3D Additive Manufacturing Technologies Research Articles

The Impact of 3D Printing Technology on the Improvement of External Wall Thermal Efficiency—An Experimental Study

Three-dimensional printing technology continues to evolve, enabling new applications in manufacturing. Extensive research in the field of biomimetics underscores the significant impact of the internal geometry of building envelopes on their thermal performance. Although 3D printing holds great promise for improving thermal efficiency in construction, its full potential has yet to be realized, and the thermal performance of printed building components remains unexplored. The aim of this paper is to experimentally examine the thermal insulation characteristics of prototype cellular materials created using 3D additive manufacturing technologies (SLS and DLP). This study concentrates on exploring advanced thermal insulation solutions that could enhance the energy efficiency of buildings, cooling systems, appliances, or equipment. To this end, virtual models of sandwich composites with an open-cell foam core modeled after a Kelvin cell were created. They were characterized by a constant porosity of 0.95 and a pore diameter of the inner core of the composites of 6 mm. The independent variables included the different material from which the composites were made, the non-uniform number of layers in the composite (one, two, three, and five layers) and the total thickness of the composite (20, 40, 60, 80, and 100 mm). The impact of three independent parameters defining the prototype composite on its thermal insulation properties was assessed, including the heat flux (q) and the heat transfer coefficient (U). According to the experimental tests, a five-layer composite with a thickness of 100 mm made of soybean oil-based resin obtained the lowest coefficient with a value of U = 0.147 W/m2·K.

Morphology analysis and process optimization of μ-SLA 3D manufactured micro-nano conic structure

PurposeThis paper is devoted to prepare micro-cone structure with variable cross-section size by Stereo Lithography Appearance (SLA)-based 3D additive manufacturing technology. It is mainly focused on analyzing the forming mechanism of equipment and factors affecting the forming quality and accuracy, investigating the influence of forming process parameters on the printing quality and optimization of the printing quality. This study is expected to provide a µ-SLA surface preparation technology and process parameters selection with low cost, high precision and short preparation period for microstructure forming.Design/methodology/approachThe µ-SLA process is optimized based on the variable cross-section micro-cone structure printing. Multi-index analysis method was used to analyze the influence of process parameters. The process parameter influencing order is determined and validated with flawless micro array structure.FindingsAfter the optimization analysis of the top diameter size, the bottom diameter size and the overall height, the influence order of the printing process parameters on the quality of the micro-cone forming is: exposure time (B), print layer thickness (A) and number of vibrations (C). The optimal scheme is A1B3C1, that is, the layer thickness of 5 µm, the exposure time of 3000 ms and the vibration of 64x. At this time, the cone structure with the bottom diameter of 50 µm and the cone angle of 5° could obtain a better surface structure.Originality/valueThis study is expected to provide a µ-SLA surface preparation technology and process parameters selection with low cost, high precision and short preparation period for microstructure forming.

A NEW BIO-INSPIRED WING DESIGN WITH 3D ADDITIVE MANUFACTURING SCANNING AND PRINTING METHOD: MJF TECHNOLOGY

In this study, unlike many wing profiles currently available, a new wing design has been carried out with bio-inspiration, which has attracted the attention of many scientists. There are many traditional methods in 3d additive manufacturing technologies. There are several types of 3D printing method. The four most preferred 3d printing methods are as follows. Fused Deposition Modeling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS), Multi Jet Fusion (MJF). MJF technology, one-to-one prototype production of wings with very small dimensions and aerodynamic structure has been achieved. In contrast to FDM and other additive printing technologies, it is possible to eliminate highly sensitive and high surface quality products.

Photo-assisted ultrasonic curing for ultrafast and deep prototyping based on coumarin derivatives

Although photocuring is currently the most commonly used method in 3D additive manufacturing, it still faces significant challenges in rapid prototyping of thick materials due to the limited penetration of light. Ultrasonic technology has the advantages of high penetration depth and unparalleled cavitation, offering opportunities for enabling additive manufacturing of thick materials. In this study, a coumarin-based two-component system composed of Coum-Ph-OC12H25 and N-phenylglycine as initiator and hydrogen supplier, respectively, was developed to achieve ultrasonic curing of tripropylene glycol diacrylate (TPGDA). The ideal curing efficiency of this two-component system was optimized to 90 %, and ultrasonic curing of thick materials was achieved with a penetration depth of up to 15 cm. Moreover, electron spin resonance (ESR) spectroscopic measurements demonstrated the free-radical reaction mechanism. It is believed that this research has the potential to expand the 3D additive manufacturing technology and pave the way for future developments in this field.

First of its kind: a test artifact for direct laser writing

With femtosecond-laser direct writing (fs-LDW) maturing in all aspects as a manufacturing technology, a toolset for quality assurance must be developed. In this work we introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric features to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. selective laser melting. The test artifact introduced in this work was developed in particular to accommodate (1) the high geometrical resolution of fs-LDW structures and (2) the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal Raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our fs-LDW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresists, laser power and scanning speed and to analyze the geometric accuracy of a structure produced using these guidelines. The shown test artifact is publicly available as STL file on GitHub (https://github.com/BAMresearch/2PP-TestArtifact) and in the supplement.

3D bioprinting in airway reconstructive surgery: A pilot study

ObjectivesOpen surgery is a reliable choice for congenital subglottic stenosis, that represents the third most common congenital anomaly of the larynx. One of the procedures performed is anterior laryngotracheal reconstruction (LTR) with anterior rib graft. The objective of this preliminary study was to evaluate the potential of 3D printing technology for the realization of laryngo-tracheal scaffold in Polycaprolactone (PCL) implanted in vivo in ovine animal model. MethodsA 3D computer model of a laryngeal graft and a tracheal graft was designed and printed with PCL through 3D additive manufacturing technology. The scaffolds were seeded with autologous mesenchymal stem cells and cultured in vitro for up to 14 days. Anterior graft LTR with 3D printed scaffolds was performed on 5 sheep. The animals underwent endoscopic examinations at the first, 3rd, 6th, and 12th weeks after surgery and before sacrifice. The integration of the material was evaluated by the pathologist. ResultsTwo animals showed a favourable postoperative course and were sacrificed at 6 months postoperatively. In these cases, we observed endoscopically a complete integration of the cellularized PCL scaffold into the peri-implant tissues, and the pathologist found the growth of respiratory epithelium on the scaffold's inner surface. Other two animals showed a difficult post-operative recovery characterized by respiratory distress resulting in early sacrifice on postoperative days 31 and 33. In these animals we found a poor integration of the grafts into the tracheal structure, and a better integration of the laryngeal scaffold. The last animal developed a wound abscess and was sacrificed 80 days after surgery. We observed, in this case, a poor scaffold integration and an acute inflammatory reaction. ConclusionsFrom the preliminary data obtained we found that the excessive stiffness of the material, along with the anatomical features of the sheep, is a major limitation of this study. It will be necessary in the future to create a new biocompatible, more flexible and elastic graft, to achieve greater integration into surrounding tissues. Bioconstructed grafts could simplify surgery for the treatment of laryngo-tracheal stenosis, particularly in the treatment of long tracheal stenoses, which have, at the moment, very complex surgical options. Level of evidenceNA.

The use of 3D additive manufacturing technology in autogenous dental transplantation

BackgroundIn medicine and dentistry, 3D technology allows the virtual planning and printing of surgical replicas of anatomical structures that can facilitate certain transplant procedures. In dentistry, 3D technology is useful in autogenous tooth transplantation.Case presentationWe present a clinical case of an ectopic mandibular second premolar, describing the preoperative planning with dental replicas and the autotransplantation surgery. 3D prints of the surgical replica of the tooth to be transplanted was made using an Objet30 Prime® Printer, PolyJet. Clinical controls performed at 3, 6 and 12 months indicated the satisfactory evolution of the transplanted tooth.Conclusion3D additive manufacturing technology allows the preparation of a new recipient socket with the aid of a surgical replica of the tooth to be transplanted, thus minimizing handling and extraoral time.

Mechanical characterisation of anisotropic silica sand/furan resin compound induced by binder jet 3D additive manufacturing technology

Binder jet 3D printing of ceramic materials is an additive manufacturing technology that enables the production of complex and multi-functional parts through the selective jet binding of precursor powder beds. The present study makes use of the 3D Sand Printing (3DSP) process to create moulds and cores in the casting industry. The use of the 3DSP components as functional parts in industrial production is limited due to the uncertainty associated with their mechanical properties, such as their permeability and thermal stability. Moreover, because of the porous nature of their printed structures, their mechanical properties are dispersed and rather difficult to reproduce. This study aims to characterise the impact of different printing parameters on the mechanical performance of printed parts. For this purpose, a specific device was made in order to assess the mechanical characteristics of samples printed via this technique. The effects of processing parameters such as the printing orientation and building direction on the compressive properties of the printed specimens have also been carefully studied. Microstructural analyses were performed to better understand the relationship between the 3DSP process and the mechanical properties of the components produced from it. The results show that the mechanical tests carried out significantly improve the property reproducibility of the samples made using this technique.

Microstructure and mechanical properties of AI/Fe micro-laminated composites fabricated by ultrasonic consolidation

Ultrasonic consolidation technology is a new method for preparing high-performance laminate composite materials. This rapid consolidation additive manufacturing technology provides a new idea for the integration of complementary functional laminated composite structures. It has great potential for preparation of new generation of complex laminated composite parts, broadening the application field of laminated composite material, and means an advanced 3D additive manufacturing technology for materials and structures. In this paper, it is aimed at Al/carbon steel and Al/Fe laminated composites systems with low cost and multilayer structures, Al/carbon steel and Al/Fe laminated composite samples were consolidated by ultrasonic consolidation process. And the Al/carbon steel and Al/Fe interfacial bonding were studied by SEM and EDS. The hardness and tensile properties of laminated composites were tested by mechanical properties together with the fracture morphology of each interface was studied.

Preparation of biodegradable PLA/PCL composite filaments: effect of PLA content on strength

As one of the predominant 3D additive manufacturing technology, fused deposition modeling (FDM) suffers from the rich printable filaments. The goal of this paper is to produce a fully biodegradable polymeric composite filament by blending polylactic acid (PLA) with polycaprolactone (PCL). The effect of PCL content on the geometry, size, roughness and ultimate tensile stress of PLA/PCL composite filaments was investigated, and mechanical properties of the printed components were tested. The results indicate that, with the increase of PCL content, the diameter and ultimate tensile stress gradually decreased, while the surface roughness gradually increased. Due to the toughing effect, with an increase in PCL content, the tensile strength of parts decreased, while the elongation at break and the impact strength kept rising. It was found the parts printed with the addition of 20% of PCL composite filament exhibits the optimal comprehensive performance.

Novel rotating-vibrating magnetic abrasive polishing method for double-layered internal surface finishing

Components with complex internal surfaces are increasingly important for gas and fluid flow applications in aerospace and automotive industries. Recently, as an emerging manufacturing technology, three-dimensional (3D) additive manufacturing (AM) technology enables one-step fabrication of these complex internal surfaces. Although 3D AM technology eliminates the need for complex assembly process, due to the poor surface and sub-surface integrity, achieving a favourable surface condition is challenging. Therefore, a post-polishing process is essential for these 3D AM complex internal surfaces. This paper presents a novel rotating-vibrating magnetic abrasive polishing method to finish a kind of complex internal surface which has a double-layered tube structure made by selective laser melting (SLM) of Inconel 718. The principle of the method was illustrated and the material removal process was modelled. The feasibility of the method was verified and the surface evolution mechanism under different motions was revealed. The effects of process parameters on material removal and surface quality were evaluated quantitatively. The results showed that material was uniformly removed from both of the external surface of inner tube and internal surface of outer tube. The uneven surface caused by partially melt powders during SLM process was smoothed and the surface roughness was reduced from about 7 μm Ra to less than 1 μm Ra. Relatively higher material removal efficiency and lower surface roughness were obtained through combining rotation and vibration motions. The surface quality was improved representing by the increase of surface nanohardness and release of residual stress after polishing. There was no subsurface deformation and damage observed so that a damage-free surface was obtained.

3D Metal Printing - Additive Manufacturing Technologies for Frameworks of Implant-Borne Fixed Dental Prosthesis.

An edentulous patient was rehabilitated with maxillary metal-ceramic and mandibular metal-resin implant-supported fixed dental prosthesis (FDP). Metal frameworks of the FDPs were fabricated using 3D additive manufacturing technologies utilizing selective laser melting (SLM) and electron beam melting (EBM) processes. Both SLM and EBM technologies were employed in combination with computer numerical control (CNC) post-machining at the implant interface. This report highlights the technical and clinical protocol for fabrication of FDPs using SLM and EBM additive technologies.

3D model of filler melting with micro-beam plasma arc based on additive manufacturing technology

Additive manufacturing technology is a systematic process based on discrete-accumulation principle, which is derived by the dimension of parts. Aiming at the dimension mathematical model and slicing problems in additive manufacturing process, the constitutive relations between micro-beam plasma welding parameters and the dimension of part were investigated. The slicing algorithm and slicing were also studied based on the dimension characteristics. By using the direct slicing algorithm according to the geometric characteristics of model, a hollow thin-wall spherical part was fabricated by 3D additive manufacturing technology using micro-beam plasma.

Implementation of A Photo-Curable 3D Additive Manufacturing Technology with Coloring Gray Capability by Using Piezo Ink-Jet

Implementation of A Photo-Curable 3D Additive Manufacturing Technology with Coloring Gray Capability by Using Piezo Ink-Jet

Combining X-ray CT and 3D printing technology to produce microcosms with replicable, complex pore geometries

Measurements in soils have been traditionally used to demonstrate that soil architecture is one of the key drivers of soil processes. Major advances in the use of X-ray Computed Tomography (CT) afford significant insight into the pore geometry of soils, but until recently no experimental techniques were available to reproduce this complexity in microcosms. This article describes a 3D additive manufacturing technology that can print physical structures with pore geometries reflecting those of soils. The process enables printing of replicated structures, and the printing materials are suitable to study fungal growth. This technology is argued to open up a wealth of opportunities for soil biological studies.