scholarly journals Interlayer bonding has bulk-material strength in extrusion additive manufacturing: New understanding of anisotropy

2020 ◽  
Vol 34 ◽  
pp. 101297 ◽  
Author(s):  
James Allum ◽  
Amirpasha Moetazedian ◽  
Andrew Gleadall ◽  
Vadim V. Silberschmidt
Keyword(s):  
Additive Manufacturing ◽  
Bulk Material ◽  
Material Strength ◽  
Interlayer Bonding

scholarly journals Size Effects in Finite Element Modelling of 3D Printed Bone Scaffolds Using Hydroxyapatite PEOT/PBT Composites

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1746
Author(s):  
Iñigo Calderon-Uriszar-Aldaca ◽  
Sergio Perez ◽  
Ravi Sinha ◽  
Maria Camara-Torres ◽  
Sara Villanueva ◽  
...  
Keyword(s):  
Finite Element ◽  
Additive Manufacturing ◽  
Tissue Regeneration ◽  
Finite Element Modelling ◽  
Bulk Material ◽  
Bone Tissue Regeneration ◽  
Patient Specific ◽  
Design Factor ◽  
Element Modelling ◽  
Uncertainty Sources

Additive manufacturing (AM) of scaffolds enables the fabrication of customized patient-specific implants for tissue regeneration. Scaffold customization does not involve only the macroscale shape of the final implant, but also their microscopic pore geometry and material properties, which are dependent on optimizable topology. A good match between the experimental data of AM scaffolds and the models is obtained when there is just a few millimetres at least in one direction. Here, we describe a methodology to perform finite element modelling on AM scaffolds for bone tissue regeneration with clinically relevant dimensions (i.e., volume > 1 cm3). The simulation used an equivalent cubic eight node finite elements mesh, and the materials properties were derived both empirically and numerically, from bulk material direct testing and simulated tests on scaffolds. The experimental validation was performed using poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) copolymers and 45 wt% nano hydroxyapatite fillers composites. By applying this methodology on three separate scaffold architectures with volumes larger than 1 cm3, the simulations overestimated the scaffold performance, resulting in 150–290% stiffer than average values obtained in the validation tests. The results mismatch highlighted the relevance of the lack of printing accuracy that is characteristic of the additive manufacturing process. Accordingly, a sensitivity analysis was performed on nine detected uncertainty sources, studying their influence. After the definition of acceptable execution tolerances and reliability levels, a design factor was defined to calibrate the methodology under expectable and conservative scenarios.

Tantalum as a Novel Biomaterial for Bone Implant: A Literature Review

2021 ◽  
Vol 52 ◽  
pp. 55-65
Author(s):  
Ivan Putrantyo ◽  
Nikhit Anilbhai ◽  
Revati Vanjani ◽  
Brigita De Vega
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Dental Implants ◽  
Bulk Material ◽  
High Melting Point ◽  
Design Modification ◽  
Bone Implant ◽  
Specific Strength ◽  
Metallic Implants ◽  
Tantalum Coatings

Titanium (Ti) has been used in metallic implants since the 1950s due to various biocompatible and mechanical properties. However, due to its high Young’s modulus, it has been modified over the years in order to produce a better biomaterial. Tantalum (Ta) has recently emerged as a new potential biomaterial for bone and dental implants. It has been reported to have better corrosion resistance and osteo-regenerative properties as compared to Ti alloys which are most widely used in the bone-implant industry. Currently, Tantalum cannot be widely used yet due to its limited availability, high melting point, and high-cost production. This review paper discusses various manufacturing methods of Tantalum alloys, including conventional and additive manufacturing and also discusses their drawbacks and shortcomings. Recent research includes surface modification of various metals using Tantalum coatings in order to combine bulk material properties of different materials and the porous surface properties of Tantalum. Design modification also plays a crucial role in controlling bulk properties. The porous design does provide a lower density, wider surface area, and more immense specific strength. In addition to improved mechanical properties, a porous design could also escalate the material's biological and permeability properties. With current advancement in additive manufacturing technology, difficulties in processing Tantalum could be resolved. Therefore, Tantalum should be considered as a serious candidate material for future bone and dental implants.

Effect of system compliance on weld power in ultrasonic additive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gowtham Venkatraman ◽  
Adam Hehr ◽  
Leon M. Headings ◽  
Marcelo J. Dapino
Keyword(s):  
Additive Manufacturing ◽  
Electrical Power ◽  
Three Dimensional ◽  
Power Input ◽  
Material Strength ◽  
Content Type ◽  
Ultrasonic Additive Manufacturing ◽  
Linear Elastic ◽  
Mechanical Compliance ◽  
The Relationship

Purpose Ultrasonic additive manufacturing (UAM) is a solid-state joining technology used for three-dimensional printing of metal foilstock. The electrical power input to the ultrasonic welder is a key driver of part quality in UAM, but under the same process parameters, it can vary widely for different build geometries and material combinations because of mechanical compliance in the system. This study aims to model the relationship between UAM weld power and system compliance considering the workpiece (geometry and materials) and the fixture on which the build is fabricated. Design/methodology/approach Linear elastic finite element modeling and experimental modal analysis are used to characterize the system’s mechanical compliance, and linear system dynamics theory is used to understand the relationship between weld power and compliance. In-situ measurements of the weld power are presented for various build stiffnesses to compare model predictions with experiments. Findings Weld power in UAM is found to be largely determined by the mechanical compliance of the build and insensitive to foil material strength. Originality/value This is the first research paper to develop a predictive model relating UAM weld power and the mechanical compliance of the build over a range of foil combinations. This model is used to develop a tool to determine the process settings required to achieve a consistent weld power in builds with different stiffnesses.

scholarly journals Increasing strength of FFF three-dimensional printed parts by influencing on temperature-related parameters of the process

2020 ◽  
Vol 26 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Vladimir E. Kuznetsov ◽  
Alexey N. Solonin ◽  
Azamat Tavitov ◽  
Oleg Urzhumtsev ◽  
Anna Vakulik
Keyword(s):  
Bulk Material ◽  
Three Dimensional ◽  
Fracture Load ◽  
Bending Test ◽  
Material Strength ◽  
Thermal Imager ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Temperature Conditions ◽  
Two Factors

Purpose This paper aims to investigate how the user-controlled parameters of the fused filament fabrication three-dimensional printing process define temperature conditions on the boundary between layers of the part being fabricated and how these conditions influence the structure and strength of the polylactic acid part. Design/methodology/approach Fracture load in a three-point bending test and calculated related stress were used as a measure. The samples were printed with the long side along the z-axis, thus, in the bend tests, the maximum stress occurred orthogonally to the layers. Temperature distribution on the sample surface during printing was monitored with a thermal imager. Sample mesostructure was analyzed using scanning electron microscopy. The influence of the extrusion temperature, the intensity of part cooling, the printing speed and the time between printing individual layers were considered. Findings It is shown that the optimization of the process parameters responsible for temperature conditions makes it possible to approximate the strength of the interlayer cohesion to the bulk material strength. Originality/value The novelty of the study consists in the generalization of the outcomes. All the parameters varied can be expressed through two factors, namely, the temperature of the previous layer and the extrusion efficiency, determining the ratio of the amount of extruded plastic to the calculated. A regression model was proposed that describes the effect of the two factors on the printed part strength. Along with interlayer bonding strength, these two factors determine the formation of the part mesostructure (the geometry of the boundaries between individual threads).

Topology optimization design of hydraulic valve blocks for additive manufacturing

2020 ◽  
Vol 234 (10) ◽  
pp. 1899-1912
Author(s):  
Guanlin Xie ◽  
Yongjia Dong ◽  
Jing Zhou ◽  
Zhongqi Sheng
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Hydraulic System ◽  
Optimization Design ◽  
Lightweight Design ◽  
Block Design ◽  
Reduction Rate ◽  
Material Strength ◽  
Hydraulic Valve ◽  
Valve Block

The hydraulic valve block is a core component of an integrated hydraulic system. In practical usage, it exhibits problems such as material waste, long manufacturing cycle, significant energy loss, and leakage. Based on the aforementioned existing problems, this study presents the design of the hydraulic system valve block based on the valve block design principle. The internal valve channel of the hydraulic valve block is optimized for additive manufacturing technology to avoid auxiliary drilling, solve the problem of potential liquid leakage, and shorten the manufacturing cycle. Thus, it is more suitable for the production of customized complex hydraulic valve blocks. The multiobjective topology optimization method is applied to the lightweight design of the hydraulic valve block to save resources and decrease energy consumption. The results indicate that when compared with the original model, the minimum reduction rate of pressure loss in each oil circuit orifice after optimization of the hydraulic valve block corresponds to 32.02%, the maximum corresponds to 71.38%; the maximum stress of the final design corresponds to 542.9 MPa, which satisfies the material strength requirement; and the mass is decreased by 68.9%. Thus, the lightweight design of the hydraulic valve block is realized.

Steering column support topology optimization including lattice structure for metal additive manufacturing

2020 ◽  
pp. 095440622094712
Author(s):  
S Mantovani ◽  
GA Campo ◽  
M Giacalone
Keyword(s):  
Additive Manufacturing ◽  
Bulk Material ◽  
Optimization Methods ◽  
Functionally Graded ◽  
Lattice Structures ◽  
Advantages And Disadvantages ◽  
Thin Walled Structures ◽  
Wide Range ◽  
Thin Walled ◽  
Graded Lattice

Structural engineering in the automotive industry has moved towards weight reduction and passive safety whilst maintaining a good structural performance. The development of Additive Manufacturing (AM) technologies has boosted design freedom, leading to a wide range of geometries and integrating functionally-graded lattice structures. This paper presents three AM-oriented numerical optimization methods, aimed at optimizing components made of: i) bulk material, ii) a combination of bulk material and graded lattice structures; iii) an integration of solid, lattice and thin-walled structures. The optimization methods were validated by considering the steering column support of a mid-rear engine sports car, involving complex loading conditions and shape. The results of the three methods are compared, and the advantages and disadvantages of the solutions are discussed. The integration between solid, lattice thin-walled structures produced the best results, with a mass reduction of 49.7% with respect to the existing component.

A Multi-Scale Topology Optimization Approach for Optimal Macro-Layout and Local Grading of TPMS-Based Lattices

2021 ◽  
Author(s):  
Niclas Strömberg
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Local Density ◽  
Bulk Material ◽  
Transversely Isotropic ◽  
Benchmark Problems ◽  
Optimization Approach ◽  
Lattice Structures ◽  
Efficient Design ◽  
Multi Scale

Abstract The use of lattice structures in design for additive manufacturing has quickly emerged as a popular and efficient design alternative for creating innovative multifunctional lightweight solutions. In particular, the family of triply periodic minimal surfaces (TPMS) studied in detail by Schoen for generating frame-or shell-based lattice structures seems extra promising. In this paper a multi-scale topology optimization approach for optimal macro-layout and local grading of TPMS-based lattice structures is presented. The approach is formulated using two different density fields, one for identifying the macro-layout and another one for setting the local grading of the TPMS-based lattice. The macro density variable is governed by the standard SIMP formulation, but the local one defines the orthotropic elasticity of the element following material interpolation laws derived by numerical homogenization. Such laws are derived for frame- and shell-based Gyroid, G-prime and Schwarz-D lattices using transversely isotropic elasticity for the bulk material. A nice feature of the approach is that the lower and upper additive manufacturing limits on the local density of the TMPS-based lattices are included properly. The performance of the approach is excellent, and this is demonstrated by solving several three-dimensional benchmark problems, e.g., the optimal macro-layout and local grading of Schwarz-D lattice for the established GE-bracket is identified using the presented approach.

scholarly journals Automated Assembly of Electronic Digital Materials

2016 ◽  
Author(s):  
Will Langford ◽  
Amanda Ghassaei ◽  
Neil Gershenfeld
Keyword(s):  
Additive Manufacturing ◽  
Bulk Material ◽  
Building Blocks ◽  
Material Structure ◽  
Automated Assembly ◽  
Design And Implementation ◽  
Positioning Errors ◽  
Assembly Sequences ◽  
Digital Material ◽  
Cad Cam

Interest in additive manufacturing has recently been spurred by the promise of multi-material printing and the ability to embed functionality and intelligence into objects. Here, we present an alternative to additive manufacturing, introducing an end-to-end workflow in which discrete building blocks are reversibly joined to produce assemblies called digital materials. We describe the design of the bulk-material building blocks and the devices that are assembled from them. Further, we detail the design and implementation of an automated assembler, which takes advantage of the digital material structure to restore positioning errors within a large tolerance. To generate assembly sequences, we use a novel CAD/CAM workflow for designing, simulating, and assembling digital materials. Finally, we evaluate the structures assembled using this process, showing that the joints perform well under varying conditions and that the assembled structures are functionally precise.

Mechanical Property Testing and Analysis of 3D Printing Objects

2016 ◽  
Author(s):  
Xiaobin Le ◽  
Rami Akouri ◽  
Anthony Latassa ◽  
Brett Passemato ◽  
Ryan Wales
Keyword(s):  
Mechanical Property ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Tensile Test ◽  
Acrylonitrile Butadiene Styrene ◽  
Material Strength ◽  
Original Material ◽  
Tensile Test Specimen ◽  
3D Objects ◽  
Nylon 12

3D printing known as additive manufacturing has been widely used in academics and industries to make various 3D objects for various applications. The strength of the 3D printing parts is different from its original material strength due to this additive manufacturing technique. The 3D printing parts should be treated as anisotropic materials. However, the information of mechanical property such as the ultimate strength of 3D printing parts is very limited. There is little information about the mechanical property of 3D printing parts at different print angles. This research was focused on exploring the mechanical properties of 3D printing objects. The tensile test specimen of two different materials: acrylonitrile butadiene styrene-electrostatic dissipative (ABS-ESD) and Nylon 12 were printed at the 5 different print angles through the Fortus 450mc 3D printer. Tensile test results, data analysis, detailed discussion and the empirical formula of the tensile strength of 3D printing objects vs different print angles will be presented.

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