Development of novel additive manufacturing technology: an investigation of a selective composite formation process

2016 ◽  
Vol 22 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Marlon Wesley Machado Cunico ◽  
Jonas de Carvalho
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Formation Process ◽  
Process Window ◽  
Preliminary Evaluation ◽  
Beam Diameter ◽  
Light Power ◽  
Content Type ◽  
Straight Line ◽  
Composite Formation

Purpose – The purpose of this study is to present a novel additive manufacturing (AM) technology which is based on selective formation of cellulose-acrylate composite. Besides proposing a process that combines the benefits of fibres and photopolymers, this paper reports the development of material, characterisation of a straight line composite formation, adherence between layers and functional feasibility of the proposed concept. Design/methodology/approach – For the preliminary evaluation of the proposed process, a composite material based on cellulose-photopolymer was developed, while a multi-objective optimisation study indicated the formulation which results in the maximum values of layer adherence, tensile strength of composite and the effect of the water on the mechanical strength of material. For the characterisation of the process, three main subjects were analysed: the characterisation of straight line composite formation, the effect of composite formation process on previous layers and the functional feasibility of technology. Findings – In the material development, the tensile strength of dry composite was identified between 20 and 30 MPa, while the tensile strength of wet composite was between 5 and 12 MPa. It is important to note that the dry and wet cellulose presented tensile strength, respectively, equal to 15 and 1 MPa, indicating the possibility of residual material removal only with the use of water or other soft solvent. The values of adherence between layers (peeling test) were found to be between 0.12 and 0.15 kgf, and the photopolymer formulation which resulted in the maximum adherence has monomer/oligomer ratio equal to 1.5 and 2 per cent wt of photoinitiator percentual. As result of the optimisation study, the material formulation was compounded by monomer – 10 ml, oligomer – 4.5 ml and photoinitiator – 2 per cent, being found suitable to characterise and evaluate the proposed process. The study of composite formation along a straight line showed values of line width between 1,400 and 3,500 μm in accordance with light power, laser velocity and laser beam diameter. On the other hand, the number of previous layers affected by the composite formation varied from 0 to 4, indicating a potential process limit. In the functional feasibility study, a feasible process window which resulted in the maximum dimensional deviation equal to 0.5 mm was identified. In addition, the mean mechanical tensile strength was found to be around 30 MPa for longitudinal laser trajectory (90°) and 15 MPa for transversal laser trajectory (0°), highlighting the anisotropic behaviour of final parts according to the manufacturing strategy. Originality/value – This paper proposed a novel AM technology and also described studies related to the characterisation of this concept. This work might also be useful to the development of other AM processes and applications.

Additive manufacturing using fine wire-based laser metal deposition

2019 ◽  
Vol 26 (3) ◽  
pp. 473-483
Author(s):  
Muhammad Omar Shaikh ◽  
Ching-Chia Chen ◽  
Hua-Cheng Chiang ◽  
Ji-Rong Chen ◽  
Yi-Chin Chou ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
High Precision ◽  
Surface Finish ◽  
Dimensional Accuracy ◽  
Laser Metal Deposition ◽  
Cross Sectional ◽  
Content Type ◽  
Fine Wire

Purpose Using wire as feedstock has several advantages for additive manufacturing (AM) of metal components, which include high deposition rates, efficient material use and low material costs. While the feasibility of wire-feed AM has been demonstrated, the accuracy and surface finish of the produced parts is generally lower than those obtained using powder-bed/-feed AM. The purpose of this study was to develop and investigate the feasibility of a fine wire-based laser metal deposition (FW-LMD) process for producing high-precision metal components with improved resolution, dimensional accuracy and surface finish. Design/methodology/approach The proposed FW-LMD AM process uses a fine stainless steel wire with a diameter of 100 µm as the additive material and a pulsed Nd:YAG laser as the heat source. The pulsed laser beam generates a melt pool on the substrate into which the fine wire is fed, and upon moving the X–Y stage, a single-pass weld bead is created during solidification that can be laterally and vertically stacked to create a 3D metal component. Process parameters including laser power, pulse duration and stage speed were optimized for the single-pass weld bead. The effect of lateral overlap was studied to ensure low surface roughness of the first layer onto which subsequent layers can be deposited. Multi-layer deposition was also performed and the resulting cross-sectional morphology, microhardness, phase formation, grain growth and tensile strength have been investigated. Findings An optimized lateral overlap of about 60-70% results in an average surface roughness of 8-16 µm along all printed directions of the X–Y stage. The single-layer thickness and dimensional accuracy of the proposed FW-LMD process was about 40-80 µm and ±30 µm, respectively. A dense cross-sectional morphology was observed for the multilayer stacking without any visible voids, pores or defects present between the layers. X-ray diffraction confirmed a majority austenite phase with small ferrite phase formation that occurs at the junction of the vertically stacked beads, as confirmed by the electron backscatter diffraction (EBSD) analysis. Tensile tests were performed and an ultimate tensile strength of about 700-750 MPa was observed for all samples. Furthermore, multilayer printing of different shapes with improved surface finish and thin-walled and inclined metal structures with a minimum achievable resolution of about 500 µm was presented. Originality/value To the best of the authors’ knowledge, this is the first study to report a directed energy deposition process using a fine metal wire with a diameter of 100 µm and can be a possible solution to improving surface finish and reducing the “stair-stepping” effect that is generally observed for wires with a larger diameter. The AM process proposed in this study can be an attractive alternative for 3D printing of high-precision metal components and can find application for rapid prototyping in a range of industries such as medical and automotive, among others.

Optimising the FDM additive manufacturing process to achieve maximum tensile strength: a state-of-the-art review

2019 ◽  
Vol 25 (6) ◽  
pp. 953-971 ◽  
Author(s):  
Tessa Jane Gordelier ◽  
Philipp Rudolf Thies ◽  
Louis Turner ◽  
Lars Johanning
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Material Selection ◽  
Single Point ◽  
Air Gap ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Maximum Tensile Strength ◽  
Fused Deposition ◽  
Raster Angle

Purpose Additive manufacturing or “3D printing” is a rapidly expanding sector and is moving from a prototyping service to a manufacturing service in its own right. With a significant increase in sales, fused deposition modelling (FDM) printers are now the most prevalent 3D printer on the market. The increase in commercial manufacturing necessitates an improved understanding of how to optimise the FDM printing process for various product mechanical properties. This paper aims to identify optimum print parameters for the FDM process to achieve maximum tensile strength through a review of recent studies in this field. Design/methodology/approach The effect of the governing printing parameters on the tensile strength of printed samples will be considered, including material selection, print orientation, raster angle, air gap and layer height. Findings The key findings include material recommendations, such as the use of emerging print materials like polyether-ether-ketone (PEEK), to produce samples with tensile strength over 200 per cent that of conventional materials such as acrylonitrile butadiene styrene (ABS). Amongst other parameters, it is shown that printing in the “upright” orientation should be avoided (samples can be up to 50 per cent weaker in this orientation) and air gap and raster width should be concurrently optimised to ensure good “inter-raster” bonding. The optimal choice of raster angle depends on print material; in ABS for example, selecting a 0° raster angle over a 90° angle can increase tensile strength by up to 100 per cent. Originality/value The paper conclusions provide researchers and practitioners with an up-to-date, single point reference, highlighting a series of robust recommendations to optimise the tensile strength of FDM-printed samples. Improving the mechanical performance of FDM-printed samples will support the continued growth of this technology as a viable production technique.

Tensile properties of aluminium 4047A built in droplet-based metal printing

2019 ◽  
Vol 25 (2) ◽  
pp. 427-432 ◽  
Author(s):  
Benjamin Himmel ◽  
Dominik Rumschoettel ◽  
Wolfram Volk
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Ultimate Tensile Strength ◽  
Uniform Elongation ◽  
Interface Temperature ◽  
Content Type ◽  
Metal Printing ◽  
Main Effect ◽  
First Time

Purpose Directly printing molten metal droplets on a build platform to create full dense metal parts is a promising additive manufacturing process. This study aims of to analyse the effects of the thermal conditions on the resulting tensile properties of parts made from aluminium 4047A built in droplet-based metal printing. Design/methodology/approach A drop-on-demand print head with pneumatic actuation is used to eject droplets on a nickel sheet mounted on the heated build platform. Tensile specimens are machined from cuboid blocks built by successive droplet deposition and tested in a universal testing machine. The ultimate tensile strength, uniform elongation and yield strength are evaluated and presented. Micro-sections are taken from the printed blocks to examine the internal pores and the metal’s microstructure. Findings With an increase in the interface temperature the uniform elongation increases from 0.5 to 12%, while the yield strength decreases from 130 to 90 MPa. The ultimate tensile strength increases from 130 MPa to a maximum of 190 MPa at an interface temperature of 530º C and slightly falls for higher interface temperatures. Those values are in the same range as conventionally casted parts of the same alloy. The authors’ hypothesis is that the main effect responsible for the mechanical properties is the wetting of solid material by the liquid droplet and not remelting, as has been reported in literature. Originality/value To the best of the authors’ knowledge, this is the first time that mechanical properties of aluminium 4047A built by a droplet-based additive manufacturing process are published for different interface temperatures. It is also the first time that the main effect on mechanical properties is attributed to wetting instead of remelting.

Development of additive manufacturing technology based on selective metal-polymer composite formation

2018 ◽  
Vol 24 (1) ◽  
pp. 52-68 ◽  
Author(s):  
Marlon Wesley Machado Cunico ◽  
Jonas de Carvalho
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Strength ◽  
Polymeric Material ◽  
Material Removal ◽  
New Technology ◽  
Content Type ◽  
Material Development ◽  
Composite Formation ◽  
Residual Material ◽  
Metal Polymer

Purpose During the past years, numerous market segments have increasingly adopted additive manufacturing technologies for product development and complex parts design. Consequently, recent developments have expanded the technologies, materials and applications in support of emerging needs, in addition to improving current processes. The present work aims to propose and characterise a new technology that is based on selective formation of metal-polymer composites with low power source. Design/methodology/approach To develop this project, the authors have divided this work in three parts: material development, process feasibility and process optimisation. For the polymeric material development, investigation of metallic and composite materials assessed each material’s suitability for selective composite formation besides residual material removal. The primary focus was the evaluation of proposed process feasibility. The authors applied multivariable methods, where the main responses were line width, penetration depth, residual material removal feasibility, layer adherence strength, mechanical strength and dimensional deviation of resultant object. The laser trace speed, distance between formation lines and laser diameter were the main variables. Removal agent and polymeric material formulation were constants. In the last part of this work, the authors applied a multi-objective optimisation. The optimisation objectives minimized processing time and dimensional deviation while maximizing mechanical strength in xy direction and mechanical strength in z direction. Findings With respect to material development, the polymeric material tensile strength was found between 30 and 45 MPa at break. It was also seen that this material has low viscosity before polymerized (between 2 and 20 cP) essential for composite formation and complete material removal. In that way, the authors also identified that the residual material removal process was possible by redox reaction. In contrast with that the final object was marked by the polymer which covers the metallic matrix, protecting the object protects against chemical reactions. For the feasibility study, the authors identified the process windows for adherence between composite layers, demonstrating the process feasibility. The composite mechanical strength was shown to be between 120 and 135 MPa in xy direction and between 35 and 45 MPa in z direction. In addition, the authors have also evidenced that the geometrical dimensional distortion might vary until 5 mm, depending on process configuration. Despite that, the authors identified an optimised configuration that exposes the potential application of this new technology. As this work is still in a preliminary development stage, further studies are needed to be done to better understand the process and market segments wherein it might be applied. Originality/value This paper proposed a new and innovative additive manufacturing technology which is based on metal-polymer composites using low power source. Additionally, this work also described studies related to the investigation of concept feasibility and proposed process characterisation. The authors have focused on material development and studied the functional feasibility, which at the same time might be useful to the development of other additive manufacturing processes.

scholarly journals Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Rolling Direction ◽  
Laser Melting ◽  
Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

Vibratory weld conditioning during gas tungsten arc welding of al 5052 alloy on the mechanical and micro-structural behavior

2020 ◽  
Vol 17 (6) ◽  
pp. 831-836
Author(s):  
M. Vykunta Rao ◽  
Srinivasa Rao P. ◽  
B. Surendra Babu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Welded Joints ◽  
Great Influence ◽  
Welding Process ◽  
Microstructural Characterization ◽  
Content Type ◽  
Average Grain Size

Purpose Vibratory weld conditioning parameters have a great influence on the improvement of mechanical properties of weld connections. The purpose of this paper is to understand the influence of vibratory weld conditioning on the mechanical and microstructural characterization of aluminum 5052 alloy weldments. An attempt is made to understand the effect of the vibratory tungsten inert gas (TIG) welding process parameters on the hardness, ultimate tensile strength and microstructure of Al 5052-H32 alloy weldments. Design/methodology/approach Aluminum 5052 H32 specimens are welded at different combinations of vibromotor voltage inputs and time of vibrations. Voltage input is varied from 50 to 230 V at an interval of 10 V. At each voltage input to the vibromotor, there are three levels of time of vibration, i.e. 80, 90 and 100 s. The vibratory TIG-welded specimens are tested for their mechanical and microstructural properties. Findings The results indicate that the mechanical properties of aluminum alloy weld connections improved by increasing voltage input up to 160 V. Also, it has been observed that by increasing vibromotor voltage input beyond 160 V, mechanical properties were reduced significantly. It is also found that vibration time has less influence on the mechanical properties of weld connections. Improvement in hardness and ultimate tensile strength of vibratory welded joints is 16 and 14%, respectively, when compared without vibration, i.e. normal weld conditions. Average grain size is measured as per ASTM E 112–96. Average grain size is in the case of 0, 120, 160 and 230 is 20.709, 17.99, 16.57 and 20.8086 µm, respectively. Originality/value Novel vibratory TIG welded joints are prepared. Mechanical and micro-structural properties are tested.

scholarly journals Effect of Filler Metal Type on Microstructure and Mechanical Properties of Fabricated NiAl Bronze Alloy Using Wire Arc Additive Manufacturing System

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 513
Author(s):  
Jae Won Kim ◽  
Jae-Deuk Kim ◽  
Jooyoung Cheon ◽  
Changwook Ji
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Metal Wire ◽  
Cold Metal Transfer ◽  
Metal Type ◽  
Cold Metal ◽  
Wire Arc Additive Manufacturing

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κIII structure with β´ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κIII structure in between.

Fabrication of circular cooling channels by cold metal transfer based wire and arc additive manufacturing

2021 ◽  
pp. 095440542199561
Author(s):  
Shaohua Han ◽  
Zhongzhong Zhang ◽  
Pengxiang Ruan ◽  
Shiwen Cheng ◽  
Dingqi Xue
Keyword(s):  
Additive Manufacturing ◽  
High Energy ◽  
Cooling Effect ◽  
High Deposition Rate ◽  
Cooling Channel ◽  
Conformal Cooling Channel ◽  
Conformal Cooling ◽  
Energy Beam ◽  
Cooling Channels ◽  
Straight Line

Additive manufacturing has been proven to be a promising technology for fabricating high-performance dies, molds, and conformal cooling channels. As one of the manufacturing methods, wire and arc additive manufacturing displays unique advantages of low cost and high deposition rate that are better than other high energy beam-based ones. This paper presents a preliminary study of fabricating integrated cooling channels by CMT-based wire and arc additive manufacturing process. The deposition strategies for fabricating circular cross-sectional cooling channels both in conformal and straight-line patterns have been investigated. It included optimizing the welding torch angle, fabricating the enclosed semicircle structure and predicting the collision between the torch and constructed part. The cooling effect test was also conducted on both the conformal cooling channel and straight-line cooling channel. The results affirmed a higher cooling efficiency and better uniform cooling effect of the conformal cooling channel than straight-line cooling channel.

scholarly journals Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon Fibers

2019 ◽  
Vol 3 (2) ◽  
pp. 35 ◽  
Author(s):  
Miguel Reis Silva ◽  
António M. Pereira ◽  
Nuno Alves ◽  
Gonçalo Mateus ◽  
Artur Mateus ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Carbon Fibers ◽  
Low Cost ◽  
Deposition Process ◽  
Processing Parameters ◽  
Yarn Diameter ◽  
Thermoplastic Matrix ◽  
Anisotropic Mechanical Properties ◽  
Long Carbon Fiber

This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.

The effect of vibratory conditioning on tensile strength and microstructure of 1018 mild steel

2020 ◽  
Vol 17 (6) ◽  
pp. 837-844 ◽  
Author(s):  
Venkata Suresh Bade ◽  
Srinivasa Rao P. ◽  
Govinda Rao P.
Keyword(s):  
Tensile Strength ◽  
Mild Steel ◽  
Fusion Zone ◽  
Dc Motor ◽  
Grain Structure ◽  
Internal Stresses ◽  
Skilled Workers ◽  
Mechanical Vibrations ◽  
Content Type ◽  
Weld Defects

Purpose The purpose of this paper is to investigate the prominence of mechanical excitations at the time of welding. In the past years, the process of welding technology has expanded its influence in manufacturing. The crucial drawback of conventional welding is prompted by internal stresses and distortions, which is the focal reason for weld defects. These weld defects can be diminished by the process called post-weld heat treatment (PWHT), which consumes more working hours and needs skilled workers. To replace these PWHT processes, mechanical vibrations are introduced during the process of welding to diminish these weld defects. Design/methodology/approach In the current research, the mechanical vibrations are transferred to weld-pool through vibro-motor and DC motor connected to the electrode. As per standards, the tensile test specimens were prepared for welding with different voltages of vibro-motor and DC motor respectively. The weld joints were tested for tensile strength and analyzed the microstructure at the fusion zone. Findings Melt-ability at fusion zone of 1018 mild steel was investigated by the single-stroke intense heat process of fusion welding. It is observed that the mechanical vibrations technique has a profound influence on the enhancement of the fusion zone characteristics and grain structure. The peak value of the tensile strength is observed at 100 s of vibration, 190 V of vibro-motor voltage and 18 V of electrode voltage. The tensile strength of the welded joints with vibrations is increased up to 22.64% when it is compared with conventional welding. The enhancement of the tensile strength of the weld bead was obtained because of the formation of fine grain structure. So, mechanical vibrations are identified as the most convenient method for improving the mild steel alloys weld quality. Originality/value A novel approach called mechanical vibrations during the process of welding is implemented for fusion zone refinement.

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