Additive Manufacturing: Exploration of Porosity and Form Features Using Layer by Layer Deposition

2012 ◽  
Author(s):  
Devdas Shetty ◽  
Daniel Ly
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Performance ◽  
Raw Materials ◽  
High Strength ◽  
Complex Geometries ◽  
Layer By Layer ◽  
Monitoring And Control ◽  
Process Qualification ◽  
The Creation ◽  
Form Features

Aerospace companies use high-strength metal alloys like Inconel or Titanium which could be very difficult to fabricate using conventional methods. The current manufacturing techniques result in significant waste. Additive Manufacturing (AM), in its current state is not sufficiently understood, nor characterized such that conventional design practices and process qualification methodologies can be used. In addition, AM cannot be considered for the manufacture of aircraft components unless the process is stable and controlled. The mechanical properties of fabricated parts require to be characterized to demonstrate their invariability. The laser deposition using complex geometries is a challenge. In addition, the structural performances of AM parts have to be proved. Inherent in these requirements is the need to develop a process specification which requires the monitoring and control of key raw materials, consumables, and process parameters; the development of a fixed practice for each of the AM process. Several procedures are required in order to understand how additive manufacturing works using advanced and complex design models. The ability to adopt AM to the production of components is not only predicated on the ability of AM to be competitive with conventional manufacturing methods in terms of cost, but also on its ability to deliver parts with repeatable mechanical performance. The objective of this paper is to define and characterize the limitation of various complex geometries using additive manufacturing. The experimental research involved the creation of a number of specimens using direct metal laser sintering process, examination of their form features, documenting DMLS geometry limits for the form features and finally the creation of calibration models that can be used in aerospace design manuals.

scholarly journals Additive Manufacturing of Prostheses Using Forest-Based Composites

2020 ◽  
Vol 7 (3) ◽  
pp. 103
Author(s):  
Erik Stenvall ◽  
Göran Flodberg ◽  
Henrik Pettersson ◽  
Kennet Hellberg ◽  
Liselotte Hermansson ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Industrial Applications ◽  
Layer By Layer ◽  
Biobased Materials ◽  
Fused Deposition ◽  
Custom Made ◽  
Transtibial Prosthesis

A custom-made prosthetic product is unique for each patient. Fossil-based thermoplastics are the dominant raw materials in both prosthetic and industrial applications; there is a general demand for reducing their use and replacing them with renewable, biobased materials. A transtibial prosthesis sets strict demands on mechanical strength, durability, reliability, etc., which depend on the biocomposite used and also the additive manufacturing (AM) process. The aim of this project was to develop systematic solutions for prosthetic products and services by combining biocomposites using forestry-based derivatives with AM techniques. Composite materials made of polypropylene (PP) reinforced with microfibrillated cellulose (MFC) were developed. The MFC contents (20, 30 and 40 wt%) were uniformly dispersed in the polymer PP matrix, and the MFC addition significantly enhanced the mechanical performance of the materials. With 30 wt% MFC, the tensile strength and Young´s modulus was about twice that of the PP when injection molding was performed. The composite material was successfully applied with an AM process, i.e., fused deposition modeling (FDM), and a transtibial prosthesis was created based on the end-user’s data. A clinical trial of the prosthesis was conducted with successful outcomes in terms of wearing experience, appearance (color), and acceptance towards the materials and the technique. Given the layer-by-layer nature of AM processes, structural and process optimizations are needed to maximize the reinforcement effects of MFC to eliminate variations in the binding area between adjacent layers and to improve the adhesion between layers.

Basis für den industriellen 3D-Druck in Stahl/Basics for industrial 3D printing for steel - Contribution to additive manufacturing of complex products in multi-variant and functional skeleton construction

2017 ◽  
Vol 107 (06) ◽  
pp. 415-419
Author(s):  
M. Hillebrecht ◽  
V. Uhlenwinkel ◽  
A. von Hehl ◽  
H. Zapf ◽  
B. Schob
Keyword(s):  
Additive Manufacturing ◽  
Functional Integration ◽  
Complex Geometries ◽  
Layer By Layer ◽  
Laser Additive Manufacturing ◽  
Complex Products ◽  
Metal Parts ◽  
Laser Joining ◽  
Automation Technology ◽  
Selection Of

Mithilfe laserbasierter generativer Fertigungsverfahren (Laser Additive Manufacturing – LAM) ist es möglich, potentiell komplexe Bauteilgeometrien variantenreich herzustellen. Damit kann Gewicht eingespart werden und Funktionen sind integrierbar. In Kombination mit Automatisierungs- und innovativer Lasertechnik in der Schweiß- und Schneidapplikation lässt sich dieser Prozess wirtschaftlich nutzen. Durch pulverbettbasierte Lasergenerierverfahren können metallische Bauteile schichtweise aufgebaut werden, jedoch ist die Auswahl der Werkstoffe limitiert. Im Forschungsprojekt StaVari (Additive Fertigungsprozesse für komplexe Produkte in variantenreicher und hochfunktionaler Stahlbauweisen) vereinen sich die neuesten Erkenntnisse in Material-, Laser-, Füge- und Automatisierungstechnik, um modernen Anforderungen der Automobilbranche in der Massenfertigung sowie bei der Medizintechnik in der Kleinserie gerecht zu werden.   Laser Additive Manufacturing LAM has the potential to generate complex geometries. Through this weight reduction, functional integration and multi-variant production is possible. In combination with automation and innovative laser technology applicated in welding and cutting, this process can be used economically. With powderbed based laser additive manufacturing metal parts can be built up layer by layer. However selection of available metals is limited. In the project StaVari latest findings in material-, laser-, joining and automation technology are joint by qualified partners to meet modern automotive demands in mass production and medicine technology for small batch series.

scholarly journals On Residual Stress Development, Prevention, and Compensation in Metal Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 255 ◽  
Author(s):  
Kevin Carpenter ◽  
Ali Tabei
Keyword(s):  
Additive Manufacturing ◽  
Process Parameters ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Measurement Techniques ◽  
Complex Geometries ◽  
Quality Inspection ◽  
Metal Additive Manufacturing ◽  
Computational Costs ◽  
Metal Additive

One of the most appealing qualities of additive manufacturing (AM) is the ability to produce complex geometries faster than most traditional methods. The trade-off for this advantage is that AM parts are extremely vulnerable to residual stresses (RSs), which may lead to geometrical distortions and quality inspection failures. Additionally, tensile RSs negatively impact the fatigue life and other mechanical performance characteristics of the parts in service. Therefore, in order for AM to cross the borders of prototyping toward a viable manufacturing process, the major challenge of RS development must be addressed. Different AM technologies contain many unique features and parameters, which influence the temperature gradients in the part and lead to development of RSs. The stresses formed in AM parts are typically observed to be compressive in the center of the part and tensile on the top layers. To mitigate these stresses, process parameters must be optimized, which requires exhaustive and costly experimentations. Alternative to experiments, holistic computational frameworks which can capture much of the physics while balancing computational costs are introduced for rapid and inexpensive investigation into development and prevention of RSs in AM. In this review, the focus is on metal additive manufacturing, referred to simply as “AM”, and, after a brief introduction to various AM technologies and thermoelastic mechanics, prior works on sources of RSs in AM are discussed. Furthermore, the state-of-the-art knowledge on RS measurement techniques, the influence of AM process parameters, current modeling approaches, and distortion prevention approaches are reported.

Investigation of Parameter Spaces for Topology Optimization With Three-Dimensional Orientation Fields for Multi-Axis Additive Manufacturing

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Joseph R. Kubalak ◽  
Alfred L. Wicks ◽  
Christopher B. Williams
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Design Space ◽  
Mechanical Performance ◽  
Unit Length ◽  
Three Dimensions ◽  
Layer By Layer ◽  
Material Distribution ◽  
Orientation Fields ◽  
Material Orientation

Abstract The layer-by-layer deposition process used in material extrusion (ME) additive manufacturing results in inter- and intra-layer bonds that reduce the mechanical performance of printed parts. Multi-axis (MA) ME techniques have shown potential for mitigating this issue by enabling tailored deposition directions based on loading conditions in three dimensions (3D). Planning deposition paths leveraging this capability remains a challenge, as an intelligent method for assigning these directions does not exist. Existing literature has introduced topology optimization (TO) methods that assign material orientations to discrete regions of a part by simultaneously optimizing material distribution and orientation. These methods are insufficient for MA–ME, as the process offers additional freedom in varying material orientation that is not accounted for in the orientation parameterizations used in those methods. Additionally, optimizing orientation design spaces is challenging due to their non-convexity, and this issue is amplified with increased flexibility; the chosen orientation parameterization heavily impacts the algorithm’s performance. Therefore, the authors (i) present a TO method to simultaneously optimize material distribution and orientation with considerations for 3D material orientation variation and (ii) establish a suitable parameterization of the orientation design space. Three parameterizations are explored in this work: Euler angles, explicit quaternions, and natural quaternions. The parameterizations are compared using two benchmark minimum compliance problems, a 2.5D Messerschmitt–Bölkow–Blohm beam and a 3D Wheel, and a multi-loaded structure undergoing (i) pure tension and (ii) three-point bending. For the Wheel, the presented algorithm demonstrated a 38% improvement in compliance over an algorithm that only allowed planar orientation variation. Additionally, natural quaternions maintain the well-shaped design space of explicit quaternions without the need for unit length constraints, which lowers computational costs. Finally, the authors present a path toward integrating optimized geometries and material orientation fields resulting from the presented algorithm with MA–ME processes.

scholarly journals Processing of Aluminium-Silicon Alloy with Metal Carbide as Reinforcement through Powder-Based Additive Manufacturing: A Critical Study

Scanning ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-14
Author(s):  
R. Raj Mohan ◽  
R. Venkatraman ◽  
S. Raghuraman ◽  
P. Manoj Kumar ◽  
Moti Lal Rinawa ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Raw Materials ◽  
Cast Alloy ◽  
Critical Study ◽  
Layer By Layer ◽  
Aircraft Structure ◽  
Composite Fabrication ◽  
Art Research ◽  
Automotive Brake ◽  
Comprehensive Study

Powder-based additive manufacturing (PAM) is a potential fabrication approach in advancing state-of-the-art research to produce intricate components with high precision and accuracy in near-net form. In PAM, the raw materials are used in powder form, deposited on the surface layer by layer, and fused to produce the final product. PAM composite fabrication for biomedical implants, aircraft structure panels, and automotive brake rotary components is gaining popularity. In PAM composite fabrication, the aluminium cast alloy is widely preferred as a metal matrix for its unique properties, and different reinforcements are employed in the form of oxides, carbides, and nitrides. However, for enhancing the mechanical properties, the carbide form is predominantly considered. This comprehensive study focuses on contemporary research and reveals the effect of metal carbide’s (MCs) addition to the aluminium matrix processed through various PAM processes, challenges involved, and potential scopes to advance the research.

Direct Write Additive Manufacturing of High-Strength, Short Fiber Reinforced Sandwich Panels

2020 ◽  
Author(s):  
Nashat Nawafleh ◽  
Emrah Celik
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Mechanical Performance ◽  
Sandwich Panels ◽  
High Strength ◽  
Direct Write ◽  
Fiber Reinforced ◽  
Short Carbon Fiber ◽  
Carbon Fiber Reinforced ◽  
Short Carbon

Abstract Additive manufacturing (AM) is a novel technology which allows fabrication of complex geometries from digital representations without tooling. In addition, this technology results in low material waste, short lead times and cost reduction especially for the production of parts in low quantities. Current additive manufacturing processes developed for thermoplastic sandwich panels suffer from an unavoidable weak mechanical performance and low thermal resistance. To overcome these limitations, emphasis is paid in this study on direct write AM technology for the fabrication of short carbon fiber-reinforced sandwich panel composites. Sandwich panels using different infill densities with high strength (> 107 MPa), and high short carbon fiber volume (46%) were attained successfully. In parallel to the strength enhancement, these sandwich panels possessed reduced densities (0.72 g/cc3) due to their lightweight lattice core structures. The mechanical performance of the created sandwich panels was examined and compared to the unreinforced, base ink structures by performing compression tests. Successful fabrication and characterization of the additively manufactured thermoset-based carbon fiber reinforced, sandwich panels in this study can extend the range of applications for AM composites that require lightweight structures, high mechanical performance as well as the desired component complexity.

scholarly journals The Effect of Nanostructures in Aluminum Alloys Processed Using Additive Manufacturing on Microstructural Evolution and Mechanical Performance Behavior

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 524
Author(s):  
Rachel Boillat ◽  
Sriram Praneeth Isanaka ◽  
Frank Liou
Keyword(s):  
Additive Manufacturing ◽  
Aluminum Alloys ◽  
Manufacturing Industry ◽  
Mechanical Performance ◽  
Weight Ratio ◽  
High Strength ◽  
The Status ◽  
End Use ◽  
Am Processes ◽  
Performance Behavior

This paper reviews the status of nanoparticle technology as it relates to the additive manufacturing (AM) of aluminum-based alloys. A broad overview of common AM processes is given. Additive manufacturing is a promising field for the advancement of manufacturing due to its ability to yield near-net-shaped components that require minimal post-processing prior to end-use. AM also allows for the fabrication of prototypes as well as economical small batch production. Aluminum alloys processed via AM would be very beneficial to the manufacturing industry due to their high strength to weight ratio; however, many of the conventional alloy compositions have been shown to be incompatible with AM processing methods. As a result, many investigations have looked to methods to improve the processability of these alloys. This paper explores the use of nanostructures to enhance the processability of aluminum alloys. It is concluded that the addition of nanostructures is a promising route for modification of existing alloys and may be beneficial to other powder-based processes.

scholarly journals Theoretical and Experimental Investigation on the 3D Surface Roughness of Material Extrusion Additive Manufacturing Products

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 293
Author(s):  
Shijie Jiang ◽  
Ke Hu ◽  
Yang Zhan ◽  
Chunyu Zhao ◽  
Xiaopeng Li
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Surface Defects ◽  
Raw Materials ◽  
Fiber Direction ◽  
Layer By Layer ◽  
Forming Process ◽  
Material Extrusion ◽  
Proposed Model ◽  
Wide Range

Material extrusion (ME), one of the most widely used additive manufacturing technique, has the advantages of freedom of design, wide range of raw materials, strong ability to manufacture complex products, etc. However, ME products have obvious surface defects due to the layer-by-layer manufacturing characteristics. To reveal the generation mechanism, the three-dimensional surface roughness (3DSR) of ME products was investigated theoretically and experimentally. Based on the forming process of bonding neck, the 3DSR theoretical model in two different directions (vertical and parallel to the fiber direction) was established respectively. The preparation of ME samples was then completed and a series of experimental tests were performed to determine their surface roughness with the laser microscope. Through the comparison between theoretical and experimental results, the proposed model was validated. In addition, sensitivity analysis is implemented onto the proposed model, investigating how layer thickness, extrusion temperature, and extrusion width influence the samples’ surface roughness. This study provides theoretical basis and technical insight into improving the surface quality of ME products.

Additive Manufacturing of Kevlar Reinforced Epoxy Composites

2019 ◽  
Author(s):  
Nashat Nawafleh ◽  
Jordan Chabot ◽  
Mutabe Aljaghtham ◽  
Cagri Oztan ◽  
Edward Dauer ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Performance ◽  
Failure Strain ◽  
Flexural Modulus ◽  
Layer By Layer ◽  
Structural Components ◽  
Thermoset Composites ◽  
3D Objects ◽  
Layer Deposition ◽  
Subtractive Manufacturing

Abstract Additive manufacturing is defined as layer-by-layer deposition of materials on a surface to fabricate 3D objects with reduction in waste, unlike subtractive manufacturing processes. Short, flexible Kevlar fibers have been used in numerous studies to alter mechanical performance of structural components but never investigated within printed thermoset composites. This study investigates the effects of adding short Kevlar fibers on mechanical performance of epoxy thermoset composites and demonstrates that the addition of Kevlar by 5% in weight significantly improves flexure strength, flexural modulus, and failure strain by approximately 49%, 19%, and 38%, respectively. Hierarchical microstructures were imaged using scanning electron microscopy to observe the artefacts such as porosity, infill and material interdiffusion, which are inherent drawbacks of the 3D printing process.

Additive Manufacturing of Titanium Parts Using 3D Plasma Metal Deposition

2018 ◽  
Vol 941 ◽  
pp. 2137-2141 ◽  
Author(s):  
Kevin Hoefer ◽  
Peter Mayr
Keyword(s):  
Additive Manufacturing ◽  
Raw Materials ◽  
Deposition Process ◽  
Metal Deposition ◽  
Utilization Efficiency ◽  
Layer By Layer ◽  
Metallic Structures ◽  
Additional Advantage ◽  
Production Technologies ◽  
Material Utilization

Additive manufacturing of titanium components offers several advantages compared to conventional production technologies such as higher material utilization efficiency and increased geometric possibilities. In comparison to laser powder bed processes, arc-based additive manufacturing processes have the additional advantage of an almost unlimited assembly space, higher deposition rates and an improved utilisation factor of raw materials. Disadvantages of wire-based methods are the restricted availability of different types of wire consumables, the fact that the wire feed rate is directly coupled to the heat input and the lack of possibility to create multi-material structures in-situ.Within this work, the 3D Plasma Metal Deposition (3DPMD) method, based on a plasma powder deposition process is introduced. 3DPMD has some special advantages compared to the established plasma powder process and other additive processes. For example, up to four powders, which can differ in terms of material and powder fraction, can be mixed within one layer. This allows a targeted adaption of local properties (microstructure, mechanical properties, wear resistance, porosity, etc.) to the targeted load type and level. The tailored introduction of reinforcement particles, e.g. tungsten or titanium carbides, into the component is a simple example.The study aims to demonstrate the suitability of the 3DPMD for the production of titanium components in layer-by-layer design. Various demonstrators are prepared and analysed. The microstructures, the porosity and the hardness values of the different structures are analysed.In summary, 3DPMD offers the possibility to produce titanium structures with and without reinforcement particles. Using automated routines, it is possible to generate metallic structures directly from the CAD drawings using welding robots. Microstructures and properties are directly related to the process and, therefore, structure-process-property relationships are discussed within this work.

Sign in / Sign up

Export Citation Format

Share Document