Shape optimization of a layer by layer mechanical constraint for additive manufacturing

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.

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Contactless temperature measurement in wire-based electron beam additive manufacturing Ti-6Al-4V

Welding in the World ◽

10.1007/s40194-021-01097-0 ◽

2021 ◽

Author(s):

F. Pixner ◽

R. Buzolin ◽

S. Schönfelder ◽

D. Theuermann ◽

F. Warchomicka ◽

...

Keyword(s):

Electron Beam ◽

Additive Manufacturing ◽

Thermal Imaging ◽

Temperature Profiles ◽

Layer By Layer ◽

Thermal Cycles ◽

Cooling Rates ◽

Geometric Boundary ◽

Microstructural Characterisation ◽

Local Misorientation

AbstractThe complex thermal cycles and temperature distributions observed in additive manufacturing (AM) are of particular interest as these define the microstructure and the associated properties of the part being built. Due to the intrinsic, layer-by-layer material stacking performed, contact methods to measure temperature are not suitable, and contactless methods need to be considered. Contactless infrared irradiation techniques were applied by carrying out thermal imaging and point measurement methods using pyrometers to determine the spatial and temporal temperature distribution in wire-based electron beam AM. Due to the vacuum, additional challenges such as element evaporation must be overcome and additional shielding measures were taken to avoid interference with the contactless techniques. The emissivities were calibrated by thermocouple readings and geometric boundary conditions. Thermal cycles and temperature profiles were recorded during deposition; the temperature gradients are described and the associated temperature transients are derived. In the temperature range of the α+β field, the cooling rates fall within the range of 180 to 350 °C/s, and the microstructural characterisation indicates an associated expected transformation of β→α'+α with corresponding cooling rates. Fine acicular α and α’ formed and local misorientation was observed within α as a result of the temperature gradient and the formation of the α’.

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A STRUCTURED APPROACH TO REDUCE DESIGN ITERATIONS IN ADDITIVE MANUFACTURING

Proceedings of the Design Society ◽

10.1017/pds.2021.24 ◽

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.

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Blade Segment with a 3D Lattice of Diamond Grits Fabricated via an Additive Manufacturing Process

Chinese Journal of Mechanical Engineering ◽

10.1186/s10033-020-00496-6 ◽

2020 ◽

Vol 33 (1) ◽

Author(s):

Bin Chen ◽

Peng Chen ◽

Yongjun Huang ◽

Xiangxi Xu ◽

Yibo Liu ◽

...

Keyword(s):

Additive Manufacturing ◽

Service Life ◽

Manufacturing Process ◽

Cutting Speed ◽

Inspection System ◽

Layer By Layer ◽

Filling Rate ◽

Pressure System ◽

Manufacturing Equipment ◽

Diamond Blade

Abstract Diamond tools with orderly arrangements of diamond grits have drawn considerable attention in the machining field owing to their outstanding advantages of high sharpness and long service life. This diamond super tool, as well as the manufacturing equipment, has been unavailable to Chinese enterprises for a long time due to patents. In this paper, a diamond blade segment with a 3D lattice of diamond grits was additively manufactured using a new type of cold pressing equipment (AME100). The equipment, designed with a rotary working platform and 16 molding stations, can be used to additively manufacture segments with diamond grits arranged in an orderly fashion, layer by layer; under this additive manufacturing process, at least 216000 pcs of diamond green segments with five orderly arranged grit layers can be produced per month. The microstructure of the segment was observed via SEM and the diamond blade fabricated using these segments was compared to other commercial cutting tools. The experimental results showed that the 3D lattice of diamond grits was formed in the green segment. The filling rate of diamond grits in the lattice could be guaranteed to be above 95%; this is much higher than the 90% filling rate of the automatic array system (ARIX). When used to cut stone, the cutting amount of the blade with segments made by AME100 is two times that of ordinary tools, with the same diamond concentration. When used to dry cut reinforced concrete, its cutting speed is 10% faster than that of ARIX. Under wet cutting conditions, its service life is twice that of ARIX. By applying the machine vision online inspection system and a special needle jig with a negative pressure system, this study developed a piece of additive manufacturing equipment for efficiently fabricating blade segments with a 3D lattice of diamond grits.

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A review of additive manufacturing applications in ophthalmology

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/09544119211028069 ◽

2021 ◽

pp. 095441192110280

Author(s):

Arivazhagan Pugalendhi ◽

Rajesh Ranganathan

Keyword(s):

Additive Manufacturing ◽

Treatment Planning ◽

Physical Object ◽

Layer By Layer ◽

Case Examples ◽

Manufacturing Method ◽

3D Cad ◽

Stl File ◽

Potential Applications ◽

Manufacturing Applications

Additive Manufacturing (AM) capabilities in terms of product customization, manufacture of complex shape, minimal time, and low volume production those are very well suited for medical implants and biological models. AM technology permits the fabrication of physical object based on the 3D CAD model through layer by layer manufacturing method. AM use Magnetic Resonance Image (MRI), Computed Tomography (CT), and 3D scanning images and these data are converted into surface tessellation language (STL) file for fabrication. The applications of AM in ophthalmology includes diagnosis and treatment planning, customized prosthesis, implants, surgical practice/simulation, pre-operative surgical planning, fabrication of assistive tools, surgical tools, and instruments. In this article, development of AM technology in ophthalmology and its potential applications is reviewed. The aim of this study is nurturing an awareness of the engineers and ophthalmologists to enhance the ophthalmic devices and instruments. Here some of the 3D printed case examples of functional prototype and concept prototypes are carried out to understand the capabilities of this technology. This research paper explores the possibility of AM technology that can be successfully executed in the ophthalmology field for developing innovative products. This novel technique is used toward improving the quality of treatment and surgical skills by customization and pre-operative treatment planning which are more promising factors.

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Evaluation of Parts Produced by a Novel Additive Manufacturing Process

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.315.63 ◽

2013 ◽

Vol 315 ◽

pp. 63-67 ◽

Cited By ~ 1

Author(s):

Muhammad Fahad ◽

Neil Hopkinson

Keyword(s):

Additive Manufacturing ◽

Rapid Prototyping ◽

Manufacturing Process ◽

High Speed ◽

Three Dimensional ◽

Coordinate Measuring Machine ◽

Layer By Layer ◽

Nylon 12 ◽

Measuring Machine ◽

End Use

Rapid prototyping refers to building three dimensional parts in a tool-less, layer by layer manner using the CAD geometry of the part. Additive Manufacturing (AM) is the name given to the application of rapid prototyping technologies to produce functional, end use items. Since AM is relatively new area of manufacturing processes, various processes are being developed and analyzed for their performance (mainly speed and accuracy). This paper deals with the design of a new benchmark part to analyze the flatness of parts produced on High Speed Sintering (HSS) which is a novel Additive Manufacturing process and is currently being developed at Loughborough University. The designed benchmark part comprised of various features such as cubes, holes, cylinders, spheres and cones on a flat base and the build material used for these parts was nylon 12 powder. Flatness and curvature of the base of these parts were measured using a coordinate measuring machine (CMM) and the results are discussed in relation to the operating parameters of the process.The result show changes in the flatness of part with the depth of part in the bed which is attributed to the thermal gradient within the build envelope during build.

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The role of robotics in additive manufacturing: review of the AM processes and introduction of an intelligent system

Industrial Robot the international journal of robotics research and application ◽

10.1108/ir-06-2021-0110 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

J. Norberto Pires ◽

Amin S. Azar ◽

Filipe Nogueira ◽

Carlos Ye Zhu ◽

Ricardo Branco ◽

...

Keyword(s):

Additive Manufacturing ◽

Computer Aided Design ◽

Intelligent System ◽

Material Selection ◽

High Strength Steels ◽

Industrial Applications ◽

Layer By Layer ◽

Content Type ◽

Functional Components

Purpose Additive manufacturing (AM) is a rapidly evolving manufacturing process, which refers to a set of technologies that add materials layer-by-layer to create functional components. AM technologies have received an enormous attention from both academia and industry, and they are being successfully used in various applications, such as rapid prototyping, tooling, direct manufacturing and repair, among others. AM does not necessarily imply building parts, as it also refers to innovation in materials, system and part designs, novel combination of properties and interplay between systems and materials. The most exciting features of AM are related to the development of radically new systems and materials that can be used in advanced products with the aim of reducing costs, manufacturing difficulties, weight, waste and energy consumption. It is essential to develop an advanced production system that assists the user through the process, from the computer-aided design model to functional components. The challenges faced in the research and development and operational phase of producing those parts include requiring the capacity to simulate and observe the building process and, more importantly, being able to introduce the production changes in a real-time fashion. This paper aims to review the role of robotics in various AM technologies to underline its importance, followed by an introduction of a novel and intelligent system for directed energy deposition (DED) technology. Design/methodology/approach AM presents intrinsic advantages when compared to the conventional processes. Nevertheless, its industrial integration remains as a challenge due to equipment and process complexities. DED technologies are among the most sophisticated concepts that have the potential of transforming the current material processing practices. Findings The objective of this paper is identifying the fundamental features of an intelligent DED platform, capable of handling the science and operational aspects of the advanced AM applications. Consequently, we introduce and discuss a novel robotic AM system, designed for processing metals and alloys such as aluminium alloys, high-strength steels, stainless steels, titanium alloys, magnesium alloys, nickel-based superalloys and other metallic alloys for various applications. A few demonstrators are presented and briefly discussed, to present the usefulness of the introduced system and underlying concept. The main design objective of the presented intelligent robotic AM system is to implement a design-and-produce strategy. This means that the system should allow the user to focus on the knowledge-based tasks, e.g. the tasks of designing the part, material selection, simulating the deposition process and anticipating the metallurgical properties of the final part, as the rest would be handled automatically. Research limitations/implications This paper reviews a few AM technologies, where robotics is a central part of the process, such as vat photopolymerization, material jetting, binder jetting, material extrusion, powder bed fusion, DED and sheet lamination. This paper aims to influence the development of robot-based AM systems for industrial applications such as part production, automotive, medical, aerospace and defence sectors. Originality/value The presented intelligent system is an original development that is designed and built by the co-authors J. Norberto Pires, Amin S. Azar and Trayana Tankova.

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Design and Analysis of Hybrid Fused Filament Fabrication Apparatus for Fabrication of Composites

Current Materials Science ◽

10.2174/2666145414666210412150641 ◽

2021 ◽

Vol 14 ◽

Author(s):

Aniket Yadav ◽

Piyush Chohan ◽

Ranvijay Kumar ◽

Jasgurpreet Singh Chohan ◽

Raman Kumar

Keyword(s):

Additive Manufacturing ◽

Composite Materials ◽

Design Process ◽

Low Cost ◽

Matrix Material ◽

Fabrication Process ◽

Layer By Layer ◽

Fused Filament Fabrication ◽

Composite Manufacturing ◽

Tool Paths

Background: Additive manufacturing is the most famous technology which requires materials or composites to be fabricated with layer by layer deposition strategy. Due to its lower cost, higher accuracy and less material wastage; this technology is used in almost every sector. But in many applications there is a need to alter the properties of a product in a certain direction with the help of some reinforcements. With the use of reinforcements, composite layers can be fabricated using additive manufacturing technique which will enhance the directional properties. A novel apparatus is designed to spray the reinforcement material into the printed structures in a very neat and precise manner. This spray nozzle is fully automated, which works according to tool-paths generated by slicing software. The alternate deposition of layers of reinforcement and build materials helped to fabricate customized composite products. Objective: The objective of present study is to design and analyze the working principle of novel technique which has been developed to fabricate composite materials using additive manufacturing. The apparatus is numerically controlled by computer according to CAD data which facilitates the deposition of alternate layers of reinforcement and matrix material. The major challenges during the design process and function of each component has been explored. Methods: The design process is initiated after comprehensive literature review performed to study previous composite manufacturing processes. The recent patents published by different patent offices of the world are studied in detail and analysis has been used to design a low cost composite fabrication apparatus. A liquid dispensing device comprises a storage tank attached with a pump and microprocessor. The microprocessor receives the signal from the computer as per tool paths generated by slicing software which decides the spray of reinforcements on polymer layers. The spraying apparatus moves in coordination with the primary nozzle of the Fused Filament Fabrication process. Results: The hybridization of Fused Filament Fabrication [process with metal spray process has been successfully performed. The apparatus facilitates the fabrication of low cost composite materials along with flexibility of complete customization of composite manufacturing process. The anisotropic behaviour of products can be easily controlled and managed during fabrication which can be used for different applications.

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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

wt Werkstattstechnik online ◽

10.37544/1436-4980-2017-06-31 ◽

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.

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Carbon Nanotube Reinforced Fused Deposition Modeling Using Microwave Irradiation

Volume 3: Joint MSEC-NAMRC Symposia ◽

10.1115/msec2016-8790 ◽

2016 ◽

Cited By ~ 2

Author(s):

Meng Zhang ◽

Xiaoxu Song ◽

Weston Grove ◽

Emmett Hull ◽

Z. J. Pei ◽

...

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Additive Manufacturing ◽

Microwave Irradiation ◽

Computer Aided Design ◽

Fused Deposition Modeling ◽

Layer By Layer ◽

Sem Images ◽

Fused Deposition ◽

Deposition Modeling

Additive manufacturing (AM) is a class of manufacturing processes where material is deposited in a layer-by-layer fashion to fabricate a three-dimensional part directly from a computer-aided design model. With a current market share of 44%, thermoplastic-based additive manufacturing such as fused deposition modeling (FDM) is a prevailing technology. A key challenge for AM parts (especially for parts made by FDM) in engineering applications is the weak inter-layer adhesion. The lack of bonding between filaments usually results in delamination and mechanical failure. To address this challenge, this study embedded carbon nanotubes into acrylonitrile butadiene styrene (ABS) thermoplastics via a filament extrusion process. The vigorous response of carbon nanotubes to microwave irradiation, leading to the release of a large amount of heat, is used to melt the ABS thermoplastic matrix adjacent to carbon nanotubes within a very short time period. This treatment is found to enhance the inter-layer adhesion without bulk heating to deform the 3D printed parts. Tensile and flexural tests were performed to evaluation the effects of microwave irradiation on mechanical properties of the specimens made by FDM. Scanning electron microscopic (SEM) images were taken to characterize the fracture surfaces of tensile test specimens. The actual carbon nanotube contents in the filaments were measured by conducting thermogravimetric analysis (TGA). The effects of microwave irradiation on the electrical resistivity of the filament were also reported.

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