Input: Several grades of metallic strips are, however, commercially available but not yet largely utilized in DED.

metallic

DED


Input: This paper introduces a newly developed laser strip cladding process, which can be used for surfacing, repair and additive manufacturing.

laser

cladding

additive manufacturing

be


Input: Cladding tests consisted of single-layer single- and multi-bead tests on planar and round bar type base materials using a 30 mm wide solid Alloy 625 strip.

Cladding

mm

materials

Alloy


Input: The results showed that with 8 kW laser power 34 mm wide and ˜2 mm thick single beads on steel could be produced with low dilution and fusion bond with high deposition (8 kg/h) rates.

laser power

mm

mm

beads

steel

be

fusion

deposition


Input: Corrosion performance of clad deposit was influenced by the inhomogeneous distribution of intermixed iron from the base material on a test surface.

Corrosion

distribution

surface

iron

material


Input: In addition to high productivity, the developed process takes advantage of large build volume (> 1 m3) and full material utilization as well as clean process conditions.

productivity

process

process

build volume

material utilization

as

as


Input: Additive manufacturing has the potential to revolutionize the production of metallic components as it yields near net shape parts with complex geometries and minimizes waste.

Additive manufacturing

production

near net shape

metallic

as

components

complex geometries


Input: At the present day, additively manufactured components face qualification and certification challenges due to the difficulty in controlling defects.

additively manufactured

face

defects


Input: This has driven a significant research effort aimed at better understanding and improving processing controls–yielding a plethora of in-situ measurements aimed at correlating defects with material quality metrics of interest.

research

in-situ

defects

material


Input: In this work, we develop machine-learning methods to learn correlations between thermal history and subsurface porosity for a variety of print conditions in laser powder bed fusion.

porosity

print

laser powder bed fusion


Input: Un-normalized surface temperatures (in the form of black-body radiances) are obtained using high-speed infrared imaging and porosity formation is observed in the sample cross-section through synchrotron x-ray imaging.

surface

infrared

sample

imaging

imaging

porosity

synchrotron


Input: To demonstrate the predictive power of these features, we present four statistical machine-learning models that correlate temperature histories to subsurface porosity formation in laser fused Ti-6Al-4V powder.

power

temperature

porosity

laser

fused

powder


Input: The aircraft engine industry manufactures many ring-like metal parts of large diameter but small cross-sectional area.

industry

metal

diameter

area


Input: Designers of these parts require increasingly complex geometries for improved aerodynamic efficiency and cooling while manufacturers of these parts require larger and faster equipment for high productivity and low cost.

complex geometries

productivity

cooling

equipment


Input: The combination of these industrial requirements inspired the development of a new Direct Metal Laser Melting (DMLM) architecture, reported here, which incorporates a rotating powder bed.

industrial

architecture

Direct Metal Laser Melting

DMLM

powder bed


Input: The system coordinates the rotational motion of the powder bed with an ascending laser scanner and recoater to build parts in a helical fashion.

coordinates

build

powder bed

laser

fashion


Input: A single-point powder feeder delivers metal powder near the inner radius of an annular build volume, and a recoater spreads the powder to the outer radius in a “snow plow” fashion.

powder

metal powder

powder

feeder

build volume

fashion


Input: Encoder feedback from both the rotational stage and the galvanometers assures accuracy of the laser scan path.

Encoder

accuracy

laser scan


Input: Build rates were shown to triple conventional DMLM systems while powder requirements were decreased by more than 4x.

Build rates

DMLM

powder


Input: The production of magnesium alloy WE43 was achieved by selective laser melting (SLM).

production

selective laser melting

SLM

magnesium alloy


Input: The alloy was investigated after SLM, hot isostatic pressing (HIP), and solutionising heat treatment.

alloy

SLM

hot isostatic pressing

HIP

heat treatment


Input: The microstructure and corrosion behaviour of the specimens were carefully characterised, whilst assessed and contrast relative to the conventionally cast alloy counterpart.

microstructure

corrosion

cast

alloy


Input: The SLM prepared specimens possess a unique microstructure comprising fine grains growing with a strong [0001] texture along the building direction with a low fraction of process-induced and metallurgical defects, reaching < 0.1%, after optimising the SLM parameters and the HIP treatment.

SLM

SLM

HIP

microstructure

grains

fraction

defects

parameters

texture

building direction

metallurgical


Input: Electrochemical measurements demonstrated that the SLM prepared WE43 is cathodically more active as compared with its cast counterpart.

Electrochemical measurements

SLM

cast

as


Input: It is proposed that this behaviour is due to a high density of zirconium-rich oxide particles uniformly distributed throughout the alloy microstructure as well as the alterations in the chemical composition of the solid-solution matrix originating from the high cooling rates of SLM.

density

oxide

alloy

as

as

chemical composition

cooling rates

SLM


Input: It was also noted that the oxide particles are mainly sourced by powder.

oxide

powder


Input: The present results suggest that the corrosion of SLM prepared Mg alloys could be greatly improved once the influence of powder characteristics is further understood and controlled.

corrosion

SLM

Mg alloys

be

powder


Input: A three-dimensional (3D) thermomechanical coupled model for Laser Solid Forming (LSF) of Ti-6Al-4V alloy has been calibrated through experiments of 40-layers metal deposition using different scanning strategies.

three-dimensional

thermomechanical

model

calibrated

metal deposition

scanning strategies

Laser

Forming

Ti-6Al-4V alloy


Input: The sensitivity analysis of the mechanical parameters shows that the thermal expansion coefficient as well as the elastic limit of Ti-6Al-4V have a great impact on the mechanical behavior.

sensitivity analysis

impact

mechanical

mechanical

thermal expansion coefficient

elastic

as

as


Input: Using the validated model and optimal mechanical parameters, the evolution of thermo-mechanical fields in LSF has been analyzed.

model

evolution

thermo-mechanical

mechanical


Input: It has been found that the stresses and distortions develop in two stages, after the deposition of the first layer and during the cooling phase after the manufacturing of the component.

deposition

layer

cooling

manufacturing

component


Input: The cooling phase is the responsible of 70% of the residual stresses and 60% of the total distortions.

cooling

residual stresses


Input: The analyses indicate that by controlling the initial substrate temperature (pre-heating phase) and the final cooling phase it is possible to mitigate both distortion and residual stresses.

substrate

phase

distortion

cooling

residual stresses


Input: The results show that increasing the pre-heating temperature of the substrate is the most effective way to reduce the distortions and residual stresses in Additive Manufacturing.

temperature

substrate

residual stresses

Additive Manufacturing


Input: A novel method that combines additive manufacturing (AM) and atomic layer deposition (ALD).

additive manufacturing

AM

atomic layer deposition


Input: Space-grading plastic AM components enables faster and more complex designs.

plastic

AM

designs


Input: The ALD coating seems to improve the flow properties of the tested AM fluidics restrictor.

coating

properties

AM


Input: Results also indicate an improved structural integrity.

structural integrity


Input: There were indications the coating might slightly mitigate outgassing at higher temperatures, but results are inconclusive.

coating

temperatures


Input: Space technology has been an early adopter of additive manufacturing (AM) as a way of quickly producing relatively complex systems and components that would otherwise require expensive and custom design and production.

technology

additive manufacturing

AM

production

as

components

design


Input: Space as an environment and long-term survivability pose challenges to materials used in AM and these challenges need to be addressed.

as

be

materials

AM


Input: Atomic layer deposition (ALD) is an effective coating method enabling conformal and precise coating of the complete AM print.

Atomic layer deposition

AM

coating

coating


Input: This work analyses how an ALD coating of aluminium oxide on acrylonitrile butadiene styrene (ABS) and polyamide PA 2200 plastic AM prints benefits and protects them.

coating

aluminium

acrylonitrile butadiene styrene

ABS

polyamide

plastic

PA

AM


Input: AM was performed with material extrusion and selective laser sintering methods that are commonly used.

AM

material extrusion

selective laser sintering


Input: Tests were performed with a simple bang-bang controller test setup and a mass spectrometer, and the existence of the coating was confirmed with scanning electron microscope imaging.

simple

controller

scanning electron microscope

coating

imaging


Input: First known study on design freedom offered by 3D Sand-Printing process to redesign sprue in metal casting which causes agitation in melt flow.

design freedom

process

agitation

melt flow

sprue

metal

casting


Input: Numerical model and optimization algorithm for novel sprue profiles are developed to reduce casting defects by 99.5%.

model

optimization algorithm

sprue

profiles

casting


Input: Mechanical strength in castings improved by 8.4% when compared to traditional gating.

Mechanical strength


Input: The opportunity to improve the quality of metal castings by enabling fabrication of complex gating systems via 3D Sand-Printing (3DSP) has been recently established.

quality

gating systems

metal

fabrication


Input: Among the different components of a gating system (often called rigging), sprue design offers a major opportunity to exploit the unlimited geometric freedom offered by 3DSP process.

components

sprue

gating system

geometric freedom

process

design


Input: In this study, conventional principles of casting hydrodynamics is advanced by validated novel numerical models for novel sprue designs to improve melt flow control.

casting

sprue

designs

melt flow


Input: Multiple approaches to integrate 3DSP into conventional manufacturing to fabricate complex gating systems through “Hybrid Molding” are presented.

conventional manufacturing

fabricate

Molding

gating systems


Input: 3DSP molds featuring two optimized sprue profiles and a benchmark straight sprue are fabricated to pour 17-4 stainless steel.

molds

sprue

sprue

profiles

benchmark

fabricated

17-4 stainless steel


Input: Computed tomography scans (CT) shows that parabolic sprue casting (PSC) and conical-helix sprue casting (CHSC) reduced overall casting defects by 56% and 99.5% respectively when compared to straight sprue casting (SSC).

Computed tomography

CT

sprue

sprue

sprue

casting

casting

casting

casting


Input: Scanning electron microscopy (SEM) analysis confirms the presence of globular oxide inclusions and that PSC and CHSC exhibits 21% and 35% reduced inclusion when compared to the SSC.

Scanning electron microscopy

SEM

oxide inclusions

inclusion


Input: Three point flexural testing reveals that CHSC and PSC exhibits an increase of 8.4% and 4.1% respectively in average ultimate flexural strength than SSC.

testing

average

flexural strength


Input: The findings from this study demonstrate that numerically optimized gating systems that can only be fabricated via 3DSP have the potential to significantly improve both mechanical and metallurgical performance of sand castings.

gating systems

be

mechanical

metallurgical

sand castings


Input: With increasing industrial application of additive manufacturing technologies, such as selective laser melting, the requirements concerning the processes’ capabilities like productivity, robustness, part quality and the range of processable materials are increasing as well.

industrial

additive manufacturing

as

as

laser

processes

productivity

quality

materials

robustness

range


Input: But due to high cooling rates, high thermal gradients and a layer-wise processing, parts produced by selective laser melting are subject to different kinds of defects.

cooling rates

thermal gradients

selective laser melting

defects


Input: These defects commonly lead to high porosity, distortion, cracking and rough surfaces.

defects

distortion

cracking

surfaces

lead

porosity


Input: But when a second beam is used to heat the vicinity of the melt pool a homogenization of the temperature field, a reduction of the cooling speeds within the melt pool and in its vicinity as well as an improved wetting behavior is possible.

beam

heat

reduction

melt pool

melt pool

as

as

homogenization

cooling

temperature


Input: A proof of concept is shown, discussing general trends and possibilities, like increased surface qualities or dense microstructures with low amounts of remelting, when these strategies are elaborated.

trends

surface qualities

microstructures


Input: Binder jet printed components typically have low overall density in the green state and high shrinkage and deformation after heat treatment.

Binder

components

density

shrinkage

deformation

heat treatment


Input: It has previously been demonstrated that, by including nanoparticles of the same material in the binder, these properties can be improved as the nanoparticles can fill the interstices and pore throats between the bed particles.

nanoparticles

properties

nanoparticles

material

binder

be

as

pore

bed


Input: The beneficial effects from using these additive binder particles can be improved by maximising the binder particle size, enabling the space within the powder bed to be filled with a higher packing efficiency.

additive

be

binder

be

particles

powder bed


Input: The selection of maximum particle size for a binder requires detailed knowledge of the pores and pore throats between the powder bed particles.

particle

particles

binder

pores

pore

powder bed


Input: In this paper, a raindrop model is used to determine the critical radius at which binder particles can pass between pores and penetrate the bed.

model

binder

pores

bed


Input: The model is validated against helium psychometry measurements and binder particle drop tests.

model

helium

binder


Input: It is found that the critical radius can be predicted, with acceptable accuracy, using a linear function of the mean and standard deviation of the particle radii.

be

accuracy

standard deviation

particle


Input: Percolation theory concepts have been employed in order to generalise the results for powder beds that have different mean particle sizes and size distributions.

powder beds

particle

distributions


Input: The results of this work can be employed to inform the selection of particle sizes required for binder formulations, to optimise density and reduce shrinkage in printed binder jet components.

be

binder

binder

particle

shrinkage

density

components


Input: Electron beam melting (EBM) is a metal powder bed fusion additive manufacturing (AM) technology that makes possible the fabrication of three-dimensional near-net-shaped parts directly from computer models.

Electron beam melting

EBM

metal powder bed fusion additive manufacturing

AM

fabrication

technology

three-dimensional

computer


Input: EBM technology has been continuously evolving, optimizing the properties and the microstructure of the as-fabricated alloys.

EBM

properties

microstructure

alloys


Input: Ti-6Al-4V ELI (Extra Low Interstitials) titanium alloy is the most widely used and studied alloy for this technology and is the focus of this work.

titanium alloy

alloy

technology


Input: Several research works have been completed to study the mechanisms of microstructure formation, evolution, and its subsequent influence on mechanical properties of the alloy.

research

microstructure

evolution

mechanical properties

alloy


Input: In this work, samples fabricated at different locations, orientations, and distances from the build platform have been characterized, studying the relationship of these variables with the resulting material intrinsic characteristics and properties (surface topography, microstructure, porosity, micro-hardness and static mechanical properties).

samples fabricated

orientations

properties

surface topography

microstructure

mechanical properties

build platform

material

porosity


Input: This study has revealed that porosity is the main factor controlling mechanical properties relative to the other studied variables.

porosity

mechanical properties


Input: Therefore, in future process development, decreasing the porosity should be considered the primary goal in order to improve mechanical properties.

process

mechanical properties

porosity

be


Input: In the rapidly growing field of Additive Manufacturing (AM), the Laser Directed Energy Deposition (L-DED) process is the focus of intense technical attention due to its potential to generate high quality components with location specific composition and microstructural control.

Additive Manufacturing

AM

Laser Directed Energy Deposition

process

quality

composition

microstructural

components


Input: Despite the variety of experimental and modelling efforts devoted to the subject, no studies directly observe the interactions between individual powder particles and the liquid pool of metal at a high enough temporal frequency to characterize these discrete contact events.

experimental

modelling

powder particles

metal

contact


Input: Video images reveal that particles often impact and float on the surface of the melt pool for several hundreds of microseconds before melting into it.

images

particles

impact

surface

melt pool

melting


Input: Further incoming particles were observed to rebound from the melt pool by these floating particles.

particles

particles

melt pool


Input: Through modelling this process analytically, particle self-shielding is shown to impose unavoidable upper limits on overall powder capture efficiency for the L-DED process.

modelling

process

particle

limits

process

powder


Input: High entropy alloy AlCoCrFeNi was obtained by selective electron beam melting (SEBM).

alloy

selective electron beam melting

SEBM


Input: The mechanical properties of SEBM specimens were improved compared with those of the cast specimen.

mechanical properties

SEBM

cast


Input: The pitting potential of the AlCoCrFeNi SEBM specimens in artificial seawater was slightly lower than that of the cast specimen.

pitting

SEBM

cast


Input: The properties of the product were influenced by the microstructure evolution in the SEBM process.

properties

microstructure evolution

process

SEBM


Input: Additive manufacturing is expected to be the manufacturing method for components made with high-entropy alloys (HEAs).

Additive manufacturing

manufacturing

be

alloys

components


Input: In this study, the mechanical and electrochemical behaviors were investigated for equi-molar HEA (AlCoCrFeNi) obtained with selective electron beam melting (SEBM).

mechanical

electrochemical

selective electron beam melting

SEBM


Input: The mechanical properties of SEBM products were improved compared with those of a cast specimen.

mechanical properties

SEBM

cast


Input: Electrochemical measurements in artificial seawater revealed the corrosion behaviors of HEA (AlCoCrFeNi).

Electrochemical measurements

corrosion behaviors


Input: The pitting potential of SEBM specimens (0.112 V vs. Ag/AgCl) was lower than that of a cast specimen (0.178 V vs. Ag/AgCl).

pitting

SEBM

cast

V

V


Input: The mechanical and electrochemical properties of SEBM products were influenced by the phase morphologies formed during the SEBM process.

mechanical

electrochemical

phase morphologies

process

SEBM

SEBM


Input: This paper aims to understand the formation and the effect of residual stress on selective laser melting (SLM) parts.

residual stress

selective laser melting

SLM


Input: SLM is a powder bed based additive manufacturing (AM) process and can be compared to a laser welding process.

SLM

additive manufacturing

AM

laser welding

powder bed

process

be


Input: Due to the high temperature gradients and the densification ratio, which are characteristic of this process, residual stresses occur.

temperature gradients

densification

process

residual stresses


Input: The investigation of residual stress is performed using X-ray diffraction (XRD) for samples made of austenitic stainless steel AISI 316L (EN 1.4404).

residual stress

X-ray diffraction

XRD

samples

austenitic stainless steel


Input: This research examines residual stress at different depths and at two outer surfaces.

research

surfaces

residual stress


Input: For the measurement of stresses at different depths, the samples’ surface layers were removed by electropolishing.

measurement

samples

surface

electropolishing


Input: At sufficiently large distances from the top surface, the stresses in the area of the edge layer initially increase strongly and then decline again.

surface

area

layer


Input: The value and orientation of the resulting main stress components are dependent on the examined layer.

orientation

stress

components

layer


Input: At the top surface, the residual stresses are higher in scan direction than in perpendicular direction.

surface

residual stresses


Input: In contrast, at the lateral surface the maximum main stress is perpendicular to the scan and parallel to the building direction.

surface

stress

building direction


Input: These two cases can be described very well by the two mechanisms in SLM, namely the temperature gradient mechanism (TGM) and the cool-down phase.

be

SLM

temperature gradient mechanism

TGM

phase


Input: It is also shown that at samples with a relative structural density of > 99%, the residual stress values are independent of the applied energy density.

samples

density

residual stress

energy density


Input: The rheology of a ceramic paste is known to be a key factor in the process of additive manufacturing of ceramic parts via extrusion freeforming.

rheology

ceramic

be

ceramic

process

additive manufacturing

extrusion


Input: The rheological properties of ceramic pastes can be influenced by several formulation parameters.

rheological properties

ceramic

be

parameters


Input: In this study, the mutual influence between formulation parameters, printing properties and mechanical properties of ceramic pastes (Al2O3) and the resulting green bodies are investigated.

parameters

properties

mechanical properties

green bodies

ceramic


Input: Special focus is set on elucidating the origins and causes of the altered paste properties to allow targeted material development of pastes for the use in extrusion freeforming.

set

properties

material

extrusion


Input: Glycerine and nanoparticulate boehmite needles are tested as additives and they successfully improve the printability in the extrusion freeforming process of the paste and compression strength of the green body.

as

additives

printability

extrusion

process

green body

compression strength


Input: Considerable difference in the dependency of the mechanical properties on the formulation parameters was detected after a partial sintering of the green bodies at 1000 °C.

mechanical properties

parameters

green bodies

sintering


Input: Dewatering, shrinkage during drying and a running of the deposited lines could be reduced successfully by adjusting the formulation.

shrinkage

drying

be


Input: The impact of the formulation parameters on the printing performance could be linked to the dependency of the volume flow rate on the ratio of pressure over viscosity.

impact

parameters

printing performance

volume

pressure

be

flow rate

viscosity


Input: Hollow microlattices constitute a model topology for architected materials, as they combine excellent specific stiffness and strength with relative ease of manufacturing.

model

materials

as

specific stiffness

strength

manufacturing


Input: The most scalable manufacturing technique to date encompasses fabrication of a sacrificial polymeric template by the Self Propagating Photopolymer Waveguide (SPPW) process, followed by thin film coating and removal of the substrate.

manufacturing

fabrication

template

Photopolymer

substrate

process

coating


Input: Accurate modeling of mechanical properties (e.g., stiffness, strength) of hollow microlattices is challenging, primarily due to the complex stress state around the hollow nodes and the existence of manufacturing-induced geometric imperfections (e.g.

Accurate

mechanical properties

imperfections

stiffness

strength

stress


Input: In this work, we use a variety of measuring techniques (SEM imaging, CT scanning, etc.

SEM

imaging

CT


Input: ) to characterize the geometric imperfections in a nickel-based ultralight hollow microlattice and investigate their effect on the compressive strength of the lattice.

imperfections

lattice

compressive strength


Input: At the strut level, where a more quantitative description of geometric defects is available, the gathered data is used to build a stochastic field model of geometric imperfections using Proper Orthogonal Decomposition.

strut

quantitative

defects

data

stochastic

model

imperfections

build

Decomposition


Input: Using Monte Carlo simulations, the critical buckling loads of a large set of imperfect bars created using the stochastic model are then extracted by Finite Elements Analysis.

simulations

buckling loads

set

stochastic model

extracted

Finite Elements


Input: The statistics of the buckling strength in artificially generated bars is then used to explain the scatter in the strength of CT-derived bars and its correlation with the lattice strength measured experimentally.

statistics

lattice

buckling strength

strength


Input: Although the quantitative results are specific to microlattices fabricated by SPPW templating, the methodology presented herein is equally applicable to architected materials produced by other manufacturing processes.

quantitative

fabricated

methodology

materials

manufacturing processes


Input: In order to study the special constriction effect and physical process features during compulsively constricted WAAM (CC-WAAM), the dynamic behaviours of arc, droplets, and molten pool were visually investigated.

physical process

dynamic

arc

droplets

molten pool

WAAM


Input: Possible interactions inside the narrow space were discussed to explain the mechanism of the compulsive constriction on ejected plasma and droplets.

mechanism

plasma

droplets


Input: Based on the captured images, the strong radiative emission indicates that the ejected plasma was at high temperature at least 6000 K. As the current increases higher-temperature plasma jets were expected, which would lead to a larger plasma volume in the absence of constriction.

images

plasma

plasma

plasma

emission

temperature

As

lead


Input: The relationship between current and droplet diameters was preliminarily established to enable prediction of the droplet size.

droplet

prediction

droplet size


Input: An important feature of small-size droplets (as low as 0.89 mm) offered CC-WAAM a great potential to improve the precision of the additive manufacturing layers, although the minimum width of the deposited layer is much larger than the droplet diameter due to liquid spreading and accumulation.

feature

droplets

droplet

diameter

as

as

mm

additive manufacturing

precision

deposited layer


Input: The droplets were found to have a slight impact on the molten pool behaviours, which produces stable molten pool shapes.

droplets

impact

molten pool

molten pool


Input: Under the wide-range parameters, the deposited layers showed good appearances, which indicates the good adaptability of this novel technology.

parameters

technology

deposited layers


Input: In this study, laser metal deposition (LMD) was employed to explore a new fabrication process for producing a functionally graded material (FGM) from Ti-6Al-4V to SS316.

laser metal deposition

LMD

fabrication

FGM

functionally graded material


Input: A transition composition route was introduced (Ti-6Al-4V→V→Cr→Fe→SS316) to avoid the intermetallic phases between Ti-6Al-4V and SS316.

transition composition

intermetallic


Input: A thin wall sample was fabricated via LMD by following the transition composition route.

sample

fabricated

transition composition

LMD


Input: Microstructure characterization and composition distribution analyses were performed by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS).

Microstructure

composition

scanning electron microscopy

SEM

EDS


Input: The SEM images depicted the microstructural morphology of the FGM sample.

SEM

images

microstructural

FGM


Input: The element gradient distribution determined by the EDS results may reflect the FGM transition composition route design.

element

distribution

composition

EDS

FGM

design


Input: X-ray diffraction tests were conducted and the results demonstrated that the generation of intermetallic phases effectively avoided following the composition route.

X-ray diffraction

intermetallic

composition


Input: The Vickers hardness test was used to determine the Vickers hardness number (VHN) distribution from Ti-6Al-4V to SS316.

Vickers hardness

Vickers hardness

distribution


Input: The VHN results showed that no significant formation of hard brittle phases occurred in the LMD procedure.

brittle

LMD


Input: Combining metal nanoparticle (NP) printing and additive manufacturing has high potential for integration of 3D conductive elements and electronic devices inside objects.

metal

elements

additive manufacturing


Input: Current processes used to achieve desired electrical resistivity of the printed NP circuits entail a compromise between resistivity, throughput, and thermal damage of the structure.

processes

structure

electrical resistivity

throughput

resistivity

damage


Input: We explore the mechanisms underlying the combination of Fused Filament Fabrication (FFF) of Acrylonitrile Butadiene Styrene (ABS) and Polylactide (PLA) polymer structures, printing of silver NPs (mixed nanowires and nanospheres), and out-of-chamber Intense Pulsed Light (IPL) sintering of the printed circuits.

Fused Filament Fabrication

FFF

sintering

Acrylonitrile Butadiene Styrene

ABS

PLA

polymer

silver


Input: IPL of only-nanosphere based circuits on the FFF-made structure thermally damages the polymer without any resistivity reduction.

structure

reduction

polymer

resistivity


Input: In a significant advance, the addition of nanowires achieves a resistivity several times lesser than the state-of-the-art (13.1 μΩ-cm or 8 x bulk silver) without any thermal damage and within 0.75 s of IPL.

resistivity

damage

state-of-the-art

silver

s


Input: Electromagnetic analysis and Molecular Dynamics simulations show that nanowire addition concurrently reduces IPL temperature and accelerates the kinetics of resistivity reduction.

simulations

temperature

resistivity

reduction


Input: Subsequent FFF over the post-IPL conductive pattern causes a non-monotonic change in resistivity, surprisingly effecting a resistivity reduction down to 11.8 μΩ-cm.

FFF

pattern

reduction

resistivity

resistivity


Input: The developed approach is used to demonstrate multilayer sensing of internal temperature and a light sensing circuit with embedded interconnects.

sensing

sensing

temperature


Input: Finally, we discuss how these insights may guide the creation of a machine tool that creates a seamless form of the proposed process.

machine tool

process


Input: Parts fabricated using additive manufacturing (AM) methods, such as laser-powder bed fusion (L-PBF), receive highly localized heat fluxes from a laser within a purged, inert environment during manufacture.

fabricated

heat fluxes

manufacture

additive manufacturing

AM

bed fusion

L-PBF

as

laser


Input: These heat fluxes are used for melting metal powder feedstock, while remaining energy is transferred to the solidified part and adjoining gas environment.

heat fluxes

gas

melting

powder feedstock


Input: Using computational fluid dynamics (CFD), the local heat transfer between the adjoining shielding gas, laser-induced melt pool and surrounding heat affected zone is estimated.

computational fluid dynamics

CFD

heat transfer

gas

heat affected zone

melt pool


Input: Simulations are performed for the L-PBF of a single layer of Ti-6Al-4 V. Local temperature, temperature gradients, temperature time-rates-of-change (including cooling rates), as well as dimensionless numbers descriptive of important thermophysics, are provided in order to quantify local convective heat transfer for various laser/gas motion directions.

Simulations

L-PBF

layer

temperature

temperature gradients

temperature

cooling rates

as

as

heat transfer


Input: Results demonstrate that L-PBF track heat transfer is highly dependent on relative gas/laser direction which can impact the prior β grain sizes in Ti-6Al-4 V material by up to 10%.

L-PBF

heat transfer

impact

grain sizes

Ti-6Al-4 V

material


Input: It is found that when the laser and gas are moving in the same direction, convection heat transfer is the highest and a ‘leading thermal boundary layer’ exists in front of the laser which is capable of preheating downstream powder for a possible reduction in residual stress formation along the track.

laser

laser

gas

heat transfer

reduction

boundary

preheating

powder

residual stress


Input: Presented results can aid ongoing L-PBF modeling efforts and assist manufacturing design decisions (e.g.

L-PBF

manufacturing

design


Input: scan strategy, laser power, scanning speed, etc.

laser power

scanning speed


Input: )–especially for cases where homogeneous or controlled material traits are desired.

homogeneous

material


Input: Zinc and its alloys constitute the new generation of biodegradable metallic materials for biomedical implants.

Zinc

alloys

metallic materials

biomedical


Input: Biodegradable implants of Zn, customized for the specific patient can be potentially realised through additive manufacturing processes such as selective laser melting (SLM).

implants

Zn

be

as

additive manufacturing processes

SLM

laser


Input: However, Zn is characterized by low melting and boiling points, resulting in high porosity in the build parts.

Zn

melting

porosity

build


Input: In this work, the SLM of pure Zn powder is studied to improve part density.

SLM

Zn powder

density


Input: A flexible prototype SLM system was used to determine process feasibility under different atmospheric conditions.

prototype

process feasibility


Input: Working in a closed chamber under inert gas was found to be inadequate.

closed chamber

inert gas

be


Input: Process stability was obtained in an open chamber with an inert gas jet flow over the powder bed.

Process

inert gas

powder bed


Input: The effect of laser process parameters and powder size was studied in this condition.

laser

parameters

powder


Input: This paper demonstrates a simple, low-cost additive manufacturing technique for fabricating structures compatible with high-density packaging solutions.

simple

additive manufacturing

fabricating


Input: A T-line resonator is characterized to understand the transmission line losses associated with the vertical bends.

resonator

transmission

vertical


Input: Details of the simulation, fabrication, and measurements are presented.

simulation

fabrication


Input: Simulations are carried out using ANSYS High-Frequency Structure Simulator (HFSS®), and structures are fabricated using a polyjet printing process.

Simulations

ANSYS

Structure

fabricated

polyjet

process


Input: The measured results are in good agreement with the simulation results, and overall a good performance is achieved for all the antenna designs.

simulation

performance

designs


Input: Laser powder bed fusion (L-PBF) is the most prominent additive manufacturing (AM) technology for metal part production.

Laser powder bed fusion

L-PBF

additive manufacturing

AM

production

technology

metal


Input: Among the high number of factors influencing part quality and mechanical properties, the inter layer time (ILT) between iterative melting of volume elements in subsequent layers is almost completely unappreciated in the relevant literature on L-PBF.

quality

mechanical properties

volume

layer

melting

L-PBF

elements


Input: This study investigates the effect of ILT with respect to build height and under distinct levels of volumetric energy density (VED) using the example of 316L stainless steel.

investigates

build height

energy density

316L stainless steel


Input: In-situ thermography is used to gather information on cooling conditions during the process, which is followed by an extensive metallographic analysis.

In-situ

process

cooling


Input: Significant effects of ILT and build height on heat accumulation, sub-grain sizes, melt pool geometries and hardness are presented.

build height

sub-grain sizes

heat accumulation

hardness

melt pool

geometries


Input: Furthermore, the rise of defect densities can be attributed to a mutual interplay of build height and ILT.

defect

be

build height


Input: Hence, ILT has been identified as a crucial factor for L-PBF of real part components especially for those with small cross sections.

as

L-PBF

components

cross sections


Input: Crack-free nickel-based single crystal superalloy samples were fabricated via directed energy deposition.

samples

fabricated

directed energy deposition


Input: Hot cracking occurred at high-angle grain boundaries and especially at low-angle grain boundaries.

Hot cracking

grain boundaries

grain boundaries


Input: The existence conditions of the liquid film for hot cracking in CMSX-10 are calculated with analysis models.

hot cracking


Input: The hot cracking mechanism is related to the stability of liquid film, stress concentration and Re-rich precipitations.

hot cracking

stability

stress concentration


Input: Hot cracking is a frequent and severe defect that occurs during the directed energy deposition (DED) of single-crystal superalloys.

Hot cracking

defect

directed energy deposition

DED

superalloys


Input: Understanding the cracking behavior and mechanism is key to avoiding these defects.

cracking

mechanism

defects


Input: Hot cracking occurred at high-angle grain boundaries and especially at low-angle grain boundaries.

Hot cracking

grain boundaries

grain boundaries


Input: Hot cracking was determined to be caused by a stable liquid film, stress concentration, and Re-rich precipitates.

Hot cracking

be

precipitates

stress concentration


Input: The stability of the liquid film depended on dendrite coalescence undercooling which was related to the misorientation angle.

stability

dendrite


Input: The dendrite coalescence undercooling at low-angle grain boundary (misorientation angle 6.9°) was 178 K, which was far higher than the vulnerable temperature interval 38 K for hot cracking within a single dendrite.

dendrite

dendrite

grain boundary

hot cracking

K

K

temperature


Input: Stress concentration provided the driving force for crack initiation and propagation.

Stress concentration

force


Input: Re-rich precipitates promoted crack initiation by a pinning effect on the liquid feed.

precipitates

feed


Input: These findings provide technical support for achieving high-quality additive manufacturing and repair of non-weldable Ni-based single-crystal superalloys.

support

additive manufacturing

superalloys


Input: LMDed Ti-Mo alloy, from elemental powder mixture, presents an almost defect-free feature.

alloy

powder

feature


Input: Phase transition from α to β appears as results of in-situ thermal cycling.

Phase

in-situ

as


Input: Textural density of α phase increases significantly, given to the in-situ thermal cycling.

density

phase

in-situ


Input: The LMDed Ti-Mo present a graded tensile property.

tensile property


Input: In this work, almost dense (over 99.8%) Ti-Mo alloy samples were manufactured by directed energy deposition (DED) from a mixture of pure Ti and pure Mo (7.5 wt.%) powders.

alloy

Ti

Mo

powders

manufactured

directed energy deposition

DED


Input: As a consequence of thermal accumulation and in-situ heat treating during the DED process, as-deposited samples present a graded microstructure along the building direction along with a phase transition from hcp-α Ti to bbc-β Ti.

As

Ti

Ti

in-situ heat

samples

phase

DED

graded microstructure

building direction


Input: Mechanical properties were determined by tensile tests from flat samples harvested at different altitude positions.

Mechanical properties

samples

tensile tests


Input: As altitude increases from the base plate, yield strength decreases from 681 MPa to 579 MPa and ultimate tensile strength from 791 MPa to 686 MPa.

As

yield strength

ultimate tensile strength

MPa

MPa

MPa

MPa


Input: Elongation of the as-deposited material increases from 10% to 25% while the Young’ s modulus keeps a low value of 105 GPa for the entire DEDed sample.

Elongation

GPa

material

s

sample


Input: AM parts are fabricated with intentional inhomogeneities to create codes.

AM parts

fabricated


Input: The controlled and random process variation ensures a unique material structure.

process

material


Input: The L-PBF approach creates random pores by a reduced volume energy density.

L-PBF

pores

volume

energy density


Input: The L-DED approach utilizes the different magnetic permeability of two materials.

permeability

materials


Input: Additive manufacturing technologies enable various possibilities to create and modify the material composition and structure on a local level, but are often prone to undesired defects and inhomogeneities.

Additive manufacturing

material

composition

structure

defects


Input: By controlled and random process variation, unique codes that can be read and authenticated by an eddy current device were produced with the processes of laser powder bed fusion (L-PBF) and laser directed energy deposition (L-DED).

process

processes

be

laser powder bed fusion

L-PBF

laser directed energy deposition


Input: Two approaches are presented: First, volumetric, porous structures with a defined shape are manufactured with L-PBF.

porous

manufactured

L-PBF


Input: Second, coatings are fabricated by L-DED with alternating process parameters, leading to local deviations of the magnetic permeability.

coatings

fabricated

process parameters

permeability


Input: Counterfeiting becomes impossible due to the irreproducible melt pool dynamics.

melt pool


Input: Laser-induced forward transfer (LIFT), a 3D additive manufacturing technique is implemented to fabricate a fully metallic functional micro device.

manufacturing

fabricate

metallic


Input: Digital deposition of both structural and sacrificial metal constituents in the same setup arrangement is achieved.

deposition

metal


Input: The final free-standing structure is released by selective chemical wet etching of the support material.

structure

etching

support material


Input: Using this approach, a chevron-type electro thermal micro-actuator made of gold was successfully fabricated and its functionality was shown in experiment.

gold

fabricated

experiment


Input: Comparison of the measured responses with the model predictions indicates that the thermal conductivity of printed Au is approximately 8 times lower than the bulk value.

model

thermal conductivity

Au


Input: It is a first demonstration of a functional micron scale actuator printed using LIFT.

micron

actuator


Input: In this paper, a predictive model based on a cellular automaton (CA) -finite element (FE) method has been developed to simulate thermal history and microstructure evolution during metal solidification for a laser-based additive manufacturing process.

predictive model

microstructure evolution

CA

element

FE

metal

laser-based additive manufacturing


Input: The macroscopic FE calculation was designed to update the temperature field and simulate a high cooling rate.

macroscopic

FE

designed

temperature

cooling rate


Input: In the microscopic CA model, heterogeneous nucleation sites, preferential growth orientation, and dendritic grain growth were simulated.

CA

heterogeneous nucleation

orientation

grain growth


Input: The CA model was able to show the entrapment of neighboring cells and the relationship between undercooling and the grain growth rate.

CA

cells

grain growth


Input: The model predicted the dendritic grain size, and morphological evolution during the solidification phase of the deposition process.

model

evolution

solidification phase

grain size

deposition process


Input: The grain morphology result has been validated by the experiment.

grain

experiment


Input: SLM process was optimized via polynomial regression model.

SLM

process

regression model


Input: Remelting step between SLM scans led to homogenization of the metal powders.

step

SLM

homogenization

led

metal powders


Input: Si addition increased the tensile strength while maintaining the ductility.

Si

tensile strength

ductility


Input: Interaction between dislocation loops with dislocations strengthened the alloy.

dislocation

dislocations

alloy


Input: Effect of solid solution and dislocation loop on yield strength were quantified.

solid solution

dislocation

yield strength


Input: To widen the applications of new materials in additive manufacturing (AM), the traditional method of printing using pre-alloyed powders should be improved because the pre-alloying process is expensive and makes it difficult to adjust the composition of new materials.

materials

process

composition

materials

additive manufacturing

AM

powders

be


Input: This study investigates the synthesis of a FeCoCrNi high-entropy alloy (HEA) containing 1.5 at.% Si in situ using selective laser melting (SLM).

investigates

in situ

alloy

Si

selective laser melting

SLM


Input: A remelting strategy and process optimization based on polynomial regression modeling allowed for the printing of almost fully dense (99.78%) samples.

process optimization

regression

samples

modeling

fully dense


Input: The samples comprised columnar grains, each containing numerous subgrains of a single-phase face-centered cubic solid solution.

samples

subgrains

columnar grains

solid solution


Input: No precipitation or segregation were observed.

precipitation

segregation


Input: The room temperature tensile properties of the samples were excellent, with yields and tensile strengths reaching 701 ± 14 and 907 ± 25 MPa, respectively, and an elongation at fracture of 30.8 ± 2%.

temperature

properties

samples

MPa

fracture

tensile strengths

elongation


Input: These properties were attributed to solid solution strengthening and novel dislocation loop strengthening mechanism.

properties

dislocation

strengthening mechanism

solid solution


Input: These findings demonstrate that HEAs with a high relative density and good mechanical properties can be directly synthesized by SLM using inexpensive pure metal powders, thereby extending the application potential of AM to manufacture new materials.

relative density

mechanical properties

manufacture

materials

be

pure metal

powders

SLM

AM


Input: This paper presents a new approach for modelling additive layer manufacturing at component scale.

modelling

additive layer manufacturing

component


Input: The approach is applied to powder-bed selective laser melting (SLM) and validated, where the mechanical behaviour of macro-scale industrial components has been predicted and compared with experimental results.

selective laser melting

SLM

mechanical behaviour

predicted

experimental

industrial

components


Input: The novelty of the approach is based on using a calibrated analytical thermal model to derive functions that are implemented in a structural finite element analysis (FEA).

calibrated

model

finite element analysis


Input: The induced distortion in SLM has been compensated for by modifying the initial geometry using FE predicted distortion.

distortion

geometry

distortion

SLM

FE


Input: A newly developed distortion compensation method, based on optical 3D scan measurements, has also been implemented.

distortion compensation

optical


Input: The two distortion compensation methods have been experimentally validated.

distortion compensation

experimentally validated


Input: In summary, the research presented in this paper shows that the mitigation of distortion in SLM is now possible on industrial macro-scale components.

research

distortion

SLM

industrial

components


Input: This paper reports on X-ray tomography of a series of coupon samples (5 mm cubes) produced under different process parameters, for laser powder bed fusion of Ti6Al4V.

X-ray tomography

samples

process parameters

mm

laser powder bed fusion


Input: Different process parameters result in different pore formation mechanisms, each with characteristic pore sizes, shapes and locations within the 5 mm cube samples.

process parameters

cube

pore

pore sizes

mm


Input: While keyhole pores, lack of fusion pores and metallurgical pores have been previously identified and illustrated using X-ray tomography, this work extends beyond prior work to show how each of these not only exist in extreme situations but how they vary in size and shape in the transition regimes.

pores

fusion

transition

metallurgical

X-ray tomography


Input: It is shown how keyhole mode porosity increases gradually with increasing power, and how this depends on the scan speed.

porosity

power

scan speed


Input: Similarly, lack of fusion pores are shown to occur following scan tracks in situations of poor hatch overlap, or a similar but different distribution of lack of fusion porosity due to large layer height spacing, showing respectively vertical and horizontal lack of fusion pore morphologies.

fusion

overlap

distribution

fusion

vertical

fusion

morphologies

layer height


Input: Insights from 3D images allow improvements in parameter choices for optimized density of parts produced by laser powder bed fusion, and generally allow a better understanding of the porosity present in additively manufactured parts.

3D images

parameter

density

porosity

laser powder bed fusion

additively manufactured


Input: This work investigates an additive manufacturing route of producing functional net shaped parts from pre-alloyed magnetic shape-memory Ni-Mn-Ga powders.

investigates

additive manufacturing

powders


Input: Three types of Ni-Mn-Ga powders were used in this investigation: spark eroded in liquid nitrogen (LN2), spark eroded in liquid argon (LAr), and ball milled (BM).

powders

nitrogen

argon

BM

milled


Input: Additive manufacturing via powder bed binder jetting, also known as 3D printing (3DP), was used in this research due to both relatively easy control of part porosity and the possibility to obtain complex shaped parts from Ni-Mn-Ga alloys.

Additive manufacturing

powder bed binder jetting

3D printing

as

alloys

research

porosity


Input: The four-dimension (4D) is created by the predictable change in 3D printed part configuration over time as the result of shape-memory functionality.

predictable

3D printed part

as


Input: Binder jetting of Ni-Mn-Ga powders followed by curing and sintering proved successful in producing net shaped porous structures (spring-like, 3-D hierarchical lattice structures, etc.

Binder jetting

curing

sintering

powders

porous

lattice structures


Input: ) with good mechanical strength.

mechanical strength


Input: Parts with porosities between 24.08% and 73.43% have been obtained by using powders with distinct morphologies.

porosities

powders

morphologies


Input: Thermo-magneto-mechanical trained 3D printed parts obtained from ball milled Ni-Mn-Ga powders showed reversible magnetic-field-induced strains (MFISs) of up to 0.01%.

3D printed parts

milled

powders


Input: The additive manufacturing is a viable technology in solving the design issues of functional parts made of Ni-Mn-Ga magnetic shape-memory alloys (MSMA).

additive manufacturing

technology

design

alloys


Input: Additive manufacturing (AM) technologies are capable of fabricating custom parts with complex geometrical shapes in a short period of time relative to traditional fabrication processes that require expensive tooling and several post processing steps.

Additive manufacturing

AM

fabricating

fabrication

technologies

tooling

post processing


Input: Material extrusion AM, known commercially as Fused Filament Fabrication (FFF) technology, is a widely used polymer AM process, however, the effects of inherent porosity on mechanical strength continues to be researched to identify strength improvement solutions.

Material extrusion AM

Fabrication

FFF

AM process

as

Filament

polymer

be

technology

porosity

mechanical strength

strength


Input: To address the effect of porosity and layer adhesion on mechanical properties (which can sometimes result in 27–35% lower ultimate tensile strength when compared to plastic injection molding), an approach was employed to reinforce 3D printed polycarbonate (PC) parts with continuous carbon fiber (CF) bundles.

porosity

adhesion

ultimate tensile strength

layer

mechanical properties

plastic injection molding

3D printed

PC

continuous carbon fiber


Input: Results demonstrated a maximum of 77% increase in tensile yield strength when PC was reinforced with three CF bundles and micrographs showed multiple regions with zero porosity due to the CF inclusion.

tensile

strength

porosity

PC

inclusion

reinforced


Input: PC with three bundles of CF (modulus of 3.36 GPa) showed 85% higher modulus of elasticity than the neat PC specimens (modulus of 1.82 GPa).

PC

PC

GPa

modulus of elasticity

GPa


Input: The manual placement of CF and its impact on mechanical properties motivated the development of an automated selective deposition method using an ultrasonic embedding apparatus.

impact

mechanical properties

deposition


Input: Substantial technology development towards the embedding process of continuous carbon fiber bundles using ultrasonic energy was achieved in an automated fashion which is complementary of digital manufacturing and novel when compared to other existing processes.

technology

process

fashion

processes

continuous carbon fiber

digital manufacturing


Input: Laser Engineered Net Shaping (LENS™) is a commercially available additive manufacturing technique that was used for one step manufacturing of bimetallic structures of stainless steel and Ti6Al4V (Ti64) alloy.

Laser Engineered Net Shaping

additive manufacturing

manufacturing

step

stainless steel

alloy


Input: In the first approach, direct deposition of Ti64 on SS410 substrate and compositionally graded bimetallic structures were attempted without any intermediate bond layer.

deposition

substrate

layer


Input: In the second approach, an intermediate NiCr bond layer (of thickness ∼750 μm) was deposited to minimize thermal and residual stresses for these bimetallic structures.

layer

residual stresses


Input: Direct deposition of Ti64 was successful only for a couple of layers before the structures were delaminated.

deposition


Input: Compositionally graded bonding was unsuccessful with the formation of brittle intermetallics and related residual stresses causing delamination.

bonding

delamination

brittle

residual stresses


Input: Using an intermediate NiCr layer, bimetallic structures were successfully fabricated.

layer

fabricated


Input: Our work is focused on LENS™ based processing approach and related microstructural evolution towards bimetallic structures.

microstructural evolution


Input: Residual stresses are measured for different deposition patterns.

Residual stresses

deposition


Input: The evolution of residual stresses and distortions are modelled in 3D.

evolution

residual stresses


Input: The effect of convective flow inside the molten pool are examined.

molten pool


Input: Susceptibilities to delamination & warping of Ti-6Al-4V & Inconel 718 are examined.

delamination

warping

Inconel 718


Input: Since the deposition patterns affect the stresses and distortions, we examined their effects on multi-layer wire arc additive manufacturing (WAAM) of Ti-6Al-4V and Inconel 718 components experimentally and theoretically.

deposition

wire arc additive manufacturing

WAAM

Inconel 718

components


Input: We measured residual stresses by hole drilling method in three identical components printed using different deposition patterns.

residual stresses

hole drilling

components

deposition


Input: In order to understand the origin and the temporal evolution of residual stresses and distortion, we used a well-tested thermo-mechanical model after validating the computed results with experimental data for different deposition patterns.

evolution

distortion

thermo-mechanical model

experimental data

deposition

residual stresses


Input: Distortions were also examined based on non-dimensional analysis.We show that printing with short track lengths can minimize residual stresses and distortion among the three patterns investigated for both alloys.

residual stresses

distortion

alloys


Input: Both Ti-6Al-4V and Inconel 718 had similar fusion zone shape and size and were equally susceptible to deformation and warping, although Ti-6Al-4V was relatively less vulnerable to delamination due to its higher yield strength.

Inconel 718

fusion zone

deformation

warping

delamination

yield strength


Input: A dimensionless strain parameter accurately predicted the effects of WAAM parameters on distortion and this approach is especially useful when the detailed thermo-mechanical calculations can not be undertaken.

strain

parameter

parameters

distortion

thermo-mechanical

accurately

WAAM

be


Input: The present work aims to investigate the mechanism of crack initiation induced by internal pores, which are inevitable in additive manufacturing (AM), and the influence of internal pores on the fatigue performance of directed energy deposited (DED) Ti-6.5Al-2Zr-Mo-V. After fatigue test under constant amplitude alternating stress at three stress levels, thirty-one pieces of DED Ti-6.5Al-2Zr-Mo-V specimens were found that cracks initiating from internal pores.

mechanism

pores

pores

fatigue

stress

stress

pores

additive manufacturing

AM

DED

DED

fatigue test


Input: Scanning electron microscope (SEM) and its accessories, such as energy dispersive spectrometry (EDS) and electron backscattered diffraction (EBSD), were used to analyze the characteristics of pore defects and clarify the mechanism of crack initiation.

Scanning electron microscope

SEM

EDS

diffraction

EBSD

as

pore

defects

mechanism


Input: The results show that the specificity of the microstructure affected by the DED process and pore defects, such as segregation of Al and the existence of incomplete grain boundaries, are the main causes of crack initiation.

microstructure

defects

grain boundaries

DED

pore

as

Al


Input: Then, the crack initiation modes were divided into three types, and a classification model was established that can make the effect of pore defects on fatigue life clearer and more intuitive.

classification

defects

pore

fatigue life


Input: The current study presents low cost 3D printed materials with desired electrical charactrestics for RF/microwave applications.

3D printed

electrical


Input: In contrast to the traditional manufacturing techniques of fabrication in electronics, additive manufacturing (AM) is a proper technology for making parts with more advanced complex features.

traditional manufacturing

fabrication

additive manufacturing

AM

electronics

technology


Input: In this study, different 3D printed configurations (infill density and pattern) of materials were printed with Fused Deposition Modeling (FDM) technique to achieve different electrical characteristics, which is used in design and fabrication of RF/microwave structures.

3D printed

Fused Deposition Modeling

FDM

fabrication

infill

density

pattern

materials

electrical

design


Input: By different filling configurations, a range of relative permittivity has been obtained by using Nylon 6 as an input filament for 3D printing.

range

Nylon

as

filament

3D printing


Input: In fact, by use of a known material such as Nylon 6, complex geometries can be 3D printed with different dielectric behavior.

material

as

be

complex geometries

3D printed

dielectric


Input: Mechanical properties of the structures were investigated in order to estimate the quality of the 3D printed parts in electronics’ industry.

Mechanical properties

quality

electronics

3D printed parts

industry


Input: Considering these properties has direct influence on decision making through the design of a 3D structure with required electrical characteristics, while the mechanical properties are also considered.

properties

3D structure

mechanical properties

design

electrical


Input: Binder jetting, a commercial additive manufacturing process that selectively deposits a liquid binder onto a powder bed, can become a viable method to additively manufacture ceramics.

Binder jetting

additive manufacturing process

additively manufacture

liquid binder

powder bed


Input: part density and geometric resolution) have not been investigated and no methodical approach exists for the process development of new materials.

density

resolution

process

materials


Input: In this work, a parametric study consisting of 18 experiments with unique process input combinations explores the influence of seven process inputs on the relative densities of as-printed (green) alumina (Al2O3) parts.

process

process

relative densities

alumina


Input: Sensitivity analyses compare the influence of each input on green densities.

Sensitivity analyses


Input: Multivariable linear and Gaussian process regressions provide models for predicting green densities as a function of binder jetting process inputs.

Gaussian

as

binder jetting


Input: The multivariable linear and Gaussian process regression models indicate that the green densities of alumina builds can be increased by decreasing the recoat speed and increasing the oscillator speed.

Gaussian

regression models

alumina

be


Input: The Gaussian process regression model further suggests that the green densities have nonlinear dependence on the rest of the process parameters.

Gaussian

regression model

process parameters


Input: The models produced can assist operators in selecting process inputs that will result in a desired green density, allowing for the control of porosity in printed parts with a high degree of accuracy.

process

density

porosity

accuracy


Input: The methodology reported in this study can be leveraged for other powder systems and machines to predict and control the porosity of binder jetted parts for applications such as filters, bearings, electronics, and medical implants.

methodology

electronics

be

powder

binder

as

machines

porosity

medical implants


Input: Electron beam melting (EBM) has emerged as an important additive manufacturing technique.

Electron beam melting

EBM

additive manufacturing

as


Input: In this study, Alloy 718 produced by EBM was investigated in as-built and post-treated conditions for microstructural characteristics and hardness.

Alloy

EBM

microstructural

hardness


Input: The post-treatments investigated were hot isostatic pressing (HIP) and combined HIP + heat treatment (HIP + HT) carried out as a single cycle inside the HIP vessel.

hot isostatic pressing

HIP

HIP

heat treatment

HIP

HIP

as


Input: Both the post-treatments resulted in significant decrease in defects inevitably present in the as-built material.

defects

material


Input: The columnar grain structure of the as-built material was found to be maintained after post-treatment, with some sporadic localized grain coarsening noted.

columnar grain

material

be

post-treatment

grain


Input: Although HIP led to complete dissolution of δ and γ′′ phase, stable NbC and TiN (occasionally present) particles were observed in the post-treated specimens.

HIP

phase

particles

TiN


Input: Significant precipitation of γ′′ phase was observed after HIP + HT, which was attributed to the two-step aging heat treatment carried out during HIP + HT.

precipitation

phase

HIP

heat treatment

HIP


Input: The presence of γ′′ phase or otherwise was correlated to the hardness of the material.

phase

correlated

hardness

material


Input: While the HIP treatment resulted in drop in hardness, HIP + HT led to ‘recovery’ of the hardness to values exceeding those exhibited by the as-built material.

HIP

HIP

hardness

hardness

led

material


Input: The cold spray has been shown to be one of the promising additive manufacturing technologies to process Ultra High Molecular Weight Polyethylene (UHMWPE) -metal integrated systems by successfully being able to coat UHMWPE on metals using fumed nano-alumina (FNA) as UHMWPE particle surface modifiers.

be

Polyethylene

metals

as

additive manufacturing

process

particle

Weight


Input: However, the exact mechanism of UHMWPE deposition and role of FNA was widely unknown.

mechanism

deposition


Input: This study aims at identifying the fundamental parameters involved in high strain-rate UHMWPE deposition and their role in successful adhesion by a technique called Isolated Particle Deposition (IPD).

parameters

deposition

Particle

Deposition

adhesion


Input: Major parameters that influenced the UHMWPE deposition efficiency significantly were the particle temperature and velocity and net surface activity of FNA.

parameters

deposition

particle

surface


Input: The stored elastic energy of UHMWPE decreases with increase in temperature, and the deposition criterion for a successful UHMWPE deposition is not to have net stored elastic energy after impact.

elastic

elastic

temperature

deposition

deposition

impact


Input: Effect of FNA was seen in generating H-bonds that helped to establish bridge bond at UHMWPE-substrate interface.

bridge

interface


Input: Innovative fabrication of a < NiCrAlY-IN625 > system by SLM was demonstrated.

fabrication

SLM


Input: Several criteria were used to select the most appropriate SLM process conditions.

SLM

process


Input: As-built coatings exhibited significant dilution characteristic of SLM remelting.

coatings

SLM


Input: Laser power P = 250 W and scanning speed v = 800 mm/s were found optimal.

Laser power

scanning speed


Input: The present study investigated for the first time the feasibility of producing by Selective Laser Melting (SLM) a NiCrAlY bond coat material directly onto an IN625 substrate itself produced by SLM.

feasibility

Selective Laser Melting

SLM

SLM

bond coat

substrate


Input: A typical parameters optimization was conducted by varying laser power (P) and scanning speed (v).

parameters optimization

laser power

scanning speed

P

v


Input: Single-line scanning tracks and two-layer coatings were carried out and analyzed for 15 different P/v conditions.

scanning

coatings


Input: Several criteria were defined for the selection of appropriate SLM parameters.

SLM

parameters


Input: The results showed significant remelting of the underlying substrate, which is a typical feature of SLM manufacturing.

substrate

feature

SLM manufacturing


Input: This led to the formation of an intermediate dilution zone characterized by substantial mixing between IN625 superalloy substrate and NiCrAlY bond coat suggesting excellent metallurgical bonding.

led

bond coat

mixing

metallurgical bonding

substrate


Input: Optimum processing conditions were found for P = 250 W and v = 800 mm/s.

P

v


Input: It produced a dense 242 μm thick bond coat including a 36% dilution zone.

bond coat


Input: The SLMed < NiCrAlY-IN625 > system exhibited a smooth microhardness profile slightly increasing from 275 Hv in the bond coat to 305 Hv in the substrate.

SLMed

microhardness

bond coat

substrate


Input: A progressive Al concentration distribution between the phases and low residual stress levels were found in the system.

Al

distribution

residual stress


Input: This suggested that SLM might be a valuable alternative manufacturing process for bond coat systems promoting excellent adhesion for high temperature applications.

SLM

manufacturing process

be

bond coat

adhesion

temperature


Input: Coupling 3D Discrete Element and Monte Carlo Ray tracing methods to simulate the laser polymer interaction.

Element

laser


Input: Multiphysics coupling: conductive and radiative heat transfers with scattering, phase changes, coalescence, air diffusion, in participating granular medium.

heat transfers

phase

diffusion


Input: Application to additive manufacturing process.

additive manufacturing process


Input: 3D Numerical and experimental validations.

experimental


Input: A numerical framework based on a modified Monte Carlo ray-tracing method and the Discrete Element Method (DEM) is developed to predict the physical behavior of discrete particles during the Powder Bed Fusion (SLS) process.

framework

Discrete Element Method

particles

process

Powder Bed Fusion

SLS


Input: A comprehensive model coupling all major aspects of the underlying physics and the corresponding numerical framework, accounting for radiative heat transfer, heat conduction, sintering and granular dynamics among others, is developed.

model

physics

framework

heat transfer

heat conduction

sintering


Input: The spatially and temporally varying distribution of heat and displacement within the additively manufactured object are captured in detail.

distribution

heat

additively manufactured


Input: The model is validated through the comparison of simulated results with existing experimental results in the literature.

model

experimental


Input: Inconsistent part quality is a challenge to the widespread adoption of powder-bed fusion additive manufacturing.

quality

fusion

additive manufacturing


Input: Previous efforts to monitor the PBF process in situ have been mostly limited to single tracks.

monitor

in situ

PBF


Input: The lack of quantitative, in situ monitoring results from full 3D PBF builds remains a barrier to closed-loop control.

quantitative

in situ

builds

closed-loop control


Input: We track morphology in situ using coherent imaging, providing an immediate check on surface roughness, recoater blade damage, and powder packing density.

morphology

in situ

imaging

surface roughness

damage

density

recoater blade

powder


Input: Defects are corrected through manual closed-loop control; protrusions and depressions identified by in situ imaging are compensated through laser ablation and refilling, respectively, during a 3D build.

Defects

in situ

closed-loop control

imaging

laser ablation


Input: Maximum surface roughness is reduced by 54% and the number of layers with increased surface roughness relative to the steady-state value is reduced by 60%.

surface roughness

surface roughness

number of layers


Input: Manual closed-loop control, successfully achieved using coherent imaging of PBF layer morphology, is an important step towards full feedback control capabilities.

closed-loop control

imaging

PBF

layer

feedback

step


Input: Laser direct deposition model simulates thermal behavior in Ti6Al4V depositions.

Laser

deposition


Input: Cellular automaton model predicts the solidification and distribution of β grains.

model

solidification

distribution

grains


Input: Phase prediction model simulates the solid-state phase transformation of β→α/α’.

Phase

model

solid-state phase


Input: Microhardness was assessed based on the predicted volume fraction of α’.

Microhardness

predicted

fraction


Input: Simulation results were validated with experimental data in good agreement.

Simulation

experimental data


Input: In this paper, a multiphysics and multiscale integrated simulation framework is established to link the thermal history with the microstructural evolution and resulting properties of Ti6Al4V in additive manufacturing processes by combining: (1) a three-dimensional (3D) multiphysics modeling of quasi-steady-state deposition geometry and thermal history in the directed energy deposition (DED) process, (2) a 3D cellular automata modeling of the solidification grain structure, and (3) a diffusion/diffusionless kinetic modeling of solid-state phase transformation and microhardness prediction based on the simulated phase volume fractions.

simulation

modeling

modeling

modeling

framework

microstructural evolution

properties

three-dimensional

deposition

process

solidification grain

solid-state phase

microhardness

phase

additive manufacturing processes

directed energy deposition

DED


Input: By applying to Ti6Al4V, this integrated simulation framework demonstrates its feasibility in modeling complex microstructural evolution and phase transformation during the multi-track DED process.

simulation

modeling

framework

feasibility

microstructural evolution

phase

DED


Input: The simulated track geometry and thermal history agree well with experimental results.

geometry

experimental


Input: Coupled with the extracted temperature profiles and heating/cooling rates, the competitive growth of β grains upon solidification of the molten pool is successfully predicted.

extracted

grains

solidification

molten pool

predicted

profiles


Input: The solid-state β→α/α´ transformation in the fusion zone and heat-affected zone is then captured by the kinetic solid-state phase prediction model.

solid-state

fusion zone

solid-state phase prediction model


Input: With the predicted volume fractions of α and α´ in the final microstructure, the microhardness is assessed, matching the experimental measurements.

predicted

microstructure

microhardness

experimental


Input: Laser sintering (LS), as an additive manufacturing process for production of polymer structures, provides the possibility of directly manufacturing personalized, structural motorcycle components for motor sports.

Laser sintering

additive manufacturing process

production

manufacturing

as

polymer

components


Input: To create such lightweight structures, the wall thickness and position limits of the LS systems need to be investigated in detail.

lightweight structures

wall thickness

limits

be


Input: Appearing process-related flaws such as different amounts of crystallinity, surface roughness, and defects such as pores exhibit dimensions similar to the wall thickness.

flaws

defects

as

as

surface roughness

dimensions

wall thickness


Input: To study the process-related effects on the mechanical properties of 450 tensile test specimens in z-direction, the build areas of two LS systems were screened and a detailed wall thickness investigation was conducted.

mechanical properties

tensile test

z-direction

wall thickness

build areas


Input: In addition, dynamic mechanical analysis, differential scanning calorimetry, and scanning electron microscopy for several wall thicknesses similar to the spot size were conducted.

dynamic mechanical analysis

scanning

scanning electron microscopy

wall thicknesses

spot size


Input: The investigations showed that the Young's moduli and ultimate tensile strengths of the produced specimens of the two commercial EOS systems, P396 and P770, are similar and evenly distributed.

ultimate tensile strengths

EOS


Input: Furthermore, structures with a thickness below 1 mm showed distinctive losses in stiffness, ultimate tensile strength, and elongation at break.

mm

stiffness

ultimate tensile strength

elongation


Input: Selective laser melting (SLM) is an additive manufacturing and 3D printing technology which offers flexibility in geometric design and rapid production of complex structures.

Selective laser melting

SLM

additive manufacturing

production

3D printing technology

flexibility

design

complex structures


Input: Maraging steels have high strength and good ductility, and therefore have been widely used in aerospace and tooling sectors for many years.

Maraging steels

strength

ductility

aerospace

tooling


Input: This work aims to study the influence of aging temperature and aging time on the microstructure, mechanical property (hardness, strength and ductility) and tribological property of SLM maraging 18Ni-300 steel.

temperature

microstructure

mechanical property

tribological property

hardness

strength

ductility

SLM

maraging

steel


Input: The results reveal that the aging conditions had a significant impact on the strength and wear-resistance of the SLM maraging steel.

impact

strength

SLM

maraging steel


Input: The optimal aging conditions for the SLM maraging steel produced in this work were 490 °C for 3 h under which strength and wear-resistance were maximised.

SLM

maraging steel

strength


Input: Lower or higher aging temperature led to under-aging or over-aging phenomena, reducing the strength and wear-resistance performance.

temperature

led

strength

performance


Input: Shorter or longer aging time also resulted in the decrease of strength and wear-resistance performance of the SLM maraging steel as compared with the optimal conditions.

strength

performance

SLM

maraging steel

as


Input: The variation of the mechanical and tribological properties is primarily due to changes in phase compositions and microstructures of the SLM maraging steels.

variation

tribological properties

phase compositions

mechanical

microstructures

maraging steels

SLM


Input: The integration of novel additively manufactured (AM) materials and processes with traditional materials and manufacturing techniques, including the insertion of commercial off-the-shelf (COTS) components such as resistors, switches, batteries and light emitting diodes (LEDs), has led to the development of increasingly complex ‘hybrid’ electronics including: antennas, waveguides, radio frequency identification (RFID) tags, various sensors, circuits and devices.

additively manufactured

AM

manufacturing

materials

processes

materials

electronics

radio frequency

components

sensors

as

light emitting diodes

LEDs

led


Input: Here we examine the resiliency and radio frequency (RF) performance of two commercially available conductive inks (DuPont CB028 and KA801) printed onto a radar transparent substrate (poly ether, ether ketone; PEEK).

radio frequency

performance

transparent

substrate

PEEK


Input: The quality of ink adhesion, a factor found to directly correlate with antenna performance, is examined via adhesion testing after exposure to high accelerations up to 20,000 g and temperature cycling from −54 °C to +71 °C.

quality

performance

exposure

ink

adhesion

adhesion

temperature


Input: Overall, the designs, procedures and results provide a framework for multi-materials resiliency assessment as well as aspects unique to materials resiliency under harsh environmental conditions.

designs

framework

materials

as

as


Input: Lattice structures have been intensively researched for their light-weight properties and unique functions in specific applications such as for impact protection and biomedical-implant.

Lattice structures

light-weight

as

impact


Input: The advancement of additive manufacturing simplifies the fabrication of lattice structures as opposed to conventional manufacturing and this opens doors to create more designs.

additive manufacturing

fabrication

conventional manufacturing

lattice structures

designs

as


Input: There are ample research opportunities to explore the mechanical performance of the lattice structures fabricated by this technology specific to each design.

research

fabricated

technology

mechanical

lattice structures

design


Input: This study filled the research gap by investigating the deformation behaviour and compressive properties of Ti-6Al-4V lattice structures fabricated by a powder bed fusion method from the aspects of design, orientation and density.

research

deformation

properties

fabricated

orientation

lattice structures

design

powder bed fusion

density


Input: The results were compared between cubic and honeycomb unit designs, between two orientations and across five different densities.

honeycomb

orientations

designs


Input: Results showed that both cubic and honeycomb lattice deformed in a layer-by-layer manner for the first tested orientation, where vertical struts were parallel to the compression direction.

honeycomb

layer-by-layer

orientation

vertical

deformed

struts

compression


Input: In the second tested orientation, where lattice struts were angled with respect to the direction of compression, the deformation behaviour was observed as a single diagonal shear band.

orientation

lattice

deformation

compression

as


Input: As the density of the structure increased, the deformation pattern shifted towards diagonal crack similar to a solid part.

As

density

structure

deformation


Input: Honeycomb lattice structure had the highest density efficiency for energy absorption in both orientations and for first maximum compressive strength in the second orientation.

Honeycomb

structure

orientations

orientation

density

compressive strength

energy absorption


Input: Change of orientation significantly affected the efficiency in plateau stress for cubic lattice structure, and compressive property values for honeycomb lattice structure.

orientation

property

honeycomb

structure

stress

lattice structure


Input: Comparative studies showed that the first maximum compressive strength and energy absorption of the lattice structures in the first orientation were higher than most of the lattice designs from other literature.

compressive strength

energy absorption

lattice structures

lattice designs

orientation


Input: This paper describes a facile method to fabricate complex three-dimensional (3D) antennas by vacuum filling gallium-based liquid metals into 3D printed cavities at room temperature.

fabricate

3D printed

three-dimensional

liquid metals

temperature


Input: To create the cavities, a commercial printer co-prints a sacrificial wax-like material with an acrylic resin.

printer

material

acrylic


Input: Dissolving the printed wax in oil creates cavities as small as 500 μm within the acrylic monolith.

wax

oil

as

as

acrylic


Input: Placing the entire structure under vacuum evacuates most of the air from these cavities through a reservoir of liquid metal that covers a single inlet.

structure

liquid metal

inlet


Input: Returning the assembly to atmospheric pressure pushes the metal from the reservoir into the cavities due to the pressure differential.

assembly

pressure

pressure

metal


Input: This method enables filling of the closed internal cavities to create planar and curved conductive 3D geometries without leaving pockets of trapped air that lead to defects.

3D geometries

lead

defects


Input: An advantage of this technique is the ability to rapidly prototype 3D embedded antennas and other microwave components with metallic conductivity at room temperature using a simple process.

prototype 3D

process

microwave

components

metallic

conductivity

temperature

simple


Input: Because the conductors are liquid, they also enable the possibility of manipulating the properties of such devices by flowing metal in or out of selected cavities.

conductors

metal

properties


Input: The measured electrical properties of fabricated devices match well to electromagnetic simulations, indicating that the approach described here forms antenna geometries with high fidelity.

electrical properties

fabricated

geometries

simulations


Input: Residual stresses and distortion in Additive Manufactured (AM) parts are two key obstacles which seriously hinder the wide application of this technology.

Residual stresses

distortion

technology

Additive Manufactured

AM


Input: Nowadays, understanding the thermomechanical behavior induced by the AM process is still a complex task which must take into account the effects of both the process and the material parameters, the microstructure evolution as well as the pre-heating strategy.

thermomechanical

process

microstructure evolution

AM process

material

as

as


Input: One of the challenges of this work is to increase the complexity of the geometries used to study the thermomechanical behavior induced by the AM process.

complexity

geometries

thermomechanical

AM process


Input: The samples have been fabricated by Directed Energy Deposition (DED).

samples

fabricated

Directed Energy Deposition

DED


Input: In-situ thermal and distortion histories of the substrate are measured in order to calibrate the 3D coupled thermo-mechanical model.

In-situ

distortion

thermo-mechanical model

substrate


Input: Once the numerical results showed a good agreement with the temperature measurements, the validated model has been used to predict the residual stresses and distortions.

temperature

model

residual stresses


Input: Different process parameters have been analyzed to study their sensitivity to the process assessment.

process parameters

process

sensitivity


Input: Different preheating strategies have been also analyzed to check their effectiveness on the mitigation of both distortions and residual stresses.

preheating

effectiveness

residual stresses


Input: Finally, some simplifications of the actual scanning sequence are proposed to reduce the computational cost without loss of the accuracy of the simulation framework.

scanning

framework

accuracy

simulation


Input: Laser-Powder Bed Fusion (L-PBF), an additive manufacturing process, produces a distinctive microstructure that closely resembles the weld metal microstructure but at a much finer scale.

Bed Fusion

L-PBF

additive manufacturing process

microstructure

microstructure

weld metal


Input: The solidification parameters, particularly temperature gradient and solidification rate, are important to study the as-built microstructure.

solidification parameters

microstructure

temperature gradient

solidification rate


Input: In the present study, a computational framework with meso-scale resolution is developed for L-PBF of Inconel® 718 (IN718), a Ni-base superalloy.

framework

resolution

L-PBF


Input: The framework combines a powder packing model based on Discrete Element Method and a 3-D transient heat and fluid flow simulation.

framework

model

Discrete Element Method

heat

powder

fluid flow


Input: The latter, i.e., the molten pool model, captures the interaction between laser beam and individual powder particles including free surface evolution, surface tension and evaporation.

molten pool

model

laser beam

free surface

evolution

evaporation

powder particles

surface tension


Input: The solidification parameters, calculated from the temperature fields, are used to assess the solidification morphology and grain size using existing theoretical models.

solidification parameters

solidification morphology

theoretical models

temperature

grain size


Input: The IN718 coupon built by L-PBF are characterized using optical and scanning electron microscopies.

L-PBF

optical

scanning electron microscopies


Input: The experimental data of molten pool size and solidification microstructure are compared to the corresponding simulation results.

experimental data

molten pool

solidification microstructure

simulation


Input: Selective laser sintering, also called laser sintering (LS), is an additive manufacturing process that requires micronized plastic powder.

Selective laser sintering

laser sintering

additive manufacturing process

plastic


Input: Recently, we showed poly (ethylene terephthalate (PET) powder is a suitable material for LS, with a comparable printing performance as the current front-runner, polyamide 12 (PA12).

powder

material

as

polyamide 12

printing performance


Input: However, the LS process, by its nature, leaves unused powder that has been exposed to heat for prolonged time, and this powder may not be fully re-usable due to degradation.In this work, the re-use potential of heat-exposed PET powder is established.

process

heat

powder

powder

be

powder


Input: This is a matter of crucial importance as powders suitable for LS are very expensive, and the powder left after a building episode has to be re-used.

as

powder

be


Input: Heat-exposed PA12 has to be blended or refreshed with virgin powder, to avoid printing defects.

be

virgin powder

defects


Input: In contrast, heat-exposed PET powder, after 96 h at 210 °C, could be used, without refreshing with a portion of virgin powder.

powder

be

virgin powder


Input: The printed articles from heat-exposed powders were as good as those from the fresh powder.

powders

as

as

powder


Input: There was no cross-linking and there was only a minor increase in the molecular weight of the powder after 96 h, at 210 °C.

cross-linking

weight

powder


Input: Electron Beam Melting (EBM) is an increasingly used Additive Manufacturing (AM) technique employed by many industrial sectors, including the medical device and aerospace industries.

Electron Beam Melting

EBM

Additive Manufacturing

AM

industrial sectors

medical device

aerospace industries


Input: The application of this technology is, however, challenged by the lack of process monitoring and control system that underpins process repeatability and part quality reproducibility.

technology

process monitoring

process

quality

control system


Input: An electronic imaging system prototype has been developed to serve as an EBM monitoring equipment, the capabilities of which have been verified at room temperature and at 320 ± 10 °C.

imaging

prototype

as

EBM

equipment

temperature


Input: Nevertheless, in order to fully assess the applicability of this technique, electronic imaging needs to be conducted at a range of elevated temperatures to fully understand the influence of temperature on electronic image quality.

imaging

be

range

temperatures

temperature

image


Input: Building on top of the previous electronic imaging trials at room temperature, this paper disseminates the essential step changes to allow high temperature electronic imaging: (1) modification of a signal amplifier to deal with high electron beam current during electron beam heating, and (2) design of an open-source electron beam heating algorithm to maximise flexibility for user-defined heating strategy.

imaging

imaging

temperature

temperature

step

electron beam

electron beam heating

open-source

electron beam heating

algorithm

design

flexibility

heating


Input: In this paper, electronic imaging pilot trials at elevated temperatures, ranging from room temperature to 650°C, were carried out.

imaging

temperatures

temperature


Input: Image quality measure Q of the digital electron images was evaluated, and the influence of temperature was investigated.

Image

images

temperature


Input: In this study, raw electronic images generated at higher temperatures had greater Q values, i.e.

images

temperatures


Input: better global image quality.

image


Input: It has been demonstrated that, for temperatures between 30°C-650°C, the influence of temperature on electronic image quality was not adversely affecting the visual clarity of image features.

temperatures

temperature

image

image


Input: It is thus envisaged that the prototype has a potential to contribute to in-process EBM monitoring, and this paper has served as a crucial precursor to the ultimate goal of carrying out electronic imaging under real EBM building condition.

prototype

EBM

EBM

as

precursor

imaging


Input: Local microstructure control in electron beam powder bed fusion (EB-PBF) is of great interest to the additive manufacturing community to realize complex part geometry with targeted performance.

microstructure

electron beam

geometry

performance

bed fusion

additive manufacturing


Input: The local microstructure control relies on having a detailed understanding of local melt pool physics (e.g., 3-D melt pool shape as well as spatial and temporal variations of thermal gradient (G) and solidification rate (R)).

microstructure

variations

melt pool

as

as

thermal gradient

solidification rate


Input: In this research, a new scan strategy referred to as ghost beam is numerically evaluated as a candidate to achieve the targeted G and R of IN718 alloy.

research

as

as

IN718 alloy

beam


Input: The boundary conditions for simulations, including the speed (490 mm/s) and spatial locations of the beam within a given layer, are obtained by using series of snapshot images, recorded at 12,000 frames per second, using a high-speed camera.

boundary conditions

images

simulations

beam

camera

layer


Input: The heat transfer simulations were performed using TRUCHAS an open-source software deployed within a high-performance computational infrastructure.

heat transfer

open-source


Input: The simulation results showed that reheating at short beam on-time and time delay decreases both G and R. Local variation of R at the center of the melt pool trailing edge showed periodic temporal fluctuations.

simulation

beam

variation

melt pool


Input: This paper introduces continuous lattice fabrication (CLF)–a novel additive manufacturing (AM) technique invented for fiber-reinforced thermoplastic composites–and demonstrates its ability to exploit anisotropic material properties in digitally fabricated structures.

lattice

fabricated

fabrication

additive manufacturing

AM

thermoplastic composites

anisotropic material properties


Input: In contrast to the layer-by-layer approaches employed in most AM processes, CLF enables the directed orientation of the fibers in all spatial coordinates, that is in the x-, y-, and z-directions.

layer-by-layer

orientation

AM processes

fibers

coordinates


Input: Based on a serial pultrusion and extrusion approach, CLF consolidates commingled yarns in situ and allows for the continuous deposition of high fiber volume fraction (> 50%) materials along a programmable trajectory without the use of molds or sacrificial layers by exploiting the high viscosities of fiber-filled polymer melts.

pultrusion

extrusion

in situ

deposition

fraction

materials

fiber

polymer melts

molds


Input: The capacity of CLF to produce high-performance structural components is demonstrated in the fabrication of an ultra-lightweight load-bearing lattice structure with outstanding stiffness-to-density and strength-to-density performance (compression modulus of 13.23 MPa and compressive strength of 0.20 MPa at a core density of 9 mg/cm3).

capacity

structural components

performance

MPa

MPa

fabrication

load-bearing

lattice structure

compression

compressive strength

core


Input: This digital fabrication method enables new approaches in load-tailored design, including the possibility to build freeform structures, which have previously been overlooked due to difficulties and limitations in modern fiber composite manufacturing capabilities.

digital fabrication

design

build

fiber composite


Input: Additive Manufacturing provides many advantages in reduced lead times and increased geometric freedom compared to traditional manufacturing methods, but material properties are often reduced.

Additive Manufacturing

traditional manufacturing

lead times

geometric freedom

material properties


Input: This paper considers powder bed fusion of polyamide 12 (PA12, Nylon 12) produced by three different processes: laser sintering (LS), multijet fusion (MJF) /high speed sintering (HSS), and large area projection sintering (LAPS).

powder bed fusion

laser sintering

MJF

sintering

sintering

polyamide 12

Nylon

HSS

processes

fusion

LAPS

area


Input: While all utilize similar PA12 materials, they are found to differ significantly in mechanical properties especially in elongation to break.

materials

mechanical properties

elongation


Input: The slower heating methods (MJF/HSS and LAPS) produce large elongation at break with the LAPS process showing 10x elongation and MJF/HSS exhibiting 2.5x the elongation when compared to commercial LS samples.

heating

LAPS

LAPS

samples

elongation

elongation

elongation


Input: While there are small differences in crystallinity between these samples, the difference may be attributed to changes in the heating and cooling rates of the LAPS samples.

samples

LAPS

be

heating

cooling rates


Input: The maximum inlet velocity of the filament is determined according to the process parameters.

inlet

filament

process parameters


Input: The velocity field, shear rate and viscosity in the nozzle were determined by analytical study and numerical simulation.

viscosity

nozzle

numerical simulation


Input: The extrudate shape agrees with the numerical simulation: the extrudate undergoes severe deformation at high shear rate.

extrudate

extrudate

numerical simulation

deformation


Input: Fused filament fabrication (FFF) is one of the various types of additive manufacturing processes.

Fused filament fabrication

FFF

additive manufacturing processes


Input: Similar to other types, FFF enables free-form fabrication and optimised structures by using polymeric filaments as the raw material.

FFF

fabrication

filaments

as

raw material


Input: This work aims to optimise the printing conditions of the FFF process based on reliable properties, such as printing parameters and physical properties of polymers.

FFF

properties

parameters

as

polymers

physical properties


Input: The selected polymer is poly (lactic) acid (PLA), which is a biodegradable thermoplastic polyester derived from corn starch and is one of the most common polymers in the FFF process.

polymer

PLA

thermoplastic

polyester

polymers

starch

FFF