Input: Firstly, the maximum inlet velocity of the filament in the liquefier was empirically determined according to process parameters, such as feed rate, nozzle diameter and dimensions of the deposited segment.

inlet

filament

as

process parameters

nozzle diameter

dimensions


Input: Secondly, the rheological behaviour of the PLA, including the velocity field, shear rate and viscosity distribution in the nozzle, was determined via analytical study and numerical simulation.

rheological

viscosity

PLA

distribution

nozzle

numerical simulation


Input: Our results indicated the variation in the shear rate according to the diameter of the nozzle and the inlet velocity.

variation

diameter

nozzle

inlet


Input: Finally, the distribution of the viscosity along the radius of the nozzle was obtained.

distribution

viscosity

nozzle


Input: At high inlet velocity, several defects appeared at the surface of the extrudates.

inlet

defects

surface


Input: The defects predicted via numerical simulation were reasonably consistent with that observed from an optical microscope.

defects

numerical simulation

optical

microscope


Input: nozzle diameter, feed rate and layer height) to improve the quality of the manufactured parts.

nozzle diameter

quality

manufactured

feed

layer height


Input: Optimized LPBF gives AA7075 parts with density 99.5%, but containing hot cracks.

LPBF

density


Input: Preventing cracking requires optimization of chemical composition of the powder.

cracking

optimization

chemical composition

powder


Input: High isostatic pressing is not effective in healing long cracks.

isostatic pressing


Input: Solidification cracks are formed by the liquid film rupture mode.

Solidification cracks


Input: Silicon impurity appears to significantly increase stability of the liquid film.

Silicon

impurity

stability


Input: Laser powder bed fusion (LPBF) is an attractive technology of manufacturing highstrength aluminium alloy parts for the aircraft and automobile industries, limited by poor processability of these alloys.

Laser powder bed fusion

LPBF

manufacturing

technology

aluminium alloy

alloys

automobile


Input: This work was aimed at finding the process window for the LPBF manufacturing of defect-free components of AA7075 alloy.

process

LPBF

components

alloy


Input: Optimization of the parameters was performed at each stage of the multi-stage research, i.e.

Optimization

parameters

research


Input: At each stage, the relation between LPBF parameters and defect formation with a focus on hot cracking was investigated and discussed.

LPBF

defect

hot cracking


Input: Due to the optimization of process parameters, the density of volumetric specimens above 99% was reached and vaporization losses of the alloying elements were significantly reduced, but solidification cracks could not be eliminated.

optimization

process parameters

density

alloying elements

be

solidification cracks


Input: It was found that solidification cracks were formed by the liquid film rupture mode, mainly along columnar grain boundaries.

solidification cracks

columnar grain boundaries


Input: The EDS microanalysis showed intergranular microsegregation, not only of the main alloying elements (Zn, Mg, Cu) but also of minor elements such as Si.

EDS

microsegregation

alloying elements

Zn

Mg

Cu

elements

as


Input: Silicon may play a significant role in increasing susceptibility to cracking by increasing the stability of the liquid film.

Silicon

susceptibility

stability

cracking


Input: Reduction in the silicon impurity content in the AA7075 powder gives a chance to reduce susceptibility to cracking with no change of the alloy specification.

Reduction

cracking

silicon

powder

alloy

impurity

susceptibility


Input: 316L steel powder reuse (several times) in SLM leads to the increase of δ-ferrite.

steel powder

SLM


Input: Magnetic attractive interaction among δ-ferrite powder particles is noticed.

powder particles


Input: Particle clustering causes poor packing and non-uniformities in the powder layer.

Particle

powder

layer


Input: Defect formation is more critical when the pin support structure is used.

Defect

support structure


Input: Magnetic separation allows separation of austenite and δ-ferrite powder fractions.

Magnetic separation

austenite

powder


Input: The presence of δ-ferrite in 316L stainless steel powder reused several times contributes to structural defect formation in selective laser melted parts built using the pin support structure.

316L stainless steel powder

structural defect

selective laser melted

support structure


Input: The virgin 316L stainless steel powder is fully austenitic.

316L stainless steel powder

austenitic


Input: After several powder reuse cycles, reused powder has a finer particle size and about 6 vol.

powder

powder

particle


Input: Phase change occurs due to the thermal cycles imposed on the particles near the melt pool, via spattering and further interaction of in-flight droplets with the laser beam.

Phase

particles

droplets

laser beam

thermal cycles

melt pool


Input: Phase transformation changes the magnetic behavior of the powder leading to particle clustering in the powder bed.

Phase

particle

powder

powder bed


Input: The uniformity of the powder bed is affected causing defects such as porosity, delamination, warping and lack of fusion.

powder bed

defects

delamination

warping

fusion

as


Input: These defects are more prone to occur at the beginning of the building process.

defects

building process


Input: The magnetic and non-magnetic fractions of the reused powder were separated from each other using magnetic separation.

powder

magnetic separation


Input: Powder characterization was performed using scanning electron microscopy, laser scattering particle size analysis, X-ray diffraction, and magnetization measurements.

Powder

scanning electron microscopy

X-ray diffraction

laser

particle


Input: An explanation for the formation of such defects based on the magnetic behavior of δ-ferrite powder particles is proposed.

defects

powder particles


Input: The results suggest that magnetic separation should be used to remove magnetic particles after several reuse cycles.

magnetic separation

particles

be


Input: In the context of additive manufacturing, we illustrate how computational multi-body dynamics (CMBD) analysis can (a) increase printing throughput; and, (b) play a role in improving the quality of 3D printed parts.

additive manufacturing

throughput

b

quality

3D printed parts


Input: Throughput is increased by packing the printing volume with as many parts as possible.

Throughput

volume

as

as


Input: The problem becomes one of determining where each component that needs to be printed finds itself inside the printing volume.

component

be

volume


Input: Finding the position and orientation of each part is accomplished through CMBD analysis, a point illustrated through an example in which an open-source dynamics engine called Chrono is used to simulate the filling of the active printing volume with a dress that is subsequently 3D printed.

orientation

open-source

volume

3D printed


Input: In relation to (b), we use million-body dynamics simulations to gauge how various granular mixture parameters and rolling regimes combine to ultimately control the roughness of the surface being sintered.

b

simulations

parameters

surface

rolling

sintered

roughness


Input: The quality assessment of AM materials containing defects is a complex topic.

quality

defects

AM materials


Input: Multiple defect types were characterised by X-ray CT and metallographic analysis.

defect

X-ray CT


Input: The critical defects in fatigue samples were compared to the statistical estimates.

defects

fatigue


Input: Quality correctly assessed by both methods for material obtained by three processes.

Quality

processes

material


Input: Better precision and lower cost by CT when similar volumes are investigated.

precision

CT


Input: While the adoption of metal additive manufacturing (AM) is growing exponentially owing to its wide range of potential applications, its application to safety-critical and structural parts is significantly impeded by the lack of standards.

metal additive manufacturing

AM

range

standards


Input: Quality assessment of AM products is a crucial requirement, as the AM process induces internal defects that can have detrimental effects on the fatigue resistance.By evaluating the defect distribution, it is possible to perform a fracture mechanics assessment to estimate the fatigue strength and service lifetime of AM materials.

Quality

defects

defect

fracture

AM

AM process

as

AM materials

fatigue

fatigue strength


Input: This strategy has been successfully applied to selective laser-melted AlSi10Mg by performing X-ray micro-computed tomography (μCT) and applying suitable statistical methods (i.e., statistics of extremes).

X-ray micro-computed tomography

statistical methods

statistics


Input: The results showed that both techniques were able to pinpoint a significant difference in the prospective largest defect in a material volume corresponding to the gauge section of a specimen.

defect

material

gauge section


Input: However, extrapolation of the critical defect size for fatigue failure using PS data was less accurate and less conservative than that using CT data.

defect

failure

data

fatigue

accurate

CT


Input: Investigation of manufacturing continuous ﬁber reinforced thermoplastic polymer composites (CFRTPCs) through 3D printing technologies has attracted great attention in the past few years due to excellent properties of CFRTPCs, such as high strength-to-weight ratio and stiffness.

manufacturing

reinforced

properties

polymer composites

as

3D printing technologies

stiffness


Input: It is found that the properties of CFRTPCs are affected not only by the properties of the individual parent materials but also by interfacial characteristics.

properties

properties

materials


Input: Modification of the interface is a great method to improve the wettability between fiber and polymer and hence the mechanical properties of CFRTPCs.

interface

wettability

mechanical properties

fiber

polymer


Input: In this work, an ultrasound-assisted 3D printing device for CFRTPCs is developed.

3D printing


Input: The changes of surface profile and chemical structure of carbon fiber and carbon fiber prepreg after ultrasonic treatment are studied.

surface profile

structure

carbon fiber

carbon fiber


Input: The effects of ultrasonic processing parameters on the microstructure and mechanical properties of CFRTPCs are provided.

parameters

microstructure

mechanical properties


Input: It is found that the tensile and flexural strength of composite materials are improved by 34% and 29%, respectively, compared with untreated material by using the ultrasonic amplitude of 40 μm, resin solution mass fraction of 10%, processing speed of 15 mm/s.

tensile

flexural strength

composite materials

material

resin

fraction


Input: Direct osseous healing to prosthetic components is a prerequisite for the clinical success of uncemented treatment in total hip replacements (THR).

prosthetic

components

hip


Input: The demands imposed on the material properties are constantly being stepped up to withstand the impact of an active lifestyle and ensure lifelong integration.

material properties

impact


Input: Cobalt–chromium–molybdenum (Co-Cr-Mo) materials are interesting for their excellent mechanical stability, corrosion resistance and possibility to be produced by additive manufacturing into complex designs with modifiable stiffness.

materials

corrosion resistance

mechanical

be

additive manufacturing

designs

stiffness


Input: The bone response to Co-Cr-Mo is regarded as inferior to that of titanium and are usually cemented in THR.

bone

as

titanium


Input: The hypothesis in the present study was that a low amount of Zr in the Co-Cr-Mo alloy would improve the bone response and biomechanical anchorage.

Zr

alloy

bone

biomechanical


Input: The results showed significantly higher implant stability for the Co-Cr-Mo alloy with an addition of 0.04% Zr after eight weeks of healing in rabbits, while no major differences were observed in the amount of bone formed around the implants.

implant

implants

alloy

Zr

bone


Input: Further, bone tissue grew into surface irregularities and in direct contact with the implant surfaces.

bone

surface

contact

implant


Input: It is concluded that additively manufactured Co-Cr-Mo alloy implants osseointegrate and that the addition of a low amount of Zr to the bulk Co-Cr-Mo further improves the bone anchorage.

additively manufactured

alloy

Zr

bone


Input: Selective laser melting (SLM) is a widely used additive manufacturing method for building metal parts in a layer-by-layer manner thereby imposing almost no limitations on the geometrical layout of the part.

Selective laser melting

SLM

additive manufacturing

metal

layer-by-layer

layout


Input: The SLM process has a crucial impact on the microstructure, strength, surface quality and even the shape of the part, all of which depend on the thermal history of material points within the part.

SLM

process

impact

microstructure

strength

surface quality

material


Input: In this paper, we present a computationally tractable thermal model for the SLM process which accounts for individual laser scanning vectors.

model

process

SLM

laser


Input: First, a closed form solution of a line heat source is calculated to represent the laser scanning vectors in a semi-infinite space.

solution

heat source

laser


Input: The thermal boundary conditions are accounted for by a complimentary correction field, which is computed numerically.

boundary conditions


Input: The proposed semi-analytical model can be used to simulate manufacturing geometrically complex parts and allows spatial discretisation to be much coarser than the characteristic length scale of the process: laser spot size, except in the vicinity of boundaries.

model

process

be

be

manufacturing

length scale

laser spot size

boundaries


Input: The underlying assumption of linearity of the heat equation in the proposed model is justified by comparisons with a fully non-linear model and experiments.

linearity

heat

model

model


Input: The accuracy of the proposed boundary correction scheme is demonstrated by a dedicated numerical example on a simple cubic part.

accuracy

boundary

simple


Input: The influence of the part design and scanning strategy on the temperature transients are subsequently analysed on a geometrically complex part.

design

scanning strategy

temperature


Input: The results show that overhanging features of a part obstruct the heat flow towards the base-plate thereby creating local overheating which in turn decrease local cooling rate.

overhanging features

heat

cooling rate


Input: Finally, a real SLM process for a part with an overhanging feature is modelled for validation of the proposed model.

SLM

process

validation

model

overhanging feature


Input: Reasonable agreement between the model predictions and the experimentally measured values can be observed.

model

be


Input: The emergence of 4D printing has revolutionized the additive manufacturing industry by enabling dynamic shape memory effects ensured by the use of smart materials.

4D printing

additive manufacturing

dynamic

materials


Input: In addition to 3D fabrication, 4D printed products need to undergo shape programming and recovery cycles to achieve desired shape memory effects.

shape memory effects


Input: Due to the new process and material characteristics, energy consumption models established for 3D printing are no longer applicable for 4D printing.

process

material

3D printing

4D printing


Input: In current literature, the environmental sustainability for 4D printing has not yet been evaluated, leading to unknown environmental impacts that could be caused by 4D printing processes and/or materials.

sustainability

materials

4D printing

4D printing

be


Input: In this research, theoretical models for quantifying the energy consumption in 4D printing thermal-responsive polymers are established by jointly considering the compositional design for materials.

research

theoretical models

materials

4D printing

polymers

design


Input: Experiments and case studies are performed to validate the proposed models and further investigate some critical factors that can affect energy consumption, e.g., values of process parameters like layer thickness, and thermo-temporal conditions in shape memory cycles.

case studies

process parameters

critical factors

layer thickness


Input: The case study results show that overall energy consumption can be reduced by 1) increasing the concentrations of multi-functional crosslinkers in material composition, and 2) setting the shape programming and recovery temperatures as 10 to 15℃ above the material glass transition temperature without compromising the shape fixity and recovery ratios.

case study

composition

glass transition temperature

be

material

as

material

temperatures


Input: In addition, by adjusting the influential parameters throughout different stages in 4D printing, the total energy consumption can be reduced by 37.33%, which corresponds to a reduction of 259.52 pounds of CO2 emissions per kilogram methacrylate resin.

parameters

reduction

4D printing

be

resin


Input: While additive manufacturing (AM), commonly known as 3D printing, has been in existence commercially for ∼30 years, desktop 3D printers are a relatively new and rapidly growing market segment.

additive manufacturing

AM

3D printing

as

desktop 3D printers


Input: This research highlights differences amongst 45 desktop 3D printers and suggests a method by which to evaluate such differences.

research

desktop 3D printers


Input: For this, a standard part consisting of various geometric features was designed and printed using each system.

standard

designed


Input: An updated version of a previously developed quantitative ranking model was utilized to rate the build precision of each system as well as other features, including build volume, size, cost, weight, and layer resolution.

quantitative

model

build

build volume

weight

layer resolution

as

as


Input: In addition, the research team observed part aesthetics and quantified mechanical properties.

research

mechanical properties


Input: The criteria evaluated in this ranking model may be modified by each user, to extend this methodology to other desktop AM systems, including professional-grade machines.

model

methodology

be

AM

machines


Input: As expected, the comparisons demonstrated that each model had slightly different rankings as compared to the model presented in this paper, with some outliers.

As

as

model

model


Input: Additive manufacturing of ceramics has been actively investigated with the objective of fabricating complex structures that compete in terms of material performance with traditionally manufactured ceramics but with the benefit of increased geometric freedom.

Additive manufacturing

fabricating

ceramics

material

ceramics

complex structures

manufactured

geometric freedom


Input: More specifically, zirconia provides high fracture toughness and thermal stability.

zirconia

fracture

thermal stability


Input: In addition, its dielectric permittivity may be the highest among materials available for 3D printing, and may enable the next generation of complex electromagnetic structures.

dielectric

be

materials

3D printing


Input: NanoParticle Jetting™ is a new material jetting process for selectively depositing nanoparticles and is capable of printing zirconia.

material jetting

nanoparticles

zirconia


Input: Dense, fine-featured parts can be manufactured with layer thicknesses as small as 10 μm and jetting resolution of 20 μm after a final sintering step.

be

as

as

layer thicknesses

jetting

sintering


Input: For this study, 3D printed zirconia using NanoParticle Jetting™ was characterized in terms of chemistry, density, crystallography, sintering shrinkage and dielectric properties as a foundation for developing high performance radio frequency (RF) components.

3D printed

crystallography

sintering

chemistry

shrinkage

performance

density

dielectric

components

as


Input: The experimental results indicate a yttria-stabilized ZrO2 structure exhibiting a bulk relative permittivity of 23 and a loss tangent of 0.0013 at microwave frequencies.

experimental

structure

microwave


Input: A simple zirconia dielectric resonator antenna is measured, confirming the measured dielectric properties and illustrating a practical application of this material.

simple

dielectric

dielectric

material


Input: The corrosion behavior of AISI316L AM parts is evaluated before and after the heat treatment then compared with the wrought samples.

corrosion behavior

AM parts

heat treatment

wrought samples


Input: AM parts have a better corrosion behavior compared to the wrought ones due to the absence of non-equilibrium phases.

AM parts

corrosion behavior

wrought


Input: The annealed AM sample has an improved corrosion behavior due to the decreasing of the residual stress level.

AM

corrosion behavior

residual stress


Input: The noticeable change in corrosion resistance for the wrought sample is a result of phase transformation.

corrosion resistance

wrought sample

phase


Input: This paper presents the investigation of the corrosion behavior of AISI316L samples prepared by laser-based powder bed fusion additive manufacturing (AM) method.

corrosion behavior

samples

powder bed fusion additive manufacturing

AM


Input: Both AM and conventional stainless steel 316L samples were examined in NaCl 3.5% solution before and after the annealing process using Tafel curves, Electrochemical Impedance Spectroscopy, and X-ray diffraction.

AM

annealing

stainless steel

NaCl

samples

solution

Electrochemical

Spectroscopy

X-ray diffraction


Input: The results indicate that the AM parts have an improved corrosion behavior than the conventional wrought samples.

AM parts

corrosion behavior

wrought samples


Input: Besides, the heat treatment process is found to further decrease the corrosion rate of the AM parts through the relieving of the residual stress.

heat treatment

corrosion

AM parts

residual stress


Input: In contrast, the post annealing induced improvement to corrosion resistance for the wrought samples is due to the elimination of martensite phase which almost always exists after the plastic deformation during their production process.

annealing

production

corrosion resistance

wrought samples

process

martensite

plastic deformation


Input: The IN718 sample with deposition rate of 2.2 kg/h and height 75 mm was prepared.

deposition rate

mm


Input: δ, γ'' and γ' phase are precipitated in bottom and middle region due to thermal cycle.

phase

thermal cycle


Input: The microhardness and room temperature tensile properties exhibit a high value.

microhardness

properties

temperature


Input: In order to meet the requirements for rapid manufacturing of large-scale high-performance metal components, the unique advantages of high-deposition-rate laser directed energy deposition (HDR-LDED, deposition rate ≥ 1 kg/h) technology have been attracted great attention.

rapid manufacturing

laser directed energy deposition

metal

components

deposition rate

technology


Input: HDR-LDED technology significantly improves the efficiency by simultaneously increasing the mass and energy input on basis of conventional laser directed energy deposition (C-LDED, deposition rate ≤ 0.3 kg/h), which dramatically changes the solidification condition and thermal cycling effect compared to C-LDED processes.

technology

solidification

processes

laser directed energy deposition

deposition rate

thermal cycling


Input: Based on this, Inconel 718 bulk samples were fabricated with a deposition rate of 2.2 kg/h and a height of 75 mm.

Inconel 718

samples

fabricated

deposition rate

mm


Input: Through experimental observation combined with finite element simulation, the precipitation morphology, thermal cycling effect and tensile properties at room temperature of the block samples at heights of 6 mm (bottom region), 37 mm (middle region) and 69 mm (top region) from the substrate were investigated.

experimental

finite element

precipitation morphology

samples

thermal cycling

temperature

tensile properties

mm

mm

mm

substrate


Input: The results show that both temperature interval and incubation time satisfy the precipitation conditions of the second phases because of the intense thermal cycling effect so that δ, γ'' and γ' phase are precipitated in the bottom and middle region of the as-deposited sample during the HDR-LDED process.

temperature

thermal cycling

precipitation

phase

sample

process


Input: As a result, the micro-hardness and the yield strength of the bottom region (385 HV; 745.1 ± 5.2 MPa) are similar to those of the middle region (381 HV; 752.2 ± 12.1 MPa), respectively.

As

yield strength

MPa

MPa


Input: The tensile fracture mechanism is shown in both fracture and debonding of the Laves phase.

tensile

fracture

fracture

Laves phase


Input: The inhomogeneous microstructures and corresponding mechanical property differences of Inconel 718 fabricated by HDR-LDED along the deposition direction suggest the necessity to conduct further research of the post heat treatment in the future.

microstructures

Inconel 718

mechanical property

fabricated

research

deposition direction

heat treatment


Input: We demonstrate that a low dielectric constant composite filament, useful for FFF printing, can be manufactured by combining a base thermoplastic polymer with hollow microspheres and a plasticizer.

dielectric

composite

be

thermoplastic polymer

plasticizer

FFF

microspheres


Input: Experimental results are provided for filaments made from two different base polymers (i.e.

Experimental

filaments

polymers


Input: ABS and HDPE) and varying volume fractions of hollow microspheres.

ABS

HDPE

volume fractions

microspheres


Input: We also describe an effective media model to predict the dielectric properties of the composite filaments as a function of the properties of the constituent materials (e.g.

model

properties

materials

dielectric

composite

as


Input: base polymer, hollow microspheres) and their relative volume fractions within the composite filament.

polymer

composite

microspheres

volume fractions


Input: Experimental test samples were printed using the new low-K filaments and experimental characterization results are provided that validate this approach.

Experimental

samples

experimental

filaments


Input: Proven real-time measurement capability of an in-house interferometry for both exposure cured height and dark cured height in photopolymer AM.

measurement

interferometry

exposure cured

cured

AM

photopolymer


Input: Demonstrated real-time closed-loop control of cured height in photopolymer AM with the interferometry and an empirical dark curing model.

closed-loop control

cured

AM

curing

photopolymer

interferometry

empirical


Input: Thorough error analysis for future research on improving the process control.

error

research

process control


Input: An exemplary study on a lab-scale parallel computing enabled cyber-physical system for AM process sensing, modeling and control.

AM process

modeling


Input: Exposure Controlled Projection Lithography (ECPL) is an in-house additive manufacturing process that can cure microscale photopolymer parts on a stationary transparent substrate with a time sequence of patterned ultraviolet beams delivered from underneath.

Exposure

Lithography

cure

transparent

ultraviolet

additive manufacturing process

photopolymer

substrate


Input: An in-situ interferometric curing monitoring and measurement (ICM & M) system has been developed to measure the ECPL process output of cured height profile.

in-situ

process

curing

cured

measurement

profile


Input: This study develops a real-time feedback control system that utilizes an empirical process model and an online ICM & M feedback to automatically and accurately cure a part with targeted height.

feedback

feedback

control system

empirical

model

accurately


Input: Due to the nature of photopolymerization, the total height of an ECPL cured part is divided into exposure cured height and dark cured height.

photopolymerization

cured

cured

exposure cured


Input: The exposure cured height is controlled by a closed-loop feedback on-off controller.

exposure cured

feedback

controller


Input: The dark cured height is compensated by an empirical process model obtained from the ICM & M measurements for a series of cured parts.

cured

cured

empirical

model


Input: A parallel computing software application is developed to implement the real-time measurement and control simultaneously.

software

measurement


Input: The experimental results directly validate the ICM & M system’ s real-time capability in capturing the process dynamics and in sensing the process output.

experimental

process

process

s

sensing


Input: Meanwhile, it evidently demonstrates the feedback control system’ s satisfactory performance in achieving the setpoint of total height, despite the presence of ECPL process uncertainties, ICM & M noises and computing interruptions.

feedback

control system

s

performance

process


Input: Generally, the study establishes a paradigm of improving additive manufacturing with a real-time closed-loop measurement and control system.

additive manufacturing

measurement

control system


Input: Recent advances in additive manufacturing facilitated the fabrication of parts with great geometrical complexity and relatively small size, and allowed for the fabrication of topologies that could not have been achieved using traditional fabrication techniques.

additive manufacturing

fabrication

fabrication

fabrication

geometrical complexity

topologies


Input: In this work, we explore the topology-property relationship of several classes of periodic cellular materials; the first class is strut-based structures, while the second and third classes are derived from the mathematically created triply periodic minimal surfaces, namely; the skeletal-TPMS and sheet-TPMS cellular structures.

cellular materials

strut-based

cellular structures

triply periodic minimal surfaces


Input: Powder bed fusion technology was employed to fabricate the cellular structures of various relative densities out of Maraging steel.

Powder bed fusion

fabricate

cellular structures

relative densities

Maraging steel


Input: Scanning electron microscope (SEM) was also employed to assess the quality of the printed parts.

Scanning electron microscope

SEM

quality


Input: Compressive testing was performed to deduce the mechanical properties of the considered cellular structures.

testing

mechanical properties

cellular structures


Input: Results showed that the sheet-TPMS based cellular structures exhibited a near stretching-dominated deformation behavior, while skeletal-TPMS showed a bending-dominated behavior.

cellular structures

deformation


Input: Overall the sheet-TPMS based cellular structures showed superior mechanical properties among all the tested structures.

cellular structures

mechanical properties


Input: The most interesting observation is that sheet-based Diamond TPMS structure showed the best mechanical performance with nearly independence of relative density.

Diamond

structure

mechanical

relative density


Input: It was also observed that at decreased volume fractions the effect of geometry on the mechanical properties is more pronounced.

volume fractions

geometry

mechanical properties


Input: Polyhydroxyalkanoate (PHA) composites containing siliceous sponge spicules (SSS) were prepared from three-dimensional (3D) printing filaments.

composites

filaments

three-dimensional


Input: Mechanical and morphological characterizations indicated that the improved adhesion between the SSS and PHA-g-AA enhanced the tensile strength at failure and Young’ s modulus of the composite compared with that of PHA/SSS.

Mechanical

morphological characterizations

adhesion

tensile strength

failure

s

composite


Input: The PHA-g-AA/SSS composites were also more water-resistant than the PHA/SSS composites.

composites

composites


Input: Human foreskin fibroblasts (FBs) were seeded on two series of these composites to assess cytocompatibility.

fibroblasts

composites


Input: FB proliferation was greater for the PHA/SSS composites than the PHA-g-AA/SSS composites.

composites

composites


Input: Moreover, SSS enhanced the antioxidant, anti-inflammatory and antibacterial properties of PHA-g-AA/SSS and PHA/SSS composites, demonstrating the potential of PHA-g-AA/SSS and PHA/SSS composites for biomedical material applications.

properties

composites

composites

biomedical


Input: Refined microstructure of AlSi10Mg alloy by electron beam melting (EBM) technology.

microstructure

technology

AlSi10Mg alloy

electron beam melting

EBM


Input: As-EBM-built AlSi10Mg alloy contains fine granular Si phase and bimodal Al grains.

AlSi10Mg alloy

Si

Al

phase


Input: As-EBM-built AlSi10Mg alloy is strengthened by the nano-Si precipitates.

AlSi10Mg alloy

precipitates


Input: Refining the microstructure to improve the ductility of an Al‒Si alloy is challenging.

microstructure

ductility

alloy


Input: In this paper, we report for the first time a novel microstructure refinement approach for AlSi10Mg (wt%) alloys using electron beam melting (EBM) technology, without the addition of any modification elements.

microstructure

technology

alloys

elements

electron beam melting

EBM


Input: The synergetic effect of superheating, fast cooling, and preheating contributes to a refined Si phase with a fine granular structure (0.5–2 μm) within bimodal Al grains (40 μm grains and 0.5–2 μm sub-grains).

cooling

preheating

Si

Al

phase

structure

grains


Input: A maximum ductility of approximately 32.7% with a tensile strength of approximately 136 MPa was achieved for the as-built AlSi10Mg EBM alloy.

ductility

tensile strength

MPa

alloy


Input: After solution heat treatment and T6-like aging, nano-Si precipitates formed which strengthened the alloys.

solution heat treatment

precipitates

alloys


Input: The pathway developed in this study for refining the Al–Si alloy microstructure to improve the tensile ductility will provide a feasible and fast manufacturing method for improving the microstructure and mechanical properties of other low-melting temperature alloys in the near future using EBM technology.

alloy

alloys

tensile ductility

manufacturing

EBM

microstructure

mechanical properties

temperature


Input: Lunar regolith simulant is used as feedstock in the dry aerosol deposition process.

as

deposition process


Input: Dry aerosol deposition builds thick films on steel, glass and polyimide substrates.

deposition

builds

steel

glass


Input: Mineral mixture is transformed directly to fully dense, nano-grained ceramic film.

fully dense

ceramic


Input: Phase and chemical composition of ceramic films are uniform and homogeneous.

Phase

chemical composition

homogeneous

ceramic


Input: Small change in composition occurs from powder to coating in aerosol deposition.

composition

deposition

powder

coating


Input: Dry Aerosol Deposition (DAD) is a ceramic coating process with the ability to build films and low profile 3D structures layer by layer and is therefore a promising additive manufacturing technique.

Deposition

3D structures

ceramic coating

build

layer

profile

additive manufacturing


Input: DAD is unique because it uses kinetic energy rather than thermal energy for densification, and the result is a nearly theoretically dense, nano-crystalline ceramic.

thermal energy

densification

ceramic


Input: Thick films were successfully deposited onto glass, steel and polyimide substrates via DAD.

glass

steel


Input: Surface roughness increased with thickness and with some influence from substrate material.

Surface roughness

substrate material


Input: Utilizing the DAD process, a very heterogeneous mixture of silicate and titanate mineral phases was transformed in a single step to a fully dense, nano-grained coating with spatially homogeneous composition at the micro-scale.

process

heterogeneous

step

homogeneous composition

micro-scale

silicate

fully dense

coating


Input: The final composition of the coatings was found to deviate slightly from the feedstock powder, becoming richer in ilmenite (FeTiO3) and poorer in plagioclase (feldspar) content.

composition

coatings

feedstock

ilmenite

feldspar


Input: This work demonstrates the potential of DAD for in-space manufacturing and lunar In Situ Resource Utilization.

manufacturing

In Situ


Input: Additive manufactured (AM) porous materials behave quantitatively and qualitatively differently in fatigue than bulk materials, and the relationships normally used for the fatigue design of continuous bulk materials are not applicable to AM porous materials particularly for low stiffness applications.This study investigated how the manufacturing methods and the material used during powder bed fusion affects the compressive strength and high cycle fatigue strength of a stochastic porous material for a given stiffness.

Additive manufactured

AM

AM

manufacturing

powder bed fusion

porous materials

material

porous material

quantitatively

materials

materials

materials

stochastic

fatigue

fatigue

stiffness

compressive strength

fatigue strength

stiffness

design


Input: Specimens were manufactured using varying laser parameters, 3 scan strategies (Contour, Points, Pulsing) and 4 materials.

manufactured

materials

laser

Contour


Input: The materials investigated were two titanium alloys: commercially pure grade 2 (CP-Ti) and Ti6Al4V ELI, commercially pure tantalum (Ta) and a titanium-tantalum alloy (Ti-30Ta) .The trends observed during fatigue testing for monolithic metals and statically for solid and porous AM materials were not always indicative of the high cycle fatigue behaviour of porous AM materials.

materials

trends

titanium alloys

tantalum

Ta

alloy

metals

AM materials

AM materials

fatigue testing

monolithic

porous

fatigue

porous


Input: Unlike their solid counterparts, porous tantalum and the titanium-tantalum alloy had the greatest fatigue strength for a given stiffness, 8% greater than CP-Ti and 19% greater than Ti6Al4V ELI.

porous

fatigue strength

stiffness

alloy


Input: Optimisation of the laser parameters and scan strategies was found to also increase the fatigue strength for a given stiffness of porous AM materials by 7–8%.

laser

fatigue strength

stiffness

porous

AM materials


Input: Selective laser melting (SLM) is an additive manufacturing technology which allows parts to be fabricated from metal powder using CAD data.

Selective laser melting

SLM

additive manufacturing

be

metal powder

CAD


Input: Today, standard metal powders like stainless steel, titanium, aluminium or copper are widely used with SLM technology.

standard

metal powders

stainless steel

titanium

aluminium

copper

SLM


Input: However, none of these materials is suitable for high-temperature applications up to more than 2000 °C such as the diagnostic and inner wall materials of a fusion reactor or experiment.

materials

materials

fusion

experiment

as


Input: As a primary task at the Central Institute of Engineering, Electronics and Analytics, development and manufacturing of high-temperature components for experimental setups are essentially demanded using new technologies and materials.

As

Engineering

Electronics

experimental

technologies

materials

manufacturing

components


Input: Therefore, molybdenum powder is investigated in terms of suitability for SLM technology in this study, due to the capability of molybdenum withstanding high temperature.

molybdenum

molybdenum

SLM

temperature


Input: Parameters like laser power, spot velocity and thickness of the powder layer are analysed to achieve high density of the parts.

Parameters

laser power

layer

powder

density


Input: Being able to characterize the process signatures of powder bed based additive manufacturing process is key to improving the product quality.

process

product quality

powder bed

additive manufacturing process


Input: This paper demonstrates the implementation of a digital fringe projection technique to measure surface topography of the powder bed layers during the fabrication.

surface topography

powder bed

fabrication


Input: We focus on developing the metrology tool and observing the types of information that can be extracted from such topographical data.

metrology

data

be


Input: The performance of the system is demonstrated with selected in situ measurements.

performance

in situ


Input: Experimental results show this system is capable of measuring powder bed signatures including the powder layer flatness, surface texture, the average height drop of the fused regions, characteristic length scales on the surface, and splatter drop location and dimension.

Experimental

average

fused

surface

powder bed

powder

layer

flatness

surface texture

dimension

length scales


Input: Mask projection stereolithography is a digital light processing-based additive manufacturing technique that has various advantages, such as high-resolution, scanning-free parallel process, wide material sets available, and support-structure-free three-dimensional (3D) printing.

Mask projection stereolithography

additive manufacturing

digital light processing-based

as

material

process

support-structure-free


Input: However, multi-material 3D printing with mask projection stereolithography has been challenging due to difficulties of exchanging a liquid-state material in a vat.

multi-material 3D printing

mask projection stereolithography

liquid-state

vat


Input: In this work, we report a rapid multi-material projection micro-stereolithography using dynamic fluidic control of multiple liquid photopolymers within an integrated fluidic cell.

multi-material

dynamic fluidic control

liquid photopolymers

fluidic cell


Input: Highly complex multi-material 3D micro-structures are rapidly fabricated through an active material exchange process.

multi-material

3D micro-structures

material exchange process

rapidly fabricated


Input: Material flow rate in the fluidic cell, material exchange efficiency, and the effects of energy dosage on curing depth are studied for various photopolymers.

Material flow rate

curing depth

fluidic cell

material exchange efficiency

energy dosage

photopolymers


Input: In addition, the degree of cross-contamination between different materials in a 3D printed multi-material structure is evaluated to assess the quality of multi-material printing.

cross-contamination

materials

structure

quality

3D printed

multi-material printing


Input: The pressure-tight and leak-free fluidic cell enables active and fast switch between liquid photopolymers, even including micro-/nano-particle suspensions, which could potentially lead to facile 3D printing of multi-material metallic/ceramic structures or heterogeneous biomaterials.

pressure-tight

leak-free

multi-material

fluidic cell

liquid photopolymers

micro-/nano-particle suspensions

lead

metallic/ceramic

heterogeneous biomaterials

3D printing


Input: In addition, a multi-responsive hydrogel micro-structure is printed using a thermo-responsive hydrogel and an electroactive hydrogel, showing various modes of swelling actuation in response to multiple external stimuli.

multi-responsive hydrogel

thermo-responsive hydrogel

electroactive hydrogel

swelling actuation

external stimuli


Input: This new ability to rapidly and heterogeneously integrate multiple functional materials in three-dimension at micro-scale has potential to accelerate advances in many emerging areas including 3D metamaterials, tissue engineering, and soft robotics.

heterogeneously

three-dimension

micro-scale

tissue engineering

multiple functional materials

3D metamaterials

areas

soft robotics


Input: Additive manufacturing (AM) allows for the production of custom parts with previously impractical internal features, but comes with the additional possibility of internal defects due to print error, residual stress buildup, or cyber-attack by a malicious actor.

Additive manufacturing

AM

production

print

defects

error

residual stress


Input: Conventional post process analysis techniques have difficulty detecting these defects, often requiring destructive tests that compromise the integrity (and thus the purpose) of the part.

process

defects

integrity


Input: Here, we present a “certify-as-you-build” quality assurance system with the capability to monitor a part during the print process, capture the geometry using three-dimensional digital image correlation (3D-DIC), and compare the printed geometry with the computer model to detect print errors in situ.

quality

monitor

geometry

three-dimensional

digital image correlation

geometry

errors

print

print

computer


Input: A test case using a fused filament fabrication (FFF) 3D printer was implemented, demonstrating in situ error detection of localized and global defects.

fused filament fabrication

FFF

3D printer

in situ

error

defects


Input: Selective laser melting (SLM) is a powder-based additive manufacturing technique which creates parts by fusing together successive layers of powder with a laser.

Selective laser melting

SLM

powder-based additive manufacturing

fusing

powder

laser


Input: The quality of produced parts is highly dependent on the proper selection of processing parameters, requiring significant testing and experimentation to determine parameters for a given machine and material.

quality

parameters

parameters

testing

machine

material


Input: Computational modeling could potentially be used to shorten this process by identifying parameters through simulation.

modeling

simulation

be

process

parameters


Input: However, simulating complete SLM builds is challenging due to the difference in scale between the size of the particles and laser used in the build and the size of the part produced.

SLM

builds

particles

laser

build


Input: Often, continuum models are employed which approximate the powder as a continuous medium to avoid the need to model powder particles individually.

continuum models

model

particles

powder

as


Input: While computationally expedient, continuum models require as inputs effective material properties for the powder which are often difficult to obtain experimentally.

continuum models

material properties

as

powder


Input: Building on previous works which have developed methods for estimating these effective properties along with their uncertainties through the use of detailed models, this work presents a part scale continuum model capable of predicting residual thermal stresses in an SLM build with uncertainty estimates.

properties

continuum model

residual

SLM

build


Input: Model predictions are compared to experimental measurements from the literature.

Model

experimental


Input: Processing of high-speed steel by SLM was successfully performed with low porosity.

steel

SLM

porosity


Input: Preheating temperatures of 200 °C or 300 °C are necessary for low crack density.

Preheating

density


Input: Microstructure consists of a cellular, fine dendritic structure after SLM.

Microstructure

structure

SLM


Input: Hardness tempering behavior of the SLM-densified material is promising.

Hardness

material


Input: The tribological properties of SLM specimens are highly promising compared to the references.

tribological properties

SLM


Input: In this work, the influence of different manufacturing techniques of M3:2 high-speed steel on the resulting microstructure and the associated material properties was investigated.

manufacturing

steel

microstructure

material properties


Input: Therefore, microstructure as well as the mechanical and tribological properties of cast steel (with subsequent hot-forming) and steel powder processed by two techniques: hot-isostatic pressing (HIP) and selective laser melting (SLM) were compared.

microstructure

tribological properties

processed

as

as

steel powder

mechanical

cast

pressing

HIP

selective laser melting

SLM


Input: A detailed SLM parameter analysis revealed that the porosity of SLM specimens can be decreased towards a smaller point distance and a longer exposure time (high energy input).

SLM

SLM

parameter

exposure

porosity

be


Input: A rise in preheating temperature is associated with a reduction in the crack density or the complete avoidance of cracks.

preheating

reduction

density


Input: In this context, the high-speed steel showed outstanding densification behavior by SLM, even though this steel is considered to be hardly processable by SLM due to its high content of carbon and hard phase-forming elements.

steel

steel

be

carbon

elements

densification

SLM

SLM


Input: In addition, the reusability of steel powder for SLM processing was investigated.

steel powder

SLM


Input: The results indicated that multiple reuse is possible, but only in combination with powder processing (mechanical sieving) after each SLM cycle.

powder

mechanical

SLM


Input: The microstructure of SLM-densified high-speed steel consists of a cellular, fine dendritic subgrain segregation structure (submicro level) that is not significantly affected by preheating the base plate.

microstructure

segregation

steel

preheating


Input: The mechanical and tribological properties were examined in relation to the manufacturing technique and the subsequent heat treatment.

mechanical

tribological properties

manufacturing

heat treatment


Input: Our investigations revealed promising behavior with respect to hardness tempering (position of the secondary hardness peak) and tribology of the M3:2 steel processed by SLM compared to the HIP and cast conditions.

hardness

hardness

tribology

processed

steel

SLM

HIP

cast


Input: A hybrid-part made of two materials was fabricated by selective laser melting (SLM) of AlSi10Mg on an Al-Cu-Ni-Fe-Mg cast alloy substrate.

materials

fabricated

selective laser melting

SLM

cast

alloy


Input: The microstructure of the two-material component and the interface is investigated using multi-scale characterization techniques including optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM).

microstructure

interface

component

optical microscopy

OM

scanning electron microscopy

SEM

electron backscatter diffraction

EBSD

transmission electron microscopy

TEM


Input: The microstructure of SLM-AlSi10Mg consists of fine cellular dendrites and columnar grains, developed along the building direction, where the substrate cast alloy is featured by large equiaxed grains.

microstructure

equiaxed grains

dendrites

columnar grains

building direction

substrate

alloy

cast


Input: OM and SEM studies of the interface show a sound metallurgical bonding as a result of the melting of AlSi10Mg powder and partial melting of the cast substrate assisted by the circulate flows and Marangoni convection.

OM

SEM

interface

metallurgical bonding

as

melting

melting

cast


Input: The circulate flows cause complex phenomena at the interface, which lead to the dilution of alloying elements and a variation in the microstructure of the first consolidated layer of SLM-AlSi10Mg (as a result of variation in thermal gradient and solidification rate).

interface

variation

microstructure

variation

lead

alloying elements

as

layer

thermal gradient

solidification rate


Input: TEM investigations of the interface reveal segregation of alloying elements at the interdendritic regions after solidification.

TEM

interface

segregation

solidification

alloying elements


Input: Moreover, no precipitate is formed on top of the interface, due to the rapid solidification and dilution of the alloying elements.

precipitate

alloying elements

interface

rapid solidification


Input: EBSD analysis of the interface shows substantial differences in the grain structure of SLM-AlSi10Mg and the cast substrate, in terms of size and morphology.

EBSD

interface

grain structure

morphology

cast


Input: Mechanical properties of the hybrid material are studied afterwards using Vickers microhardness measurements, nanoindentation and quasi-static uniaxial tensile tests.

Mechanical properties

microhardness

quasi-static

material

nanoindentation

tensile tests


Input: The SLM-AlSi10Mg side of the hybrid-part possesses better performance, mainly due to its finer and hierarchical microstructure.

performance

microstructure


Input: Inkjet printing of multiple materials is usually processed in multiple steps due to various jetting and curing/sintering conditions.

Inkjet printing

jetting

materials

processed


Input: The ink consists of iron oxide (Fe3O4) nanoparticles (nominal particle size 50–100 nm) suspended within a UV curable matrix resin.

ink

iron oxide

resin

nanoparticles

particle

UV


Input: The viscosity and surface tension of the inks were tuned to sit within the inkjet printability range.Multiple layers of the electromagnetic active ink were printed alongside passive UV-curable ink in a single manufacturing process to form a multi-material waffle shape.

viscosity

surface tension

inkjet

manufacturing process

ink

ink

multi-material


Input: The real permittivity of the cured passive ink, active ink and waffle structure at a frequency of 8–12 GHz were 2.25, 2.73 and 2.65 F/m, respectively.

cured

ink

ink

structure


Input: This shows the potential of additive manufacturing (AM) to form multi-material structures with tunable electromagnetic properties.

additive manufacturing

AM

multi-material structures

properties


Input: A side-viewing vision monitoring methodology using high-speed camera for powder bed fusion process is proposed.

methodology

camera

powder bed fusion process


Input: A novel method is designed to extract features from melt pool, plume and spatters.

designed

melt pool


Input: The characteristics of the features of melt pool, plume and spatters are investigated.

melt pool


Input: The results demonstrated that the extracted features are potential indicators for process quality assessment.

extracted

process


Input: With the development of powder bed fusion (PBF) additive manufacturing technique for functional parts production, process monitoring and diagnosis is highly demanded to ensure its process reliability and repeatability.

powder bed fusion

PBF

additive manufacturing

production

process monitoring

process

repeatability


Input: An optical filter with 350 nm–800 nm cut-off was used to enhance the image contrast between the plume and the melt pool.

optical

filter

image

melt pool


Input: A new image processing method was designed to extract features from the melt pool, plume and spatters, respectively.

image

designed

melt pool


Input: Kalman filter tracking was used to pinpoint the exact melt pool position, and image segmentation algorithm was developed to segment the melt pool, plume and spatters from each other; a new tracking method was utilized to remove the spatters generated in the previous frame.

filter

melt pool

melt pool

image

algorithm


Input: After image processing, the features of melt pool intensity, plume area, plume orientation, spatter number, spatter area, spatter orientation and spatter velocity were extracted and their correlations with the scanning quality were investigated.

image

orientation

orientation

extracted

scanning quality

melt pool

area

area

spatter

spatter

spatter

spatter


Input: The results indicated that these features were potential indicators for scanning quality assessment.

scanning quality


Input: The proposed method could be used to further study the characteristics of plume and spatter and to explore the diagnosis performance based on the fusion of melt pool, plume and spatter information.

be

melt pool

spatter

spatter

performance

fusion


Input: It provides a promising means for in-situ monitoring and control of PBF process.

in-situ

PBF


Input: This paper presents the computational fluid dynamics modeling of an additive manufacturing process that is candidate for the production of Gen IV nuclear reactor fuels.

computational fluid dynamics

additive manufacturing process

production

Gen IV


Input: The modeled process combines the internal gelation to produce metal hydrous oxides with the 3D ceramic printing to create a green body from these gelled oxides as described by Pouchon (2016).

process

internal gelation

green body

metal hydrous oxides

gelled oxides

as

3D ceramic printing


Input: The objective of the simulations is to optimize the process parameters: microfluidic mixing of the internal gelation reagents and generation of droplets of the mixed solutions.

simulations

process parameters

microfluidic mixing

internal gelation

droplets


Input: The simulations were performed using the OpenFOAM software, and to perform these simulations with the correct solution parameters, the properties of the fluids of interest were measured.

simulations

simulations

software

solution parameters

properties

fluids


Input: The results show that a thorough mixing of the metal solution and the methenamine and urea mixture in a microfluidic mixer can be achieved in tens of milliseconds by either winding the mixing channel to create secondary flows or splitting the solutions inlets to yield additional diffusion interfaces.

mixing

winding

secondary flows

diffusion interfaces

metal

methenamine

urea

be

microfluidic mixer

mixing channel

inlets


Input: The optimal droplet size is achieved by using a mechanically vibrating 3D printing head that leads to a frequency-following Rayleigh instability.

droplet size

mechanically vibrating

Rayleigh instability

3D printing head


Input: The results of the simulations suggest the parameters (micromixer geometry, flow rate, vibration frequency and others) that will optimize the mixing efficiency in a microfluidic mixer and the droplet generation process from a 3D printing head.

simulations

parameters

mixing efficiency

droplet generation

micromixer geometry

flow rate

vibration frequency

microfluidic mixer

3D printing head


Input: Metal Laser Sintering (LS) is a powder bed fusion process that can be used to produce manufactured parts of complex shapes directly from metallic powders.

Metal

be

metallic powders

Laser Sintering

powder bed fusion process

manufactured

complex shapes


Input: One of the major problems of such powder bed fusion processes is that during the continuous movement of the laser beam, temperature distribution becomes inhomogeneous and instable in the powder.

powder bed fusion processes

laser beam

distribution

temperature

powder


Input: It leads to greater residual stresses in the solidified layer.

residual stresses

layer


Input: Thus, temperature analyses must be performed to better understand the heating-cooling process of the powder bed as well as the interactions of different laser scanning paths within a sintering pattern.

temperature

be

as

as

process

pattern

powder bed

laser

sintering


Input: A transient 3D Finite Element (FE) model of the LS process has been developed with the commercial FE code ABAQUS.

transient 3D Finite Element

model

process

FE

FE

ABAQUS


Input: The model takes into account the different physical phenomena involved in this powder bed fusion technology (including thermal conduction, radiation and convection).

model

powder bed fusion

radiation


Input: A moving thermal source, modeling the laser scan, is implemented with the user scripting subroutine DFLUX in this FE code.

source

modeling

laser scan

FE


Input: The material’ s thermal behavior is also defined via the subroutine UMATHT.

material

s


Input: As the material properties change due to the powder bed fusion process, the model takes it into account.

As

material properties

model

powder bed fusion process


Input: In this way, the calculation of a temperature-dependent behavior is undertaken for the packed powder bed, within its effective thermal conductivity and specific heat.

powder bed

effective thermal conductivity

specific heat


Input: Furthermore, the model accounts for the latent heat due to phase change of the metal powder.

model

heat

phase

metal powder


Input: Finally, a time- and temperature-dependent formulation for the material’ s density is also computed, which is then integrated along with the other thermal properties in the heat equation.

material

s

density

thermal properties

heat


Input: FE simulations have been applied to the case of titanium powder and show predictions in good agreement with experimental results.

FE

titanium powder

predictions

experimental


Input: The effects of process parameters on the temperature and on the density distribution are also presented.

process parameters

temperature

density distribution


Input: The lattice structure is a type of cellular material that can achieve a variety of promising physical properties.

lattice structure

cellular material

physical properties


Input: Additive Manufacturing (AM) has relieved the difficulty of fabricating lattice structures with complex geometries.

Additive Manufacturing

AM

fabricating

complex geometries


Input: However, the quality of the AM fabricated lattice structure still needs improvement.

quality

AM

lattice structure


Input: In this paper, the influence of parameters of the Fused Deposition Modeling (FDM) process on lattice structures was investigated by the Taguchi method.

parameters

process

Taguchi method

Fused Deposition Modeling

FDM

lattice structures


Input: It was found that the optimum level and significance of each process parameter vary for horizontal and inclined struts.

process parameter

struts


Input: In addition, compression tests investigate the influence of process parameters on the mechanical properties of lattice structures.

compression tests

process parameters

mechanical properties

lattice structures


Input: The results show that process parameters optimized by print quality can also improve the elastic modulus and the ultimate strength of these lattice structures.

process parameters

print quality

elastic modulus

ultimate strength

lattice structures


Input: Laser cladding induces high tensile residual stress (RS), which can compromise the quality of a specimen.

Laser cladding

tensile residual stress

quality


Input: Therefore, it is critical to accurately predict the RS distribution in cladding and understand its formation mechanism.

accurately

distribution

mechanism

cladding


Input: In this study, functionally graded material (FGM) layers were successfully deposited on the surface of a titanium alloy Ti6Al4V sheet by laser cladding technology.

functionally graded material

titanium alloy Ti6Al4V sheet

FGM

laser cladding

surface


Input: A corresponding thermo-mechanical coupling simulation model of the laser cladding process was developed to investigate the formation mechanism of RS in the laser cladding FGM layers.

thermo-mechanical

model

mechanism

simulation

laser cladding

laser cladding

FGM layers


Input: The results show that high tensile RS forms in cladding components.

tensile

cladding


Input: Subsequent cladding can effectively alleviate the RS in cladding components although the position of maximum RS remains unchanged.

cladding

cladding


Input: The measurement results of the longitudinal RS on the top and bottom surfaces of cladding components by the X-ray diffraction (XRD) method agreed with the simulation results, thereby proving the accuracy of the simulation.

measurement

X-ray diffraction

XRD

accuracy

surfaces

cladding

simulation

simulation


Input: In addition, the formation mechanism of RS in the laser cladding FGM layers was revealed by discussing the individual impact of each material property on RS.

mechanism

impact

material property

laser cladding

FGM layers


Input: It was indicated that the RS distribution in the laser cladding FGM layers was significantly affected by material properties (in particular, coefficient of thermal expansion and Young’ s modulus), except for the temperature gradient induced by the laser cladding process.

distribution

material properties

laser cladding

laser cladding

FGM layers

s

coefficient of thermal expansion

temperature gradient


Input: The material extrusion additive manufacturing process, i.e., fused deposition modeling (FDM), as opposed to traditional subtractive manufacturing, offers a superior way of manufacturing tooling components in terms of great design flexibility, rapid tooling development, material requirement reduction and significant cost savings.

material extrusion additive manufacturing

fused deposition modeling

FDM

traditional subtractive manufacturing

manufacturing

rapid tooling

as

material

components

design flexibility

reduction


Input: However, it is always challenging to design a tool structure with minimized material and labor cost while maintaining satisfactory tooling performance.

design

tool

structure

labor cost

tooling performance

material


Input: In the current study, a comprehensive finite element model was developed for ULTEM 9085 FDM tools subjected to applied pressure and elevated temperature for vacuum assisted resin transfer molding (VARTM) process.

finite element model

pressure

process

FDM

resin transfer molding

temperature


Input: Both solid-build and sparse-build tools were studied.

tools


Input: Material properties of the tools were obtained from solid coupon testing at elevated temperatures.

Material properties

tools

testing

temperatures


Input: The thermo-mechanical behavior of tools during the VARTM process was investigated using the finite element model.

thermo-mechanical

process

finite element model

tools


Input: The ULTEM tools were manufactured using Stratasys Fortus 400mc FDM machine.

tools

manufactured

Stratasys

FDM


Input: Thermal cycling of the tools was performed at elevated temperatures (180 °F and 250 °F).

Thermal cycling

temperatures

tools


Input: Dimensional analysis and surface roughness of the tools were evaluated after thermal cycling.

Dimensional analysis

surface roughness

tools

thermal cycling


Input: This study on the performance of FDM tooling for VARTM composite manufacturing process can be extended to other composite manufacturing processes.

performance

FDM

composite manufacturing

composite manufacturing

be


Input: The low alloy steel AISI 4140 (German grade 42CrMo4) is one of the most frequently used Quench & Tempering (Q & T) steels with a wide range of applicability.

alloy steel

steels

Tempering

range


Input: Until now, commercially available iron powders for additive manufacturing can be summed up by their low amount of carbon.

iron

be

carbon

additive manufacturing


Input: Fusion welding of Q & T steels often leads to cracks due to brittle martensitic transformation and the associated volume change.

Fusion welding

steels

brittle

volume


Input: Therefore, the selection of appropriate process parameters in laser powder bed fusion (LPBF) plays a key role for the final material properties and is achieved through utilization of a new process development strategy and evaluation of microstructural features of test cubes.

process parameters

material properties

process

microstructural

laser powder bed fusion

LPBF


Input: In this work tensile specimens were successfully produced with optimal process parameters and mechanical tests of additively built samples indicate mechanical performance comparable with a 450 °C tempered state of conventionally cast material.

tensile specimens

optimal process

mechanical tests

samples

mechanical

tempered

cast


Input: By correlating the measured mechanical properties of LPBF samples to those of a conventional Q & T state, an estimation of the intrinsic heat treatment during LPBF was carried out using an inverse transient Hollomon–Jaffe approach.

mechanical properties

transient

LPBF

heat treatment

LPBF


Input: This is also in accordance with the finely dispersed carbide precipitates in the as built condition.

carbide

as


Input: Furthermore, the effect of bed pre-heating on the final material tempering state was found to be negligible.

bed

material

be


Input: This shows the importance of a balanced match between LPBF process parameters and subsequent application demands as well as necessary postprocessing steps.

LPBF

parameters

postprocessing

as

as


Input: Alumina toughened zirconia (ATZ) parts were produced via a laser-based powder bed fusion technology using a conventional Nd-YAG continuous wave laser.

Alumina

zirconia

powder bed fusion

continuous wave


Input: The powder was produced using a spray drying process and the laser matter interaction was enhanced by a binder pyrolysis.

powder

binder

spray drying

process

laser


Input: Thermal post-processing to further increase the part density was investigated using dilatometry.

post-processing

density


Input: The microstructure was analysed using X-ray powder diffraction measurements.

microstructure

X-ray powder diffraction


Input: The mechanical properties were assessed using a four-point bending test on ten specimens, reaching a bending strength of 31 ± 11 MPa.

mechanical properties

MPa

bending test

bending strength


Input: Laser-based direct metal addition (LBDMA) is a promising directed energy deposition technology that is well suited for the production of complex metal structures, low-volume manufacturing, and high-value component repair or modification.

metal

metal

directed energy deposition

production

manufacturing

component


Input: LBDMA is finding wide application in the automotive, biomedical, and aerospace industries.

automotive

biomedical

aerospace industries


Input: However, the process reliability and the repeatability of finished components are still problems.

process

repeatability

components


Input: This work offers a solution by developing a sensing and control system for the robotically controlled 8-axis LBDMA system developed at the Research Center for Advanced Manufacturing of Southern Methodist University, Dallas, TX.

solution

Research

sensing

control system

Manufacturing


Input: The developed system consists of sensing and control units for the powder flow rate and the molten pool size.

sensing

powder flow rate

molten pool


Input: An optoelectronic sensor was developed to sense the powder flow rate.

sensor

powder flow rate


Input: It is a main component in an on-line control system of powder flow rate in a LBDMA system.

component

control system

powder flow rate


Input: An infrared imaging setup was installed on the laser head to monitor the top full-field view of the molten pool.

infrared

monitor

molten pool

imaging

laser


Input: A simple proportional integral derivative (PID) controller, combined with feed-forward compensation was used to build a closed-loop control system for achieving a uniform molten pool size.

simple

controller

closed-loop control

build

molten pool


Input: Two L-shaped single-bead walls were built with and without closed-loop control, respectively.

closed-loop control


Input: A good performance on achieving uniform geometry by closed-loop control of the molten pool size was approved.

performance

geometry

molten pool

closed-loop control


Input: Selective laser sintering (LS) of thermoplastic powders allows for the construction of complex parts with higher mechanical properties and durability compared to other additive manufacturing methods.

Selective laser sintering

additive manufacturing

thermoplastic powders

construction

mechanical properties

durability


Input: According to the current model of isothermal laser sintering, semi-crystalline thermoplastics need to be processed within a certain temperature range, resulting in the simultaneous presence of the material both in a molten and solid state, which is present during part building.

model

isothermal

solid state

sintering

thermoplastics

be

material

temperature range


Input: Based on this process model, high cycle times ranging from hours to days are a thought to be a necessity to avoid warpage.In this paper, the limited validity of the model of isothermal laser sintering is shown by various experiments, as ongoing solidification could be detected a few layers below the powder bed surface.

process model

model

isothermal

solidification

be

as

be

sintering

powder bed


Input: The results indicate that crystallization and material solidification is initiated at high temperatures and further progresses throughout part build-up in z-direction.

crystallization

material

temperatures

z-direction


Input: Therefore, a process-adapted material characterization was performed to identify the isothermal crystallization kinetics at processing temperature and to track changes of the material state over time.

material

material

isothermal crystallization

temperature


Input: A dual approach on measuring surface temperatures by infrared thermography and additional thermocouple measurements in z-direction was performed to identify further influences on the material solidification.

surface

infrared

thermocouple

z-direction

material


Input: A model experiment revealed that a few millimeters below the surface, components produced by LS are already solidified.

model experiment

surface

components


Input: Based on these results, the authors present an enhanced process model of isothermal laser sintering, which considers material solidification in z-direction during part build-up.

process model

isothermal

sintering

material

z-direction


Input: Additive manufacturing (3D printing) enables the designing and producing of complex geometries in a layer-by-layer approach.

Additive manufacturing

3D printing

complex geometries

layer-by-layer


Input: The layered structure leads to anisotropic behaviour in the material.

layered structure

anisotropic

material


Input: To accommodate anisotropic behaviour, geometrical optimization is needed so that the 3D printed object meets the pre-set strength and quality requirements.

anisotropic

strength

optimization

quality

3D printed


Input: In this article a material description for polymer powder bed fused also or selective laser sintered (SLS) PA12 (Nylon-12), which is a common 3D printing plastic, was investigated, using the Finite Element Method (FEM).

material

polymer

bed

selective laser

SLS

3D printing

Finite Element Method

FEM


Input: The Material Model parameters were obtained by matching them to the test results of multipurpose test specimens (dumb-bells or dog bones) and the model was then used to simulate/predict the mechanical performance of the SLS printed lower-leg prosthesis components, pylon and support.

Material

parameters

model

mechanical

support

SLS

components


Input: For verification purposes, two FEM designs for a support were SLS printed together with additional test specimens in order to validate the used Material Model.

verification

FEM

designs

support

SLS

Material


Input: The SLS printed prosthesis pieces were tested according to ISO 10328 Standard.

SLS

ISO

Standard


Input: The FEM simulations, together with the Material Model, was found to give good estimations for the location of a failure and its load.

FEM

failure

Material


Input: It was also noted that there were significant variations among individual SLS printed test specimens, which impacted on the material parameters and the FEM simulations.

variations

FEM

SLS

material


Input: Hence, to enable reliable FEM simulations for the designing of 3D printed products, better control of the SLS process with regards to porosity, pore morphology and pore distribution is needed.

FEM

morphology

distribution

3D printed

SLS process

porosity

pore

pore


Input: Water-atomized and gas-atomized 17-4 PH stainless steel powder were used as feedstock in selective laser melting process.

17-4 PH stainless steel

as

selective laser melting process


Input: Gas atomized powder revealed single martensitic phase after printing and heat treatment independent of energy density.

Gas atomized

heat treatment

phase

energy density


Input: As-printed water atomized powder contained dual martensitic and austenitic phase regardless of energy density.

water atomized

powder

austenitic

energy density


Input: The H900 heat treatment cycle was not effective in enhancing mechanical properties of the water-atomized powder after laser melting.

heat treatment

mechanical properties

powder

laser


Input: However, after solutionizing at 1315ºC and aging at 482 °C fully martensitic structure was observed with hardness (40.2 HRC), yield strength (1000 MPa) and ultimate tensile strength (1261 MPa) comparable to those of gas atomized (42.7 HRC, 1254 MPa and 1300 MPa) and wrought alloy (39 HRC, 1170 MPa and 1310 MPa), respectively.

structure

MPa

MPa

MPa

MPa

wrought

MPa

MPa

hardness

yield strength

ultimate tensile strength

gas atomized

alloy


Input: Improved mechanical properties in water-atomized powder was found to be related to presence of finer martensite and higher volume fraction of fine Cu-enriched precipitates.

mechanical properties

powder

be

martensite

precipitates

volume fraction


Input: Our results imply that water-atomized powder is a promising cheaper feedstock alternative to gas-atomized powder.

powder

feedstock

powder


Input: Additive manufacturing (AM) technologies offer new processing routes for functionally graded materials.

Additive manufacturing

AM

technologies

functionally graded materials


Input: At present, parts built using these processes often require additional processing as a result of the characteristic surface finish limitations synonymous with AM processes.

processes

as

surface finish

AM processes


Input: A difficulty thus arises in the post processing of these components as volumes within the part have differing material properties by definition and will therefore exhibit variable machinability.In this study, machining of functionally graded Ti6Al4V/ WC components consisting of a metal matrix composite (MMC) region and a single alloy region produced via direct energy deposition using commercially available tooling is explored.

post processing

material properties

functionally graded

tooling

components

components

as

WC

metal matrix composite

MMC

alloy

machining

direct energy deposition


Input: The influence of post processing on surface integrity is investigated and reported.

post processing

surface integrity


Input: The effect of material variation on cutting forces and tool response along the component is also analysed and reported.

material

cutting forces

tool

component


Input: Cutting forces within the MMC region are found to increase by as much as 40% which has been subsequently related to the periodic changes in microstructure generated by the layer by layer build strategy.

Cutting forces

microstructure

layer by layer

build strategy

MMC

as

as


Input: Tool wear mechanisms are investigated and the influence of material pull out on surface integrity of both MMC and single material regions is explored.

Tool wear

material

MMC

material

surface integrity


Input: This study provides an insight into how the layer building strategies, particularly with multiple materials and the resulting variation in microstructure influences the machining of resulting components.

layer

materials

variation

microstructure

machining

components


Input: Additive manufacturing (AM) is gaining popularity because of its ability to manufacture complex parts in less time.

Additive manufacturing

AM

manufacture


Input: Despite recent research involving designs of experiments (DOEs) to characterize the relationships between some AM process parameters and various part quality characteristics, to date, there seems to be no universally accepted comprehensive model that relates process parameters to part quality.

research

quality

model

process parameters

quality

designs

AM process

be


Input: In this paper, to support the goal of manufacturing parts right the first time, a Bayesian network in continuous domain is developed which relates four process parameters (laser power, scan speed, hatch spacing, and layer thickness) and five part quality characteristics (density, hardness, top layer surface roughness, ultimate tensile strength in the build direction and ultimate tensile strength perpendicular to the build direction).

support

manufacturing

domain

process parameters

quality

laser power

scan speed

hatch spacing

layer thickness

layer

build direction

build direction

density

hardness

roughness

ultimate tensile strength

ultimate tensile strength


Input: A machine learning algorithm is used to train the network on a database mined from a large number of publications with experimental data from parts built using 316L with selective laser melting.

machine learning algorithm

database

experimental data

selective laser melting


Input: The network is validated by retaining a subset of the training data for testing and comparing the network’ s predictions to the known values.

data

predictions

testing

s


Input: Accuracy is optimized by continually re-training the network using parts built with a specific machine of interest.

Accuracy

machine


Input: The industrial relevance of this research is outlined with respect to four current challenges in AM, including the length of time to determine optimal process parameters for a new machine, ability to organize relevant knowledge, quantification of machine variability, and transfer of knowledge to new operators.

industrial

research

AM

optimal process

machine

machine


Input: Reclaimed materials such as waste plastics can be utilized in additive manufacturing to improve the self-reliance of warfighters on forward operating bases by cutting costs and decreasing the demand for the frequent resupplying of parts by the supply chain.

materials

supply chain

as

plastics

be

additive manufacturing

cutting


Input: In addition, the use of waste materials in additive manufacturing in the private sector would reduce cost and increase sustainability, providing a high-value output for used plastics.

materials

sustainability

additive manufacturing

plastics


Input: Experimentation is conducted to process polyethylene terephthalate bottles and packaging into filament that can then be used for additive manufacturing methods like fused filament fabrication, without the use of additives or modification to the polymer.

process

polyethylene terephthalate

filament

be

additives

polymer

additive manufacturing

fused filament fabrication


Input: The chemistry of different polyethylene terephthalate recycled feedstocks was evaluated and found to be identical, and thus mixed feedstock processing is a suitable approach.

chemistry

polyethylene terephthalate

feedstocks

be

feedstock


Input: Rheological data showed drying of the recycled polyethylene terephthalate led to an increase in the polymer’ s viscosity.

Rheological

data

recycled

drying

polyethylene terephthalate

polymer

s

led


Input: Thermal and mechanical properties were evaluated for filament with different processing conditions, as well as printed and molded specimens.

mechanical properties

filament

as

as


Input: Crystallinity ranged from 12.2 for the water cooled filament, compared to 24.9% for the filament without any active cooling.

filament

filament

cooling


Input: Tensile results show that the elongation to failure was similar to an injection molded part (3.5%) and tensile strength of 35.1 ± 8 MPa was comparable to commercial polycarbonate-ABS filament, demonstrating the robustness of the material.

Tensile

elongation

tensile strength

robustness

failure

MPa

filament

material


Input: In addition, three point bending tests showed a similar load at failure for a select long-lead military part printed from the recycled filament compared to parts printed from commercial filament.

three point bending

failure

recycled

military

filament

filament


Input: Thus filament from recycled polyethylene terephthalate has the capability for replacing commercial filament in printing a diverse range of plastic parts.

filament

polyethylene terephthalate

filament

plastic

recycled

range


Input: The incorporation of electrical components into 3D printed products such as sensors or printing of circuits requires the use of 3D printable conductive materials.

electrical

components

3D printed

as

materials


Input: However, most conductive materials available for fused filament fabrication (FFF) have conductivities of less than 1000 S/m.

materials

fused filament fabrication

FFF


Input: Here, we describe the study of conductive thermoplastic composites comprising either nylon–6 or polyethylene (PE) matrix.

thermoplastic composites

nylon

polyethylene

PE


Input: The fillers used were nickel and Sn95Ag4Cu1, a low melting point metal alloy.

nickel

alloy

melting point


Input: The combination of nickel metal particles and tin alloy allows for higher metal loading at lower melt viscosity, compared to composites of nickel metal particles alone.

nickel metal

tin alloy

metal

composites

nickel metal

melt


Input: % metal loading was processable by a single screw extruder.

metal

screw extruder


Input: Embedded conductive tracks of various geometries were easily printed via FFF.

geometries

FFF


Input: Electrical conductivity of embedded conductive track has been investigated as a function of geometrical variation, where conductive tracks printed along a horizontal axis show resistance of ≤ 1 Ω. Porosity of the printed track is shown to increase with prints along the vertical axis, leading to a reduction in electrical conductivity of more than two orders of magnitude.

Electrical conductivity

resistance

Porosity

electrical conductivity

as

variation

vertical

reduction

magnitude


Input: Rapid melt pool formation and solidification during the metal powder bed process Selective Laser Melting (SLM) generates large thermal gradients that can in turn lead to increased residual stress formation within a component.

melt pool

metal powder

lead

solidification

bed

component

Selective Laser Melting

SLM

thermal gradients

residual stress


Input: Metal anchors or supports are required to be built in-situ and forcibly hold SLM structures in place and minimise geometric distortion/warpage as a result of this thermal residual stress.

Metal

be

as

supports

in-situ

SLM

residual stress


Input: Anchors are often costly, difficult and time consuming to remove and limit the geometric freedom of this Additive Manufacturing (AM) process.

limit

geometric freedom

process

Additive Manufacturing

AM


Input: A novel method known as Anchorless Selective Laser Melting (ASLM) maintains processed material within a stress relieved state throughout the duration of a build.

as

Selective Laser Melting

processed material

stress

build


Input: As a result metal components formed using ASLM do not require support structures or anchors.

As

metal

components

support structures


Input: ASLM locally melts two or more powdered materials that alloy under the action of the laser and can form into various combinations of eutectic/hypo/hyper eutectic alloys with a new lower solidification temperature.

materials

eutectic

solidification

alloy

alloys

laser


Input: This new alloy is maintained in a semi-solid or stress reduced state throughout the build with the assistance of elevated powder bed pre-heating.

alloy

stress

build

powder bed


Input: In this paper the ASLM methodology is detailed and investigations into processing of a low temperature eutectic Al-Si binary casting alloy is explored.

methodology

eutectic

temperature

Al-Si

casting alloy


Input: Two types of Al powders were compared; pre-alloyed AlSi12 and elemental mix Al + 12 wt% Si.

Al

Al

Si


Input: The study established an understanding of the laser in-situ alloying process and confirmed successful alloy formation within the process.

laser

in-situ

process

alloying

alloy


Input: Differential thermal analysis, microscopy and X-Ray diffraction were used to further understand the nature of alloying within the process.

thermal analysis

microscopy

X-Ray diffraction

alloying

process


Input: Residual stress reduction was observed within ASLM processed elemental Al + Si12 and geometries produced without the requirement for anchors.

Residual stress

reduction

processed

geometries

Al


Input: Heterogeneous grain structure is a source of the inhomogeneity in structure and properties of the metallic components made by multi-layer additive manufacturing (AM).

Heterogeneous grain structure

structure

properties

source

metallic

components

additive manufacturing

AM


Input: During AM, repeated heating and cooling during multi-layer deposition, local temperature gradient and solidification growth rate, deposit geometry, and molten pool shape and size govern the evolution of the grain structure.

AM

heating

cooling

deposition

solidification

geometry

molten pool

evolution

grain structure

temperature gradient


Input: Here the effects of these causative factors on the heterogeneous grain growth during multi-layer laser deposition of Inconel 718 are examined by a Monte Carlo method based grain growth model.

heterogeneous

grain growth

deposition

grain growth

laser

Inconel 718


Input: It is found that epitaxial columnar grain growth occurs from the substrate or previously deposited layer to the curved top surface of the deposit.

epitaxial columnar grain

substrate

deposited layer

surface


Input: The growth direction of these columnar grains is controlled by the molten pool shape and size.

columnar grains

molten pool


Input: The grains in the previously deposited layers continue to grow because of the repeated heating and cooling during the deposition of the successive layers.

grains

deposition

deposited layers

heating

cooling


Input: Average longitudinal grain area decreases by approximately 80% when moving from the center to the edge of the deposit due to variable growth directions dependent on the local curvatures of the moving molten pool.

Average

grain

molten pool

area


Input: The average horizontal grain area increases with the distance from the substrate, with a 20% increase in the horizontal grain area in a short distance from the third to the eighth layer, due to competitive solid-state grain growth causes increased grain size in previous layers.

average

grain

grain

solid-state

grain growth

area

area

layer

substrate

grain size


Input: Powder quality in additive manufacturing (AM) electron beam melting (EBM) of Ti-6Al-4V components is crucial in determining the critical material properties of the end item.

Powder

additive manufacturing

AM

electron beam melting

EBM

components

material properties


Input: In this study, we report on the effect of powder oxidation on the Charpy impact energy of Ti-6Al-4V parts manufactured using EBM.

powder

oxidation

EBM

impact

manufactured


Input: In addition to oxidation, the effects on impact energy due to hot isostatic pressing (HIP), specimen orientation, and EBM process defects were also investigated.

oxidation

hot isostatic pressing

HIP

EBM

impact

orientation

defects


Input: This research has shown that excessive powder oxidation (oxygen mass fraction above 0.25% and up to 0.46%) dramatically decreases the impact energy.

research

fraction

impact

powder

oxygen

oxidation


Input: It was determined that the room temperature impact energy of the parts after excessive oxidation was reduced by about seven times.

temperature

impact

oxidation


Input: We also report that HIP post-processing significantly increases the impact toughness, especially for specimens with lower or normal oxygen content.

HIP

impact

oxygen


Input: The specimen orientation effect was found to be more significant for low oxidation levels.

orientation

be

oxidation


Input: Material extrusion 3D printing (ME3DP), based on fused deposition modeling (FDM) technology is currently the most widely available 3D printing platform.

Material extrusion 3D printing

fused deposition modeling

FDM

3D printing

technology


Input: As is the case with other 3D printing methods, parts fabricated from ME3DP will exhibit physical property anisotropy where build direction has an effect on the mechanical properties of a given part.

As

3D printing

fabricated

mechanical properties

physical property

anisotropy

build direction


Input: The work presented in this paper analyzes the effect of physical property-altering additives to acrylonitrile butadiene styrene (ABS) on mechanical property anisotropy.

additives

acrylonitrile butadiene styrene

ABS

mechanical property

anisotropy


Input: A total of six ABS-based polymer matrix composites and four polymer blends were created and evaluated.

polymer matrix composites

polymer blends


Input: Tensile test specimens were printed in two build orientations and the differences in ultimate tensile strength and% elongation at break were compared between the two test sample versions.

Tensile test

build orientations

ultimate tensile strength

elongation

sample


Input: Fracture surface analysis was performed via scanning electron microscopy (SEM) which gave insight to the failure modes and rheology of the novel material systems as compared to specimens fabricated from the same ABS base resin.

Fracture

fabricated

scanning electron microscopy

SEM

failure modes

rheology

material

as

ABS

resin


Input: Here it was found that a ternary blend of ABS combined with styrene ethylene butadiene styrene (SEBS) and ultra high molecular weight polyethylene (UHMWPE) lowered the mechanical property anisotropy in terms of relative UTS to a difference of 22 ± 2.07% as compared to 47 ± 7.23% for samples printed from ABS.

blend

ABS

polyethylene

as

ABS

weight

mechanical property

samples

anisotropy

UTS


Input: The work here demonstrates the mitigation of a problem associated with 3D printing as a whole through novel materials development and analyzes the effects of adding a wide variety of materials on the physical properties of a thermoplastic base resin.

3D printing

materials

materials

physical properties

thermoplastic

resin


Input: Moisture affects the flow behavior of AM metal powders, where AlSi10Mg is the most sensitive to water and oxygen pick up.

AM metal

oxygen


Input: The powder morphology influences to a large extent the moisture pick up and flow behavior.

powder

morphology


Input: The flowability measured with traditional tools is not representative for powder bed fusion processes.

tools

powder bed fusion processes


Input: Two new flowability tools that mimic the powder spreading mechanism of powder bed fusion systems are proposed and tested.

tools

mimic

powder

mechanism

powder bed fusion


Input: Air drying and vacuum drying treatments to remove the moisture prior to the build process are investigated.

drying

drying

build


Input: For AM processes—specifically Laser Powder Bed Fusion (L-PBF) processes—powder flowability is essential for the product quality, as these processes are based on a thin layer spreading mechanism.

AM

Laser Powder Bed Fusion

L-PBF

product quality

processes

mechanism

as

layer


Input: However, the available techniques to measure this flowability do not accurately represent the spreading mechanism.

accurately

mechanism


Input: Hence, this paper presents two novel applicator tools specifically designed to test the spreadability of l-PBF powders in thin layer application.

tools

designed

l-PBF

layer


Input: The results were checked by running standard tests to analyze the powder morphology, moisture content, chemical composition and flowability using the Hall-flowmeter.

standard

morphology

chemical composition

powder


Input: For this study, four common l-PBF metal powders were selected: Inconel 718, Ti6Al4V, AlSi10Mg and Scalmalloy.

l-PBF

powders

Inconel 718


Input: From the as-received state, drying (vacuum and air) and moisturizing treatments were applied to compare four humidity states and investigate the feasibility of pre-treating the powders to remove moisture, which is known to cause problems with flowability, porosity formation and enhanced oxidation.

drying

oxidation

feasibility

powders

porosity


Input: The tests reveal that AlSi10Mg is the most susceptible alloy to moisture and oxygen pick-up, considerably decreasing the spreadability and relative density on the build platform.

alloy

oxygen

relative density

build platform


Input: However, the results also reveal how challenging the direct measurement of moisture levels in metal powders is.

measurement

metal powders


Input: Therefore, lightweight is paramount.Here, a lightweight electromagnetic actuator for HHBs is conceived using Design for Additive Manufacturing (DfAM) tools, including topology optimization and free-shape design.

lightweight

lightweight

actuator

tools

Design for Additive Manufacturing

topology optimization

design


Input: A prototype is manufactured by selective laser melting (SLM) of alloy Ti-6Al-4V.

prototype

manufactured

selective laser melting

SLM

alloy


Input: The prototype weighs 25% less than the actuator designed and manufactured using traditional methods (i.e.

prototype

manufactured

actuator


Input: CAD, milling) and materials (i.e.

CAD

milling

materials


Input: Al alloys).

Al alloys


Input: The performance of the actuator in service is simulated by transient modal mechanical analyses using finite element methods.

performance

transient

mechanical analyses

finite element methods

actuator


Input: The results show that the high strength of the material selected, combined with the bionic geometry designed and the resulting lightweight, allow the actuator to withstand the extreme accelerations of the HHB (3000 g) without yielding, enabling ultra-fast switching –namely, below 1 ms.

strength

material

geometry

lightweight

designed

actuator