3DP Technology Research Articles

3D Printing-Assisted Supramalleolar Osteotomy for Ankle Osteoarthritis.

Ankle osteoarthritis (OA) is an important factor that causes pain and dysfunction after ankle joint movement. In early and mid-term ankle OA, supramalleolar osteotomy can delay the progression of disease and maximize the preservation of ankle joint function. Three-dimensional printing (3DP) technology has brought us new hope, which can improve the accuracy of osteotomy, reduce the number of fluoroscopy, reduce the amount of blood loss, and achieve personalized and accurate treatment. The data of 16 patients with ankle OA in our center from January 2003 to July 2020 were retrospectively analyzed and divided into the 3DP group and the traditional group according to different treatment methods. Seven patients in the 3DP group used the 3DP personalized osteotomy guide; nine patients were treated by traditional osteotomy. All patients were followed up for 13.9 ± 3.1 months after the operation. The operation time in the 3DP group was 126.4 ± 11.1 min, its intraoperative blood loss was 85.7 ± 24.1 mL, and its intraoperative fluoroscopy time was 2.4 ± 0.2, which were all significantly less than 167.3 ± 12.2 min, 158.3 ± 22.8 mL, and 5.8 ± 0.2 times in the traditional group (P < 0.05), respectively. In the 3DP group, its postoperative tibial anterior surface (TAS) angle was 90.6 ± 0.3° and the talar tilt (TT) angle was 2.2 ± 0.6°, which were all significantly different compared with its preoperative data of 83.4 ± 1.7 and 8.0 ± 1.5°, respectively (P < 0.05). Compared with traditional osteotomy, 3DP-assisted supramalleolar osteotomy for varus and valgus ankle OA can significantly shorten the operation time and reduce intraoperative bleeding and the frequency of intraoperative fluoroscopy; personalized 3DP osteotomy guides and models can assist in the accurate correction of varus deformity during operation, restore the lower limb alignment, and improve the biomechanical status of the lower limbs. In addition, the 3DP of porous tantalum has good histocompatibility, and its interface structure and porosity are more conducive to bone ingrowth. For complex bone defects and revision prostheses, matching implants can be printed individually, which could realize the personalized precise treatment.

Rain Energy Harvesting Using Atomically Thin Gadolinium Telluride Decorated 3D Printed Nanogenerator

AbstractThe 3D printing (3DP) technology offers an innovative approach to developing energy storage devices to create facile and low‐cost customized electrodes for modern electronics. Generating electric potential by moving a droplet of ionic solution over 2D materials is a novel method for rain energy harvesting. This work demonstrates a liquid‐solid contact electrification‐based 3DP nanogenerator where raindrop passes through the positively charged ultrathin gadolinium telluride (Gd2Te3) sheets. The output efficiency of the nanogenerator is increased to ≈400% by enhancing the surface area of copious 3D‐printed porous structures. The density functional theory (DFT) calculations reveal that the high electrical conductivity of (112) surface of Gd2Te3 is due to the p‐type charge carriers, which help to generate electricity by interacting with the ionic solution. This work can open up a new avenue to advance scientific research on blue energy harvesting and tackle the energy crisis.

The fresh and hardened properties of 3D printing cement-base materials with self-cleaning nano-TiO2:An exploratory study

Cement-based 3D printing (3DP) is going deep into the traditional civil construction due to its advantages, such as saving materials, reducing carbon dioxide emissions and lowering energy requirements. However, the printability of 3DP mortars is the main factor restricting the rapid development of cement-based 3DP technology. The nano-TiO2 (NT) performs obviously self-cleaning effect and has potential merit in improving the printability in cement-based 3DP as an additive. In this study, the printing pastes with different NT dosages and water-cement ratios are designed to reveal the fresh and hardened properties of cement-based 3DP. The test results show that NT has better thickening property and can shorten the setting time, thus reducing the slump and flow diameter. What's more, appropriate NT content can increase the static yield stress of pastes, and reduce the dynamic yield stress and plastic viscosity of pastes at the same time. The mortar with 3% NT dosage has better buildability, compared with undoped NT group, the deformation-rate of the sample increases by 32.4% and the inclination-rate decreases by 52.7%. The mortar with 3% NT dosage also has better density and compressive strength, compared with undoped NT group, the dry density increases by 19.6% and the compressive strength increases by 51.6%. Moreover, the results also indicated that when the water-cement ratio of paste is smaller, its fluidity is smaller, and its static yield stress, dynamic yield performance as well as plastic viscosity are higher. Micro-pores and hydration products of 3DP samples tested by SEM and XRD showed that the NT can refine the pore structure and reinforce the compactness of the mixtures, and the self-cleaning test verified that NT also had obvious self-cleaning performance for cement-based printed samples, which indicates the NT is an ideal 3DP cement additive for clean production and green development in civil construction.

Mechanical and energy absorption behaviors of 3D printed continuous carbon/Kevlar hybrid thread reinforced PLA composites

Over the last few years, three-dimensional printing(3DP) technology has evolved to incorporate composite materials. However, using material extrusion (ME) technology, it is still difficult to improve the stiffness with stable elongation and energy absorption of continuous fiber reinforced composites at the same time. This study aimed to 3D print hybrid threads by merging several types of continuous Kevlar and Carbon fibers. Which were created using material extrusion 3D printing to accomplish cooperative ductility and brittleness augmentation. To analyze the mechanical performance and reveal the failure and deformation mechanisms, tension tests, three-point bending tests, and drop hammer impact tests were performed. The proposed hybrids have substantially greater flexural modulus, flexural strength, tension modulus, and tension strengths with absorbed energies than standard single type fiber composites. Crack resistance during impact test of hybrid composites was enhanced by over 91% compared to carbon fiber non-hybrid composites. SEM images of hybrid specimens provided an insight of the failure mechanisms, resulting in stable hybrid composites. Positive hybrid effect further demonstrates its great energy absorption capacity.

3D Printing in Sustainable Buildings: Systematic Review and Applications in the United Arab Emirates

Three-dimensional printing (3DP) has been rapidly evolving to be one of the leading technology fields in the coming decades. However, as in the early years of new technologies, 3DP suffers from technical limitations and various implications. This study focuses on the applications of 3DP in the construction industry, emphasizing its environmental, financial, and social sustainability aspects. A systematic bibliographic analysis was carried out for the relevant publications which increased by 25-fold from 2014 to 2021. The 3D-printed construction projects in the United Arab Emirates (UAE) are presented to demonstrate the early 3DP technology penetration into its booming construction sector. The UAE case is of particular interest from a sustainability perspective due to the environmental footprint of the ample construction activities in the country, combined with the ambitious strategic plans to achieve sustainable development goals. This critical analysis shows that, despite the limited literature, 3DP could potentially be a sustainable alternative with up to 49% less environmental footprint and 78% more cost-effectiveness compared to conventional construction techniques. As the social sustainability aspect was the least addressed, this study discusses relevant social impact indicators and systematic assessment criteria. It is evident that 3DP is already reshaping the future of the built environment, especially in cases where 3DP is advantageous, such as customized designs, quick project delivery, and sustainability-oriented constructions.

Assessment of the adoption of 3D printing technology for construction delivery: A case study of Lagos State, Nigeria

The innovative solutions offered by integrating 3D printing technology in construction over the conventional practices have established its globally rising adoption in the construction industry. This study assessed the awareness, application, drivers, and barriers to adopting enhanced 3D printing technology for construction to enhance faster and more sustainable construction processes. The study adopted a quantitative descriptive analysis which was based on primary data. The primary data were obtained using structured questionnaires self-administered to construction firms/contractors in Lagos State, Nigeria. Data collected were analyzed using descriptive and inferential statistics. The study established that the awareness and application levels of the technology are still deficient, as the vast majority (80.8%) of the firms who had an awareness of the technology in the study area acquired it through personal research and professional dialogue, rather than through the practical application of the technology. This finding showed that 3DP technology is a new construction option in the study area. The findings showed statistically significant differences among the drivers (0.039≤ p ≤0.017) for the adoption of 3D printing technology, which is influenced by the client’s demand and desire. The study further established that inadequate power source is a significant limiting factor to adopting 3D printing in the study area. Implications are indicated by the findings on the technology drivers and barriers that could help the construction industry in developing countries towards capability improvement for better adoption of 3D printing innovation and enhanced sustainable construction process.

Tissues and organ printing: An evolution of technology and materials.

Since its beginnings, three-dimensional printing (3DP) technology has been successful because of ongoing advances in operating principles, the range of materials and cost-saving measures. However, the 3DP technological progressions in the biomedical sector have majorly taken place in the last decade after the evolution of novel 3DP systems, generally categorised as bioprinters and biomaterials to provide a replacement, transplantation or regeneration of the damaged organs and tissue constructs of the human body. There is now substantial scientific literature accessible to support the benefits of digital healthcare procedures with the help of bioprinters. It is of the highest significance to know the fundamental principles of the available printers and the compatibility of biomaterials as their feedstock, notwithstanding the huge potential of bioprinting systems to manufacture organs and other human body components. This paper provides a precise and helpful reading of the different categories of bioprinters, suitable biomaterials, numerical simulations and modelling and examples of much acknowledged clinical practices. The paper will also cite the prominent issues that still have not received desired solutions. Overall, the article will be of great use for all the professionals, scholars and engineers concerned with the 3DP, bioprinting and biomaterials.

Accuracy of anatomic 3-dimensionally printed canine humeral models.

To evaluate the accuracy of various three-dimensional print (3DP) technologies using morphometric measurements. Experimental. Cadaveric canine humeri and size-matched 3DP models. Fiduciary radiopaque markers were affixed to canine humeri of three different sizes (4, 13, 29 kg) at predetermined anatomical landmarks. 3DP models were created using one of three printers; desktop printers Form 3L and Ultimaker 5S, and industrial printer Objet Connex (n=5/group/printer). Marker based morphometric dimensions between cadavers and 3DP models were statistically compared using 2-factor repeated measures ANOVA followed by Tukey's post-hoc test (p < .05). Bone size and printer type both significantly affected 3DP accuracy, with size having the larger effect (p < .0001 and p < .02, respectively). Regardless of printing technology, model size was smaller than native bone in most cases. At the humeral condylar level, the best accuracy was seen in the medium-sized humerus with the Ultimaker printer ([0.09 mm], p < .03). Accuracy was reduced in the proximal humerus in all groups. Desktop printers were overall more accurate than the industrial printer. Although significant differences were identified between models of different sizes, the submillimetric magnitude of these differences is unlikely to be clinically relevant. While preoperative planning using 3DP models is becoming mainstream, accurate representation of the actual bone is critical. This study demonstrates that common desktop printers are suitable for this purpose.

Translational design for limited resource settings as demonstrated by Vent-Lock, a 3D-printed ventilator multiplexer

BackgroundMechanical ventilators are essential to patients who become critically ill with acute respiratory distress syndrome (ARDS), and shortages have been reported due to the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).MethodsWe utilized 3D printing (3DP) technology to rapidly prototype and test critical components for a novel ventilator multiplexer system, Vent-Lock, to split one ventilator or anesthesia gas machine between two patients. FloRest, a novel 3DP flow restrictor, provides clinicians control of tidal volumes and positive end expiratory pressure (PEEP), using the 3DP manometer adaptor to monitor pressures. We tested the ventilator splitter circuit in simulation centers between artificial lungs and used an anesthesia gas machine to successfully ventilate two swine.ResultsAs one of the first studies to demonstrate splitting one anesthesia gas machine between two swine, we present proof-of-concept of a de novo, closed, multiplexing system, with flow restriction for potential individualized patient therapy.ConclusionsWhile possible, due to the complexity, need for experienced operators, and associated risks, ventilator multiplexing should only be reserved for urgent situations with no other alternatives. Our report underscores the initial design and engineering considerations required for rapid medical device prototyping via 3D printing in limited resource environments, including considerations for design, material selection, production, and distribution. We note that optimization of engineering may minimize 3D printing production risks but may not address the inherent risks of the device or change its indications. Thus, our case report provides insights to inform future rapid prototyping of medical devices.

Fused Deposition Modeling PEEK Implants for Personalized Surgical Application: From Clinical Need to Biofabrication.

Three-dimensional printing (3DP) technology is suitable for manufacturing personalized orthopedic implants for reconstruction surgery. Compared with traditional titanium, polyether-ether-ketone (PEEK) is the ideal material for 3DP orthopedic implants due to its various advantages, including thermoplasticity, thermal stability, high chemical stability, and radiolucency suitable elastic modulus. However, it is challenging to develop a well-designed method and manufacturing technique to meet the clinical needs because it requires elaborate details and interplays with clinical work. Furthermore, establishing surgical standards for new implants requires many clinical cases and an accumulation of surgical experience. Thus, there are few case reports on using 3DP PEEK implants in clinical practice. Herein, we formed a team with a lot of engineers, scientists, and doctors and conducted a series of studies on the 3DP PEEK implants for chest wall reconstruction. First, the thoracic surgeons sort out the specific types of chest wall defects. Then, the engineers designed the shape of the implant and performed finite element analysis for every implant. To meet the clinical needs and mechanical requirements of implants, we developed a new fused deposition modeling technology to make personalized PEEK implants. Overall, the thoracic surgeons have used 114 personalized 3DP PEEK implants to reconstruct the chest wall defect and further established the surgical standards of the implants as part of the Chinese clinical guidelines. The surface modification technique and composite process are developed to overcome the new clinical problems of implant-related complications after surgery. Finally, the major challenges and possible solutions to translating 3DP PEEK implants into a mature and prevalent clinical product are discussed in the paper.

3D printing in palliative medicine: systematic review

BackgroundThree-dimensional printing (3DP) enables the production of highly customised, cost-efficient devices in a relatively short time, which can be particularly valuable to clinicians treating patients with palliative care intent who...

Additive manufacturing technology in mining engineering research

AbstractNowadays, additive manufacturing, or 3D printing (3DP), though not a new technology in many industrial fields, is still relatively novel in mining engineering. This study explored the application of 3D metal printing, 3D polylactic acid/acrylonitrile butadiene styrene printing, and 3D concrete printing in coal mining. Some examples of physical models established via 3DP technologies were studied in detail, namely, 3DP bolts, 3DP steel ladder beams, 3DP face plates, and 3DP metal arches, which were installed in scaled 3DP concrete prototype models of coal mine excavation. Through the comprehensive laboratory loading tests, the models could simulate the damage scenario highly similar to the real failures. The results show that the 3D printed physical models greatly improved the accuracy and reliability of experiments. On this basis, the conceptual design of a 3DP machine for physical models was proposed, which had the potential of resembling the strata deformation/collapse in natural scenarios. Through assessing the applicability of the additive manufacturing technology in mining engineering, this study aimed to further explore its potential applicability in other engineering contexts such as slope controlling, large underground engineering, and underground space stability.

3D Printing, Intellectual Property Rights and Medical Emergencies: In Search of New Flexibilities

The COVID-19 pandemic has exponentially accelerated the use of 3D printing (3DP) technologies in healthcare. Surprisingly, though, we have seen hardly any public intellectual property right (IPR) disputes concerning the 3D-printed medical equipment produced to cope with this crisis. Yet it can be assumed that a great variety of IPRs could potentially have been enforced against the use of various items of equipment printed out without express consent from IP holders. Many reasons might have motivated IP owners not to enforce their rights during the pandemic, such as the fear of acquiring a bad reputation during a declared situation of national emergency. There is no internationally recognised general exception to IPR enforcement for health emergencies, while several − sometimes ineffective − tools, like compulsory licensing, voluntary licensing arrangements and potential TRIPS waivers, have been considered or used to facilitate access to and the distribution of innovations in critical situations. During the COVID-19 emergency, this has meant that the 3DP community has been operating in a state of relative uncertainty including with regard to the risks of IP infringement. This study contextualises these issues for pandemic-relevant 3DP. Building upon experience gathered during the COVID-19 pandemic, we look to the future to see what novel mechanisms within the IPR system could provide the additional flexibility required for dealing more smoothly, with the help and support of digital technologies, with situations such as global health emergencies.

Viscoelastic and thixotropic characterization of paraffin/photopolymer composites for extrusion-based printing

Three-dimensional printing (3DP) of functional materials is increasingly important for advanced applications requiring objects with complex or custom geometries or prints with gradients or zones with different properties. A common 3DP technique is direct ink writing (DIW), in which printable inks are comprised of a fluid matrix filled with solid particles, the latter of which can serve a dual purpose of rheology modifiers to enable extrusion and functional fillers for performance-related properties. Although the relationship between filler loading and viscosity has been described for many polymeric systems, a thorough description of the rheological properties of three-dimensional (3D) printable composites is needed to expedite the creation of new materials. In this manuscript, the relationship between filler loading and printability is studied using model paraffin/photopolymer composite inks containing between 0 and 73 vol. % paraffin microbeads. The liquid photopolymer resin is a Newtonian fluid, and incorporating paraffin microbeads increases the ink viscosity and imparts shear-thinning behavior, viscoelasticity, and thixotropy, as established by parallel plate rheometry experiments. Using Einstein and Batchelor's work on colloidal suspension rheology, models were developed to describe the thixotropic behavior of inks, having good agreement with experimental results. Each of these properties contributes to the printability of highly filled (≥43 vol. % paraffin) paraffin/photopolymer composite inks. Through this work, the ability to quantify the ideal rheological properties of a DIW ink and to selectively control and predict its rheological performance will facilitate the development of 3D printed materials with tunable functionalities, thus, advancing 3DP technology beyond current capabilities.

The Role of Digital-Media-Based Pedagogical Aids in Elementary Entomology: An Innovative and Sustainable Approach

It has been challenging for city school pupils to learn about insects, given the lack of live insects. To overcome this challenge, the objective of this study is to propose the use of emerging digital media, namely three-dimensional printing (3DP) technologies, to create reusable, fake, “live” insects. In this study, we designed two 3D-printed pedagogical aids to support elementary entomology. The first aid was a set of cards showing photos of the 3D-printed insect prototype, which could help the learners in close observation of the insect body’s regions and parts, and the second 3D-printed aid was a construction kit mimicking physical insects, which were made of an enlarged 3D-printed insect prototype. The two aids were used in our field experiment to examine the effectiveness in learning and motivation. A total of 153 pupils were grouped into three groups (one using the existing multimedia e-book, one using the first 3DP aid, and one using the second aid). The results confirm that the digital media application—in this case, 3DP technologies—were able to compensate for the lack of the live insects. These results raised our confidence in using a customized size 3D-printed insect prototype to enhance rudimentary entomology inside the classroom. If the 3DP technologies are used properly, they could offer an innovative and sustainable solution.

Value of 3D printing technology combined with indocyanine green fluorescent navigation in complex laparoscopic hepatectomy.

Laparoscopic hepatectomy (LH) has achieved rapid progress over the last decade. However, it is still challenging to apply laparoscopy to lesions located in segments I, VII, VIII, and IVa and the hepatic hilar region due to difficulty operating around complex anatomical structures. In this study, we applied three-dimensional printing (3DP) and indocyanine green (ICG) fluorescence imaging technology to complex laparoscopic hepatectomy (CLH) to explore the effects and value of the modified procedure. From January 2019 to January 2021, 54 patients with complex hepatobiliary diseases underwent LH at our center. Clinical data were collected from these patients and retrospectively analyzed. A total of 30 patients underwent CLH using the conventional approach, whereas 24 cases received CLH with 3DP technology and ICG fluorescent navigation. Preoperative data were compared between the two groups. In the 3DP group, we modified the surgical strategy of four patients (4/24, 16.7%) due to real-time intraoperative navigation with 3DP and ICG fluorescent imaging technology. We did not modify the surgical strategy for any patient in the non-3DP group (P = 0.02). There were no significant differences between the non-3DP and 3DP groups regarding operating time (297.7±104.1 min vs. 328.8±110.9 min, P = 0.15), estimated blood loss (400±263.8 ml vs. 345.8±356.1 ml, P = 0.52), rate of conversion to laparotomy (3/30 vs. 2/24, P = 0.79), or pathological outcomes including the incidence of microscopical R0 margins (28/30 vs. 24/24, P = 0.57). Additionally, there were no significant differences in postoperative complications or recovery conditions between the two groups. No instances of 30- or 90-day mortality were observed. The optimal surgical strategy for CLH can be chosen with the help of 3DP technology and ICG fluorescent navigation. This modified procedure is both safe and effective, but without improvement of intraoperative and short-term outcomes.

Modification effect of nanosilica and polypropylene fiber for extrusion-based 3D printing concrete: Printability and mechanical anisotropy

Recently cement-based 3D printing (3DP) technology has been broadly adopted in civil engineering, and its printability is an important factor for its further application. Taking cement, fine sand and thickener as the basic formula, hybrid nanosilica (NS) and polypropylene (PP) fibers with different dosages are tested to comparing their modification effects on 3DP concrete’s printability and mechanical anisotropy. The mortar flowability, printability, physical-mechanical properties and microstructure of these modified 3DP concretes are tested. The results demonstrated that both NS and PP fibers can accelerate the setting time of mortar, reduce its paste fluidity and slump, and improve its printability and homogeneity. But its density and compressive strength are reduced. Specifically, adding 1% NS and 0.2% PP fibers to 3DP concrete can improve its buildability by more than 67%, reduce the deformation rate up to 46% and the anisotropy of compressive strength up to 64%. These additive material also make the structure change from brittle failure to ductile failure, which is beneficial to structural safety. The microstructure analysis of these presented 3DP concrete shows that the NS can increase the number of concrete’s micro pores and improve both its pore structure and the cementation property between layers, which can enhance the cementation between PP fibers and cement paste. These results can enrich the 3D-printed cement construction in additive manufacturing.

Point of Care Virtual Surgical Planning and 3D Printing in Facial Feminization Surgery.

The use of virtual surgical planning (VSP) and three-dimensional printing (3DP) technologies in the routine facial feminization surgery practice has gained a significant popularity over the past few years. The clinical applications of them are claimed to improve safety, accuracy, and efficiency of facial feminization surgeries. In this article, we review and discuss the current applications of VSP and 3DP in different facial feminization procedures.

3D and 4D Printing in the Fight against Breast Cancer.

Breast cancer is the second most common cancer worldwide, characterized by a high incidence and mortality rate. Despite the advances achieved in cancer management, improvements in the quality of life of breast cancer survivors are urgent. Moreover, considering the heterogeneity that characterizes tumors and patients, focusing on individuality is fundamental. In this context, 3D printing (3DP) and 4D printing (4DP) techniques allow for a patient-centered approach. At present, 3DP applications against breast cancer are focused on three main aspects: treatment, tissue regeneration, and recovery of the physical appearance. Scaffolds, drug-loaded implants, and prosthetics have been successfully manufactured; however, some challenges must be overcome to shift to clinical practice. The introduction of the fourth dimension has led to an increase in the degree of complexity and customization possibilities. However, 4DP is still in the early stages; thus, research is needed to prove its feasibility in healthcare applications. This review article provides an overview of current approaches for breast cancer management, including standard treatments and breast reconstruction strategies. The benefits and limitations of 3DP and 4DP technologies are discussed, as well as their application in the fight against breast cancer. Future perspectives and challenges are outlined to encourage and promote AM technologies in real-world practice.

Lowering the curing shrinkage of epoxy acrylate‐based photosensitive resins through nano‐TiO2 particle with surface grafted by thiol‐terminated hyperbranched polymer

AbstractUV curing three‐dimensional printing (3DP) technology has been developing rapidly due to its high molding accuracy and low cost. However, the curing shrinkage rate of the existing UV curing 3DP materials is still high. The use of inorganic particles to reduce the curing shrinkage of 3D printing materials has received more and more attention in recent years, but the poor dispersibility of inorganic particles in the photosensitive resins has not been effectively solved. In this paper, nano‐TiO2 particles were treated by KH570 in advance and the surface of which were grafted by thiol‐terminated hyperbranched polymer (THBP), hereby THBP@TiO2 was obtained. The results showed that by incorporating of 5 wt% THBP@TiO2, the volume shrinkage rate of epoxy acrylate (EA)‐based photosensitive resins decreased from 8.95% to 4.18%. The THBP@TiO2 combined the anti‐shrinkage mechanism of thiol‐based hyperbranched polyester with that of and inorganic nanoparticles. Otherwise, surface grafting of THBP may effectively improve the dispersibility of nano‐TiO2 particles in EA‐based photosensitive resin by reducing the nano‐TiO2 particles surface energy, and increase the load transfer capacity. The impact strength of 5 wt% THBP@TiO2 modified photosensitive resin increased from 11.2 to 18.1 kJ/m2.