Papers by Keyword: 3D Printing

Abstract: This study investigates the possibility of designing and creating dynamic facades of buildings located in aggressive climatic environments (temperatures, air currents, brightness etc.). The study is based on EN AW-5754 samples manufactured by U bending, representing the modules for dynamic facades. The bending process uses a 300 kN Abkant type press. ​ It is performed along two curved lines. The punch and the related mold are printed from ABS with FDM (fused deposited material) technology. Bending is facilitated by customized slots in 4 laser-cut patterns placed along the bending lines. The paper aims to analyze the influence of the slot patterns on the U-bending process, respectively the design of the mold and the punch designed and executed by 3D printing technology.

Abstract: The paper presents a research object of a portal realized using the method of 3D printing of cement composite. The object serves as an experimental portal redefining the relationship between a building element and ornament. The form of the portal is generated by a Möbius transformation of part of the load-bearing wall. This transformation allows the basic structural logic of the wall to be converted into an ornamental layer without losing material logic and continuity. The load-bearing material of the object is a cement composite, optimized for robotic printing without formwork. Printing enabled the production of complex elements with high geometric precision. Thanks to digital control, the shape can be deconstructed into a precise printing trajectory, eliminating the human factor and streamlining production even for complex segments. The resulting object combines the structural and visual roles of the elements without the need for secondary division into load-bearing and aesthetic parts. The aim of the research is to verify the possibilities of robotic printing in the production of architectural elements from cement composite that transcend the traditional dichotomy of structure and decoration. The process shows that even highly individualized elements can be produced efficiently, repeatedly, and with material savings. Special attention is paid to detailed parameterization of the mold, surface quality, and layering during printing, which fundamentally affects the resulting mechanical and aesthetic properties. The paper offers a practical view of the application of robotic 3D concrete printing in architectural and engineering applications and its potential for transforming current construction approaches.

Abstract: PLA is a common, eco-friendly polymer for FDM printing. The infill patterns and densities play a significant role in determining the mechanical properties of three-dimensional (3D) printed PLA. In this work, two different infill patterns (Concentric and Rectilinear) and infill densities (30% and 100%) were printed. PLA filaments were characterized using Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and Scanning Electron Microscopy analysis (SEM) techniques. The tensile test results revealed that the 100% concentric pattern has the highest ultimate tensile strength of 67.5 MPa, while the 100% rectilinear pattern shows 63.6 MPa. On the other hand, the 30% infill density samples show low strength, 32.4 MPa for concentric and 20.8 MPa for rectilinear infill patterns. Similar results can be derived from elastic modulus, yield strength, and stress at break results, while 30% concentric shows the maximum elongation rate of 0.016.

Abstract: Gyroid structures are one of the most common Triply Periodic Minimal Surfaces (TPMS) with remarkable mechanical properties, including energy absorption and stress distribution. In the current study, the compressive behavior of gyroid structures fabricated through Fused Deposition Modeling (FDM) was investigated. The deformation and failure mechanisms were predicted via extensive simulations using Finite Element Analysis tools. Experimental testing using Acrylonitrile Butadiene Styrene (ABS) specimens was performed on a Universal Testing Machine (UTM), and the results compared with computational data. To predict the compressive strength and optimize the structural parameters, an Artificial Neural Network (ANN) was trained. Results indicate a good match between the experimental and simulation findings, indicating immense potential for these gyroid structures in energy absorption.

Abstract: As freshwater availability has progressively decreased, this study presents a 3D-printed module housing system designed for solar-powered passive desalination and water production. To evaluate its performance, the module was tested in a controlled laboratory setting under one sun illumination. Under a salinity level of 3.5%, the design achieved an evaporation rate of 0.1458 kg/m²hr and a condensation rate of 0.0623 kg/m²hr, yielding a total of 20.13 g of desalinated water. The condensation efficiency was 42.7%, and the collected water had a salinity of 0.63%, highlighting opportunities for optimization in small-scale solar desalination. While these results indicate strong potential, further evaluation of the 3D-printed module housing will be conducted to assess its long-term durability, drinking water quality, and performance under outdoor conditions. With its modular design, efficient operation, and 3D-printed structure, this system holds promise as a scalable and sustainable solution for water-scarce communities worldwide.

Abstract: Shape memory polymers (SMPs) can recover from a programmed temporary shape to their original configuration when exposed to an external stimulus, most commonly heat, making them attractive materials for soft actuation in functional and biomedical devices. Among them, thermoplastic polyurethanes (TPUs) display reliable shape-memory behavior under various conditions. The emergence of biomedical-grade TPUs and their compatibility with additive manufacturing provides new opportunities for fabricating customized components with tunable actuation capabilities. In this study, biomedical TPU filaments were processed via fused deposition modeling (FDM) to produce block-shaped specimens of controlled size and weight. The samples were mechanically deformed into a C-shaped geometry at room temperature, fixed in fridge at the temperature of –20 °C, and subsequently tested under constrained recovery at room conditions, using a universal testing machine. The recovery load has been measured for a time of 30 min. The results show that TPU-based SMPs can develop substantial recovery forces during shape restoration. The shape memory behavior has been modeled by using a logistic function, which has been able to identify a characteristic time, the same for all the samples despite their printing conditions and architecture. These findings highlight the potential of FDM-processed biomedical TPUs for compact soft-actuation systems requiring high force output.

Abstract: The use of composite materials and specifically of Fiber Reinforced Polymers (FRP) is continuously increasing in structural applications due to their high strength-to-weight ratio. From an environmental perspective, composites still face relevant challenges due to impactful petroleum-based matrices and large amounts of waste generated during manufacturing processes. This study proposes the reuse of FRP machining waste as filler in Masked Stereolithography (M-SLA) 3D printing. Scraps from FRP laminates, obtained during drilling operations, were incorporated into a photocurable resin and used to print tensile and flexural specimens with increasing filler contents (0–5 wt%) and mechanical characterization tests were carried out. A cradle-to-grave Life Cycle Assessment (LCA) was performed to quantify the potential environmental benefits associated with the reduced use of virgin resin. Results show that the use of recycled FRP waste leads to a loss of tensile strength and stiffness (up to 61% and 21% respectively) but it also provides a reduction in Global Warming Potential (about 2% at 5 wt% filler). This demonstrates that the proposed strategy can improve the sustainability of 3D-printed components, especially for non-structural applications.

Abstract: Conventional manufacturing techniques for continuous carbon fiber-reinforced polymers (CFRP) rely on costly, geometry-specific molds, which substantially limit design flexibility. To overcome these constraints, this paper proposes a robot-based, multi-axis Fused Filament Fabrication (FFF) approach for the production of CFRP components of complex geometries. The setup enables advanced material placement so that support structures and internal cores can be avoided, thereby reducing process preparation effort, post-processing requirements, and overall manufacturing cost. As a case study, a tee pipe geometry is investigated. A dedicated slicing strategy is developed in which the main pipe and the branching section are fabricated sequentially. This approach requires precise cutting and controlled re-adhesion of the CFRP material, a critical capability for extending conventional neat-polymer FFF processes to the additive manufacturing of CFRP. Experimental validation demonstrated the feasibility of the process, highlighting the critical role of an innovative technique called nozzle ironing for surface preparation, as well as the challenges associated with fiber cutting mechanisms. While the final component achieved structural coherence, leakage testing revealed porosity at specific interface regions, suggesting directions for future hardware refinement and process optimization.

Abstract: 3D printing parameters such as printing temperatures and speeds play a vital role in the melt flow and printability of thermoplastic filaments in fused filament fabrication (FFF) technology. Inappropriate print settings mainly induce incomplete and poor printing quality due to melt flow instability. This research work focused on modeling the melt flow behavior of polylactic acid (PLA) at different printing temperatures and speeds using computer fluid dynamics (CFD) method. The shear stress and viscosity of PLA were investigated by a melt flow indexer (MFI) and rheometer in temperature ranges of 200 - 240 °C. A model of a capillary tube in MFI was set up with an initial condition of rheological properties from the experiment to simulate the hot melt extrusion relating to the melt flowability of PLA filaments. The high shear stress and low viscosity presented at the edge of filaments at every printing condition. Additionally, the shear stress and viscosity decreased linearly when the printing temperature increased, while the shear stress increased when the printing speed increased. The increase in shear stress caused high surface roughness of PLA specimens after printing. The findings can guide the optimization of the FFF 3D printing process to improve surface finish quality.

Abstract: Environmental worries have increased due to the sharp rise in single-use plastics in healthcare institutions, especially with relation to medical plastic waste. This study explores the viability of using low-cost, small-scale technology to recycle such trash into goods with added value. Samples of medical plastic, such as vials, syringes, and bottles of intravenous solution, were gathered at Al-Shamiya General Hospital, sanitized, and mechanically destroyed. Two processing units were created: a 3D printing filament extruder and a manual injection molding machine. While the injection molding machine generated molded components based on the applied mold design, the extruder successfully produced filaments suitable with fused deposition modeling. The technical feasibility of converting sterilized medical plastics into useful products for everyday use and healthcare was validated by experimental results. The results highlight the potential of decentralized recycling strategies to lessen the environmental impact of medical waste, promote circular economy principles, and decrease plastic pollution, so long as stringent safety and sterilizing measures are followed.