scholarly journals Mechanical behavior of beams with variable stiffness obtained by 3D printing

2021 ◽  
Vol 343 ◽  
pp. 08014
Author(s):  
Laszlo Racz ◽  
Mircea Cristian Dudescu
Keyword(s):  
3D Printing ◽  
Mechanical Behavior ◽  
Cross Section ◽  
Process Parameters ◽  
Fused Deposition Modeling ◽  
Cost Effective ◽  
Variable Stiffness ◽  
Constant Cross Section ◽  
Printing Process ◽  
Fused Deposition

Additive manufacturing or 3D printing gained a widespread popularity in recent years due to the ability of the method to manufacture components with high geometrical complexity. The most cost-effective process to manufacture plastic parts using 3D printing is the fused deposition modeling (FDM) method. Process parameters as the infill rates but also the printed pattern of different layers and their orientation have a significant influence on the mechanical properties of specimens fabricated by FDM. Controlling the process parameters is possible to generate materials with variable mechanical proprieties. The paper presents the analysis of a beam with constant cross-section but variable stiffness. Variable stiffness is achieved by changes in different cross-sections of the beam of the infill rates of the printing process. The mechanical behavior consisting of force-displacements curves is analyzed by three-point bending tests of variable stiffness samples and comparison with similar beams having constant infill rate. The results consist of E-modulus variation, maximum force and deflection curve. Analytical calculations and finite element analyses are employed to predict the mechanical behavior of the specimens printed with variable infill rate. The obtained results proved the concept of equal stress-beam with constant cross-section obtained by 3D printing process parameters variation.

scholarly journals Investigation of Compressive Behavior of Pre-folded Thin-walled Column Fabricated by 3D Printing

2021 ◽  
Vol 6 (3) ◽  
pp. 543-560
Author(s):  
Farid Triawan ◽  
Elin Rachmawati ◽  
Bentang Arief Budiman ◽  
Djati Wibowo Djamari ◽  
Andy Saputro ◽  
...  
Keyword(s):  
3D Printing ◽  
Mechanical Behavior ◽  
Cross Section ◽  
Fused Deposition Modeling ◽  
Compressive Loading ◽  
Local Deformation ◽  
Element Analysis ◽  
Prosthetic Devices ◽  
Fused Deposition ◽  
Thin Walled

This paper reveals the mechanical behavior of thin-walled columns with pre-folded patterns subjected to compressive loading. The column specimens (Polylactic Acid) are fabricated using Fused Deposition Modeling 3D printer and subjected to quasi-static compressive loading to investigate their mechanical behavior (by modifying the specimens' cross-section patterns and folding angles). The column specimens are simulated by finite element analysis to understand how the stress distribution and local deformation affecting the stiffness, strength, and overall deformation. The experiments showed that introducing the pre-folded pattern in a thin-walled column with different cross-sections can dramatically lower its structural stiffness (85%) and compressive strength (69%), but increase its deformability (115%), which is good agreement with numerical simulation. The variation of cross-section patterns and pre-folding angle could effectively modify the compressive mechanical behavior. Moreover, the results demonstrate how the FDM 3D Printing method can be used in fabricating a thin-walled column with irregular shapes and then to modify its deformability. This finding can be useful for designing any complex structures requiring specific stiffness and deformation such as suspension devices, prosthetic devices in biomechanics, and robotic structures.

scholarly journals Enhancing Structural Performance of Short Fiber Reinforced Objects through Customized Tool-Path

2020 ◽  
Vol 10 (22) ◽  
pp. 8168
Author(s):  
Jaeyoon Kim ◽  
Bruce S. Kang
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Behavior ◽  
Case Studies ◽  
Fused Deposition Modeling ◽  
Tool Path ◽  
Spur Gear ◽  
Fiber Reinforced ◽  
Printing Process ◽  
Fused Deposition

Fused deposition modeling (FDM) is one of the most common additive manufacturing (AM) technologies for thermoplastic materials. With the development of carbon fiber-reinforced polymer (CFRP) filament for FDM, AM parts with improved strength and functionality can be realized. CFRP is anisotropic material and its mechanical properties have been well studied, however, AM printing strategy for CFRP parts has not been developed. This paper proposes a systematic optimization of the FDM 3D printing process for CFRP. Starting with standard coupon specimen tests to obtain mechanical properties of CFRP, finite element analyses (FEA) were conducted to find principal directions of the AM part and utilized to determine fiber orientations. A specific tool-path algorithm has been developed to distribute fibers with the desired orientations. To predict/assess the mechanical behavior of the AM part, the 3D printing process was simulated to obtain the anisotropic mechanical behavior induced by the customized tool-path printing. Bolt hole plate and spur gear were selected as case studies. FE simulations and associated experiments were conducted to assess their performance. CFRP parts printed by the optimized tool-path shows about 8% higher stiffness than those printed at regular infill patterns. In summary, assisted by FEA, a customized 3D printing tool-path for CFRP has been developed with case studies to verify the proposed AM design optimization methodology for FDM.

Rapid Manufacture of Novel Variable Impedance Robots

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Alexander Enoch ◽  
Sethu Vijayakumar
Keyword(s):  
3D Printing ◽  
Degrees Of Freedom ◽  
Fused Deposition Modeling ◽  
Complex Dynamics ◽  
Cost Effective ◽  
Variable Stiffness ◽  
Fused Deposition ◽  
Impedance Modulation ◽  
Variable Damping ◽  
Rapid Manufacture

Variable stiffness and variable damping can play an important role in robot movement, particularly for legged robots such as bipedal walkers. Variable impedance also introduces new control problems, since there are more degrees of freedom to control, and the resulting robot has more complex dynamics. In this paper, we introduce novel design and fabrication methodologies that are capable of producing cost effective hardware prototypes suitable for investigating the efficacy of impedance modulation. We present two variable impedance bipedal platforms produced using a combination of waterjet cutting and 3D printing, and a novel fused deposition modeling (FDM) 3D printing based method for producing hybrid plastic/metal parts. We evaluate walking trajectories at different speeds and stiffness levels.

Hochproduktiver fertigungsangepasster 3D-Druck/Productive and manufacturing adjusted 3D printing

2017 ◽  
Vol 107 (07-08) ◽  
pp. 520-523
Author(s):  
J. Prof. Bliedtner ◽  
M. Schilling
Keyword(s):  
3D Printing ◽  
Research And Development ◽  
Fused Deposition Modeling ◽  
Dynamic Properties ◽  
Development Project ◽  
Efficient Production ◽  
Large Format ◽  
Printing Process ◽  
Fused Deposition ◽  
Deposition Modeling

Das FDM (Fused Deposition Modeling)-Verfahren ist aufgrund der Vielzahl von industriellen und privaten Anwendungen gegenwärtig das erfolgreichste 3D-Druck-Verfahren. Ziel des Forschungs- und Entwicklungsprojektes „HP3D“ ist die effiziente Herstellung von großformatigen Bauteilen in einem echten 3D-Verfahren aus frei wählbaren thermoplastischen Kunststoffen. An die Umsetzung des Projekts wurde sehr komplex herangegangen, um zu garantieren, dass die mechanischen und dynamischen Eigenschaften der aufgebauten Teile den konzipierten Eigenschaften entsprechen.   The FDM process is currently the most successful 3D printing process due to the multitude of industrial and private applications. The aim of the research and development project HP3D is the efficient production of large-format components in a real 3D process made of freely selectable thermoplastics. The implementation of the project has been very complex in order to ensure that the mechanical and dynamic properties of the assembled parts correspond to the designed properties.

A Heuristic Scaling Strategy for Multi-Robot Cooperative Three-Dimensional Printing

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Laxmi Poudel ◽  
Chandler Blair ◽  
Jace McPherson ◽  
Zhenghui Sha ◽  
Wenchao Zhou
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Evaluation Framework ◽  
Geometric Constraints ◽  
Mathematical Representation ◽  
Printing Process ◽  
Fused Deposition ◽  
3D Printers ◽  
Printing Time

Abstract While three-dimensional (3D) printing has been making significant strides over the past decades, it still trails behind mainstream manufacturing due to its lack of scalability in both print size and print speed. Cooperative 3D printing (C3DP) is an emerging technology that holds the promise to mitigate both of these issues by having a swarm of printhead-carrying mobile robots working together to finish a single print job cooperatively. In our previous work, we have developed a chunk-based printing strategy to enable the cooperative 3D printing with two fused deposition modeling (FDM) mobile 3D printers, which allows each of them to print one chunk at a time without interfering with the other and the printed part. In this paper, we present a novel method in discretizing the continuous 3D printing process, where the desired part is discretized into chunks, resulting in multi-stage 3D printing process. In addition, the key contribution of this study is the first working scaling strategy for cooperative 3D printing based on simple heuristics, called scalable parallel arrays of robots for 3DP (SPAR3), which enables many mobile 3D printers to work together to reduce the total printing time for large prints. In order to evaluate the performance of the printing strategy, a framework is developed based on directed dependency tree (DDT), which provides a mathematical and graphical description of dependency relationships and sequence of printing tasks. The graph-based framework can be used to estimate the total print time for a given print strategy. Along with the time evaluation metric, the developed framework provides us with a mathematical representation of geometric constraints that are temporospatially dynamic and need to be satisfied in order to achieve collision-free printing for any C3DP strategy. The DDT-based evaluation framework is then used to evaluate the proposed SPAR3 strategy. The results validate the SPAR3 as a collision-free strategy that can significantly shorten the printing time (about 11 times faster with 16 robots for the demonstrated examples) in comparison with the traditional 3D printing with single printhead.

Morphological evaluation of microcellular foamed composites developed through gas batch foaming integrating Fused Deposition Modeling (FDM) 3D printing technique

2021 ◽  
pp. 026248932110409
Author(s):  
G Radhakrishna ◽  
Rupesh Dugad ◽  
Abhishek Gandhi
Keyword(s):  
3D Printing ◽  
Process Parameters ◽  
Fused Deposition Modeling ◽  
Saturation Pressure ◽  
Average Cell ◽  
Fused Deposition ◽  
Printing Technique ◽  
Deposition Modeling ◽  
3D Printing Technique ◽  
Batch Foaming

In this article, the development of microcellular structure foams has developed by integrating the two successful and existing technologies, namely CO2 gas batch foaming and Fused Deposition Modeling (FDM) 3D printing technique. It is a novel approach to manufacture complex design porous products for customized applications. The eventual cell morphologies of the extruded 3D printing filament depends on the process parameters pertaining to both microcellular foaming and 3D printing processes. Further, morphological study has been conducted to evaluate the cell morphologies of the 3D printing filament developed through customized FDM setup. During this process, the significance of various process parameters including saturation pressure, saturation time, desorption time, feed rate and extrusion temperature were thoroughly studied. To pursue this study base material used was acrylonitrile butadiene styrene (ABS). The 3D printed filaments consisted of cells with an average cell size in the range of 2.3–276 µm and the average cell density in the range of 4.7 × 104 to 4.3 × 109 cells/cm3. Finally, it has found that by controlling the process parameters different cell morphologies can be developed as per the end application.

scholarly journals Mesh-type 3D Printing of Human Organs and Tumors: Fast, Cost-Effective, and Personalized Anatomic Modeling

2020 ◽  
Author(s):  
Jungirl Seok ◽  
Sungmin Yoon ◽  
Chang Hwan Ryu ◽  
Junsun Ryu ◽  
Seok-ki Kim ◽  
...  
Keyword(s):  
3D Printing ◽  
3D Modeling ◽  
Fused Deposition Modeling ◽  
Cost Effective ◽  
Tumor Location ◽  
Surgical Specimen ◽  
Personalized Care ◽  
Fused Deposition ◽  
Mesh Work ◽  
Deposition Modeling

OBJECTIVE: Although 3D-printed anatomic models are not new to medicine, the high costs and lengthy production times entailed have limited their application. Our goal was developing a new and less costly 3D modeling method to depict organ-tumor relations at faster printing speeds. METHODS: We have devised a method of 3D modeling using DICOM images. Coordinates are extracted at a specified interval, connecting them to create mesh-work replicas. Adjacent constructs are depicted by density variations, showing anatomic targets (ie, tumors) in contrasting color. RESULTS: An array of organ solid-tumor models were printed via Fused Deposition Modeling 3D printer at significantly less cost ($0.05/cm3) and time expenditure (1.73 min/cm3; both, p<.001). Printed models helped promote visual appreciation of organ-tumor anatomy and adjacent tissues. Our mesh-work 3D thyroidal prototype reproduced glangular size/contour and tumor location, readily approximating the surgical specimen. CONCLUSIONS: This newly devised mesh-type 3D printing method may facilitate anatomic modeling for personalized care and improve patient awareness during informed surgical consent.

scholarly journals Dimensional Stability of 3D Printed Objects Made from Plastic Waste Using FDM: Potential Construction Applications

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 516
Author(s):  
Essam Zaneldin ◽  
Waleed Ahmed ◽  
Aya Mansour ◽  
Amged El Hassan
Keyword(s):  
3D Printing ◽  
Construction Projects ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Cost Effective ◽  
Plastic Waste ◽  
Fused Deposition ◽  
Feasible Option ◽  
3D Printers ◽  
3D Printed

Construction projects are often challenged by tight budgets and limited time and resources. Contractors are, therefore, looking for ways to become competitive by improving efficiency and using cost-effective materials. Using three-dimensional (3D) printing for shaping materials to produce cost-effective construction elements is becoming a feasible option to make contractors more competitive locally and globally. The process capabilities for 3D printers and related devices have been tightened in recent years with the booming of 3D printing industries and applications. Contractors are attempting to improve production skills to satisfy firm specifications and standards, while attempting to have costs within competitive ranges. The aim of this research is to investigate and test the production process capability (Cp) of 3D printers using fused deposition modeling (FDM) to manufacture 3D printed parts made from plastic waste for use in the construction of buildings with different infill structures and internal designs to reduce cost. This was accomplished by calculating the actual requirement capabilities of the 3D printers under consideration. The production capabilities and requirements of FDM printers are first examined to develop instructions and assumptions to assist in deciphering the characteristics of the 3D printers that will be used. Possible applications in construction are then presented. As an essential outcome of this study, it was noticed that the 3D printed parts made from plastic waste using FDM printers are less expensive than using traditional lightweight non-load bearing concrete hollow masonry blocks, hourdi slab hollow bocks, and concrete face bricks.

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