. The anatomical sign language (ASL) method has been introduced, and uses the fingers, hands, and arms to represent anatomical structures to leverage muscle memory to aid the retention and understanding of complex anatomical structures and provide a comprehensive and interactive approach to anatomy education. This study was performed to expand ASL to include the expressive capabilities of the upper and lower extremities, and the face and brain. The results indicate that ASL effectively illustrates the anatomy of various structures. The educational benefits of ASL for anatomy and radiologic anatomy education are discussed.

A Scoping Review on Accuracy and Acceptance of 3D-Printed Removable Partial Dentures

This scoping review aims to provide comprehensive evidence on methods used to assess the accuracy and acceptance of three-dimensional (3D)-printed removable partial dentures (RPDs). An electronic search of English language literature from January 2014 to 2024 was performed on five databases, PubMed, Scopus, Web of Science, EMBASE, and Google Scholar, using MesH terms. The parameter of interest was extracted and presented in tabular form. Of 1025 retrieved studies, 35 studies were included in the final analysis. Most studies were laboratory-based, and clinical trials were conducted between 2018 and 2022 without a control group. The studies included the use of the stone model or duplication model as a reference, as well as the direct 3D printing method and polished frame for detecting the accuracy of fit. The assessment method was divided into two categories: (1) qualitative (visual and tactile method) and (2) quantitative assessment, which includes optical and computerized methods for assessing the accuracy of fit. Dentist perception and patient-related outcomes were evaluated to measure the acceptance of 3D-printed RPDs. In conclusion, patients’ satisfaction and dentists’ acceptance of digitally printed RPDs were greater than those of conventional ones. The quantitative method (mainly computerized) provides a more accurate and precise assessment to evaluate the accuracy of fit. It allows clinicians to detect minute changes that cannot be inspected with visual and optical methods.