scholarly journals A review on integration of lightweight gradient lattice structures in additive manufacturing parts

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402091695
Author(s):  
Asliah Seharing ◽  
Abdul Hadi Azman ◽  
Shahrum Abdullah
Keyword(s):  
Additive Manufacturing ◽  
Weight Ratio ◽  
Design Parameters ◽  
Layer By Layer ◽  
Lattice Structures ◽  
Unit Cells ◽  
Metallic Additive ◽  
Manufacturing Techniques ◽  
Future Work ◽  
Design Freedom

This review analyses the design, mechanical behaviors, manufacturability, and application of gradient lattice structures manufactured via metallic additive manufacturing technology. By varying the design parameters such as cell size, strut length, and strut diameter of the unit cells in lattice structures, a gradient property is obtained to achieve different levels of functionalities and optimize strength-to-weight ratio characteristics. Gradient lattice structures offer variable densification and porosities; and can combine more than one type of unit cells with different topologies which results in different performances in mechanical behavior layer-by-layer compared to non-gradient lattice structures. Additive manufacturing techniques are capable of manufacturing complex lightweight parts such as uniform and gradient lattice structures and hence offer design freedom for engineers. Despite these advantages, additive manufacturing has its own unique drawbacks in manufacturing lattice structures. The rules and strategies in overcoming the constraints are discussed and recommendations for future work were proposed.

scholarly journals Polymer-Based Additive Manufacturing: Process Optimisation for Low-Cost Industrial Robotics Manufacture

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2809
Author(s):  
Kartikeya Walia ◽  
Ahmed Khan ◽  
Philip Breedon
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Low Cost ◽  
Concept Development ◽  
Industrial Robots ◽  
Design Parameters ◽  
Initial Stage ◽  
Manufacturing Techniques ◽  
Robotics Design ◽  
Design Freedom

The robotics design process can be complex with potentially multiple design iterations. The use of 3D printing is ideal for rapid prototyping and has conventionally been utilised in concept development and for exploring different design parameters that are ultimately used to meet an intended application or routine. During the initial stage of a robot development, exploiting 3D printing can provide design freedom, customisation and sustainability and ultimately lead to direct cost benefits. Traditionally, robot specifications are selected on the basis of being able to deliver a specific task. However, a robot that can be specified by design parameters linked to a distinctive task can be developed quickly, inexpensively, and with little overall risk utilising a 3D printing process. Numerous factors are inevitably important for the design of industrial robots using polymer-based additive manufacturing. However, with an extensive range of new polymer-based additive manufacturing techniques and materials, these could provide significant benefits for future robotics design and development.

scholarly journals A STRUCTURED APPROACH TO REDUCE DESIGN ITERATIONS IN ADDITIVE MANUFACTURING

2021 ◽  
Vol 1 ◽  
pp. 231-240
Author(s):  
Laura Wirths ◽  
Matthias Bleckmann ◽  
Kristin Paetzold
Keyword(s):  
Additive Manufacturing ◽  
Spare Parts ◽  
Design Guidelines ◽  
Final Part ◽  
Layer By Layer ◽  
Powder Bed ◽  
Batch Sizes ◽  
Manufacturing Technologies ◽  
Structured Approach ◽  
Design Freedom

AbstractAdditive Manufacturing technologies are based on a layer-by-layer build-up. This offers the possibility to design complex geometries or to integrate functionalities in the part. Nevertheless, limitations given by the manufacturing process apply to the geometric design freedom. These limitations are often unknown due to a lack of knowledge of the cause-effect relationships of the process. Currently, this leads to many iterations until the final part fulfils its functionality. Particularly for small batch sizes, producing the part at the first attempt is very important. In this study, a structured approach to reduce the design iterations is presented. Therefore, the cause-effect relationships are systematically established and analysed in detail. Based on this knowledge, design guidelines can be derived. These guidelines consider process limitations and help to reduce the iterations for the final part production. In order to illustrate the approach, the spare parts production via laser powder bed fusion is used as an example.

Determination of Optimal Unit-Cell Size of Homogeneous Conformal Unit-Cell Lattice Structure Using Solid Shape Matching

2016 ◽  
Author(s):  
Mahmoud A. Alzahrani ◽  
Seung-Kyum Choi
Keyword(s):  
Cell Size ◽  
Solid Body ◽  
Strain Energy ◽  
Lattice Structure ◽  
Weight Ratio ◽  
Unit Cell ◽  
Optimal Size ◽  
Lattice Structures ◽  
Unit Cell Size ◽  
Unit Cells

With rapid developments and advances in additive manufacturing technology, lattice structures have gained considerable attention. Lattice structures are capable of providing parts with a high strength to weight ratio. Most work done to reduce computational complexity is concerned with determining the optimal size of each strut within the lattice unit-cells but not with the size of the unit-cell itself. The objective of this paper is to develop a method to determine the optimal unit-cell size for homogenous periodic and conformal lattice structures based on the strain energy of a given structure. The method utilizes solid body finite element analysis (FEA) of a solid counter-part with a similar shape as the desired lattice structure. The displacement vector of the lattice structure is then matched to the solid body FEA displacement results to predict the structure’s strain energy. This process significantly reduces the computational costs of determining the optimal size of the unit cell since it eliminates FEA on the actual lattice structure. Furthermore, the method can provide the measurement of relative performances from different types of unit-cells. The developed examples clearly demonstrate how we can determine the optimal size of the unit-cell based on the strain energy. Moreover, the computational cost efficacy is also clearly demonstrated through comparison with the FEA and the proposed method.

LATTICE STRUCTURE OPTIMIZATION WITH ORIENTATION-DEPENDENT MATERIAL PROPERTIES

2021 ◽  
pp. 1-33
Author(s):  
Conner Sharpe ◽  
Carolyn Seepersad
Keyword(s):  
Additive Manufacturing ◽  
Design Process ◽  
Material Properties ◽  
Computational Models ◽  
Lattice Structure ◽  
Lattice Structures ◽  
Performance Improvements ◽  
Structural Applications ◽  
Manufacturing Techniques ◽  
And Performance

Abstract Advances in additive manufacturing techniques have enabled the production of parts with complex internal geometries. However, the layer-based nature of additive processes often results in mechanical properties that vary based on the orientation of the feature relative to the build plane. Lattice structures have been a popular design application for additive manufacturing due to their potential uses in lightweight structural applications. Many recent works have explored the modeling, design, and fabrication challenges that arise in the multiscale setting of lattice structures. However, there remains a significant challenge in bridging the simplified computational models used in the design process and the more complex properties actually realized in fabrication. This work develops a design approach that captures orientation-dependent material properties that have been observed in metal AM processes while remaining suitable for use in an iterative design process. Exemplar problems are utilized to investigate the potential design changes and performance improvements that can be attained by taking the directional dependence of the manufacturing process into account in the design of lattice structures.

scholarly journals Taking into account thermal residual stresses in topology optimization of structures built by additive manufacturing

2018 ◽  
Vol 28 (12) ◽  
pp. 2313-2366 ◽  
Author(s):  
Grégoire Allaire ◽  
Lukas Jakabčin
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Residual Stresses ◽  
Heat Fluxes ◽  
Powder Layer ◽  
Layer By Layer ◽  
Thermal Deformations ◽  
Thermal Residual Stresses ◽  
Structural Design Optimization ◽  
Manufacturing Techniques

We introduce a model and several constraints for shape and topology optimization of structures, built by additive manufacturing techniques. The goal of these constraints is to take into account the thermal residual stresses or the thermal deformations, generated by processes like Selective Laser Melting, right from the beginning of the structural design optimization. In other words, the structure is optimized concurrently for its final use and for its behavior during the layer-by-layer production process. It is well known that metallic additive manufacturing generates very high temperatures and heat fluxes, which in turn yield thermal deformations that may prevent the coating of a new powder layer, or thermal residual stresses that may hinder the mechanical properties of the final design. Our proposed constraints are targeted to avoid these undesired effects. Shape derivatives are computed by an adjoint method and are incorporated into a level set numerical optimization algorithm. Several 2D and 3D numerical examples demonstrate the interest and effectiveness of our approach.

Lattice Structure Optimization With Orientation-Dependent Material Properties

2020 ◽  
Author(s):  
Conner Sharpe ◽  
Carolyn Conner Seepersad
Keyword(s):  
Additive Manufacturing ◽  
Design Process ◽  
Material Properties ◽  
Computational Models ◽  
Lattice Structure ◽  
Lattice Structures ◽  
Performance Improvements ◽  
Structural Applications ◽  
Manufacturing Techniques ◽  
And Performance

Abstract Advances in additive manufacturing techniques have enabled the production of parts with complex internal geometries. However, the layer-based nature of additive processes often results in mechanical properties that vary based on the orientation of the feature relative to the build plane. Lattice structures have been a popular design application for additive manufacturing due to their potential uses in lightweight structural applications. Many recent works have explored the modeling, design, and fabrication challenges that arise in the multiscale setting of lattice structures. However, there remains a significant challenge in bridging the simplified computational models used in the design process and the more complex properties actually realized in fabrication. This work develops a design approach that captures orientation-dependent material properties that have been observed in metal AM processes while remaining suitable for use in an iterative design process. Exemplar problems are utilized to investigate the potential design changes and performance improvements that can be attained by taking the directional dependence of the manufacturing process into account in the design of lattice structures.

scholarly journals Composite Reinforcement Architectures: A Review of Field-Assisted Additive Manufacturing for Polymers

2019 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Madhuparna Roy ◽  
Phong Tran ◽  
Tarik Dickens ◽  
Amanda Schrand
Keyword(s):  
Additive Manufacturing ◽  
External Field ◽  
Polymer Composites ◽  
Self Assembly ◽  
Weight Ratio ◽  
Basic Research ◽  
High Strength ◽  
Self Healing ◽  
Functional Capabilities ◽  
Manufacturing Techniques

The demand for additively manufactured polymer composites with increased specific properties and functional microstructure has drastically increased over the past decade. The ability to manufacture complex designs that can maximize strength while reducing weight in an automated fashion has made 3D-printed composites a popular research target in the field of engineering. However, a significant amount of understanding and basic research is still necessary to decode the fundamental process mechanisms of combining enhanced functionality and additively manufactured composites. In this review, external field-assisted additive manufacturing techniques for polymer composites are discussed with respect to (1) self-assembly into complex microstructures, (2) control of fiber orientation for improved interlayer mechanical properties, and (3) incorporation of multi-functionalities such as electrical conductivity, self-healing, sensing, and other functional capabilities. A comparison between reinforcement shapes and the type of external field used to achieve mechanical property improvements in printed composites is addressed. Research has shown the use of such materials in the production of parts exhibiting high strength-to-weight ratio for use in aerospace and automotive fields, sensors for monitoring stress and conducting electricity, and the production of flexible batteries.

Build Direction for Improved Process Plan in Multi-Material Additive Manufacturing

2014 ◽  
Author(s):  
Bashir Khoda
Keyword(s):  
Additive Manufacturing ◽  
Material Object ◽  
Layer By Layer ◽  
Multiple Features ◽  
Process Plan ◽  
Material Deposition ◽  
Heterogeneous Object ◽  
Build Time ◽  
Material Process ◽  
Manufacturing Techniques

Current additive manufacturing processes mostly accustomed with mono-material process plan algorithm to build object layer by layer. However, building a multi-material or heterogeneous object with an additive manufacturing system is fairly new but emerging concept. Unlike mono-material object, heterogeneous object contains multiple features or inhomogeneous architecture and can be decomposed into two dimensional heterogeneous layers with islands where each island represents associated feature’s properties. The material deposition path-plan in such multi-feature/multi-contour layers requires more resources and may affect the part integrity, quality, and build time. A novel framework is presented in this paper to determine the optimum build direction for heterogeneous object by differentiating the slice based on the resources requirement. Slices are bundled based on the heterogeneity and the effect of build directions are quantified considering the feature characteristics and manufacturing attributes. The proposed methodology is illustrated by examples with 50% or more homogeneous slices along the optimum build direction. The outcome would certainly benefit the process plan for multi-material additive manufacturing techniques.

scholarly journals Corrosion and Corrosion Protection of Additively Manufactured Aluminium Alloys—A Critical Review

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4804
Author(s):  
Reynier Revilla ◽  
Donovan Verkens ◽  
Tim Rubben ◽  
Iris De Graeve
Keyword(s):  
Additive Manufacturing ◽  
Corrosion Protection ◽  
Aluminium Alloys ◽  
Computer Aided Design ◽  
High Efficiency ◽  
Corrosion Behaviour ◽  
Weight Ratio ◽  
Future Research ◽  
Layer By Layer ◽  
Metal Parts

Metal additive manufacturing (MAM), also known as metal 3D printing, is a rapidly growing industry based on the fabrication of complex metal parts with improved functionalities. During MAM, metal parts are produced in a layer by layer fashion using 3D computer-aided design models. The advantages of using this technology include the reduction of materials waste, high efficiency for small production runs, near net shape manufacturing, ease of change or revision of versions of a product, support of lattice structures, and rapid prototyping. Numerous metals and alloys can nowadays be processed by additive manufacturing techniques. Among them, Al-based alloys are of great interest in the automotive and aeronautic industry due to their relatively high strength and stiffness to weight ratio, good wear and corrosion resistance, and recycling potential. The special conditions associated with the MAM processes are known to produce in these materials a fine microstructure with unique directional growth features far from equilibrium. This distinctive microstructure, together with other special features and microstructural defects originating from the additive manufacturing process, is known to greatly influence the corrosion behaviour of these materials. Several works have already been conducted in this direction. However, several issues concerning the corrosion and corrosion protection of these materials are still not well understood. This work reviews the main studies to date investigating the corrosion aspects of additively manufactured aluminium alloys. It also provides a summary and outlook of relevant directions to be explored in future research.

Defects and post-manufac- turing processes of additively manufactured steels: A Review (Part 2)

2020 ◽  
Vol 62 (8) ◽  
pp. 835-848
Author(s):  
Taban Emel ◽  
Olatunji Oladimeji Ojo
Keyword(s):  
Additive Manufacturing ◽  
Review Paper ◽  
Complex Geometry ◽  
Manufacturing Industries ◽  
Manufacturing Processes ◽  
Mechanical Responses ◽  
Engineering Steel ◽  
Manufacturing Techniques ◽  
Material Utilization ◽  
Design Freedom

Abstract Design freedom, complex geometry fabrication capability, minimal parts assembly and excellent material utilization attributes of additive manufacturing processes have provided a leverage ground for the development of functional engineering steel parts in the manufacturing industries. Despite the good attributes of additive manufacturing technology, there are still some local and inherent defects of as-built steel parts that can jeopardize the overall integrity of structural steel components. This review paper provides the associated defects of as-built steel and summarizes the post-manufacturing strategies being deployed to mitigate the severity of as-built steel defects. The microstructural and mechanical responses of some specific as-built steel under different fabrication conditions or additive manufacturing techniques are also summarized in this paper.

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