Input: The results showed that the highest mechanical properties and tribological performance were obtained for 316L SS specimens produced by Selective Laser Melting, when compared to Hot Pressing and conventional casting.

mechanical properties

tribological performance

SS

Selective Laser Melting

Hot Pressing

casting


Input: The high wear and mechanical performance of 316L Stainless Steel fabricated by Selective Laser Melting are mainly due to the finer microstructure, induced by the process.

wear

process

mechanical

316L Stainless Steel

Selective Laser Melting

finer microstructure


Input: In this sense, Selective Laser Melting seems a promising method to fabricate customized 316L SS implants with improved mechanical and wear performance.

Selective Laser Melting

fabricate

SS

implants

mechanical

wear performance


Input: This original work proposes to investigate the transposition of crystallography rules to cubic lattice architectured materials to generate new 3D porous structures.

crystallography

lattice

materials


Input: The application of symmetry operations provides a complete and convenient way to configure the lattice architecture with only two parameters.

lattice

parameters

architecture


Input: New lattice structures were created by slipping from the conventional Bravais lattice toward non-compact complex structures.

lattice structures

lattice

complex structures


Input: The resulting stiffness of the porous materials was thoroughly evaluated for all the combinations of architecture parameters.

stiffness

porous materials

architecture


Input: This exhaustive study revealed attractive structures having high specific stiffness, up to twice as large as the usual octet-truss for a given relative density.

specific stiffness

relative density

as

as


Input: It results in a relationship between effective Young modulus and relative density for any lattice structure.

Young modulus

relative density

lattice structure


Input: The collection of the elastic properties for all the cubic structures into 3D maps provides a convenient tool for lattice materials design, for research, and for mechanical engineering.

elastic

cubic structures

design

lattice

research

tool

mechanical engineering


Input: The resulting mechanical properties are highly variable according to architecture, and can be easily tailored for specific applications using the simple yet powerful formalism developed in this work.

mechanical properties

architecture

be

simple


Input: A volumetric, mini extruder for pellets or granules of recycled plastic that can be used in a RepRap FDM 3D printer for rapid prototyping is discussed.

extruder

RepRap FDM 3D printer

pellets

granules

recycled

plastic

be

rapid prototyping


Input: The steer Auger portion is added to increase the pressure inside a helix stator container of n-lobes as a helical rotor is turned.

Auger

pressure

as


Input: A novel, alternative multi-layer Moineau-based pump −easier to build, implement and clean– is also introduced to extrude a quantity of viscous material in vertical direction.

build

extrude

material

vertical


Input: In laser powder bed fusion (PBF-LB), material is continuously ejected from the melt pool, commonly called spatter, and is distributed throughout the build chamber.

laser powder bed fusion

material

melt pool

spatter

build chamber


Input: There is a lack of understanding of the nature of this spatter and the effect it may have on the integrity of the final part and the quality of any recycled powder.

spatter

integrity

quality

recycled

powder


Input: This work reports a detailed investigation of spatter metallurgy for Inconel 718.

spatter

metallurgy

Inconel 718


Input: It is seen that the spatter created during processing produces powder that is significantly different to the virgin material, with particles up to 6 times larger.

spatter

powder

material

particles


Input: Oxidation, predominantly in the form of spots or films of Al2O3 and TiO2 was observed on the surface of some of the spatter particles.

Oxidation

surface

particles

spatter


Input: It is established that this oxide formation occurs at the melt pool surface before ejection of the spatter from the melt pool, and also that this issue is generic to PBF-LB process and certain alloys.

oxide

melt pool

melt pool

alloys

ejection

process

spatter


Input: The characteristics of different types of spatter are identified and are linked to spatter generation mechanisms.

spatter

spatter


Input: The vaporisation of material during processing produces clusters of nano particles whose composition indicate a preferential vaporisation of Cr from the bulk.

material

Cr

nano

composition


Input: The results of this study highlight that oxidation and issues presented by spatter particles dissimilar from the virgin material are unavoidable and greater consideration is needed for the generation and effect of spatter on part and powder quality.

oxidation

spatter

spatter

particles

material

powder


Input: The paper describes a new approach in controlling and tailoring residual stress profile of parts made by Selective Laser Melting (SLM).

residual stress

profile

Selective Laser Melting

SLM


Input: SLM parts are well known for the high tensile stresses in the as–built state in the surface or subsurface region.

SLM

tensile stresses

as

surface


Input: These stresses have a detrimental effect on the mechanical properties and especially on the fatigue life.

mechanical properties

fatigue life


Input: Laser Shock Peening (LSP) as a surface treatment method was applied on SLM parts and residual stress measurements with the hole–drilling method were performed.

Laser

Peening

surface treatment

SLM

drilling

as

residual stress


Input: Two different grades of stainless steel were used: a martensitic 15-5 precipitation hardenable PH1 and an austenitic 316L.

stainless steel

austenitic

precipitation


Input: Different LSP parameters were used, varying laser energy, shot overlap, laser spot size and treatments with and without an ablative medium.

parameters

laser energy

overlap

laser spot size


Input: For both materials the as-built (AB) residual stress state was changed to a more beneficial compressive state.

materials

AB

residual stress


Input: The value and the depth of the compressive stress was analyzed and showed a clear dependence on the LSP processing parameters.

compressive stress

parameters


Input: The use of LSP during the building phase of SLM as a “3D LSP” method would possibly give the advantage of further increasing the depth and volume of compressive residual stresses, and selectively treating key areas of the part, thereby further increasing fatigue life.

phase

volume

SLM

as

residual stresses

fatigue life

areas


Input: Template-free 3D printing of electronic devices has the potential to broaden electronics integration to include complex integrated form factors, but success requires precise, adaptive control over materials processing.

3D printing

electronics

adaptive control

materials processing


Input: The development of such manufacturing technologies requires exploration of new combinations of ink sets, printing techniques, and automation strategies.

manufacturing technologies

ink

automation


Input: A closed-loop feedback system that links deposition parameters with characterization was necessary to maintain μm-precision deposition for over 20 h without human involvement.

feedback

deposition

deposition


Input: This closed-loop control scheme enabled 3D printing of both single- and double-layer high-voltage capacitors with capacitances as large as 314 pF (at 1 kHz) and breakdown voltages over 1000 V, which is significant step towards repeatable template-free, 3D printing of electronics for rapid prototyping of multifunctional devices.

closed-loop control

3D printing

3D printing

capacitors

as

as

V

step

electronics

rapid prototyping


Input: The precise control over low minimum feature dimension, high breakdown voltage, and long print duration enables the exploration of a broader range of printed electronics application than conventional 3D printing techniques.

precise control

printed electronics

feature dimension

print

3D printing

range


Input: Three-dimensional (3D) printing can be a promising tool in tissue engineering applications for generating tissue-specific 3D architecture.

Three-dimensional

tissue engineering

be

tool


Input: The 3D printing process, including computer-aided design (CAD), can be combined with the finite element method (FEM) to design and fabricate 3D tissue architecture with designated mechanical properties.

3D printing

fabricate

computer-aided design

CAD

be

finite element method

FEM

mechanical properties

design

architecture


Input: In this study, we generated four types of 3D CAD models to print tissue-engineered scaffolds with different inner geometries (lattice, wavy, hexagonal, and shifted microstructures) and analyzed them by FEM to predict their mechanical behaviors.

geometries

lattice

FEM

print

scaffolds

hexagonal

microstructures

mechanical


Input: For the validity of computational simulations by FEM, we measured the mechanical properties of the 3D printed scaffolds.

simulations

FEM

mechanical properties

3D printed


Input: Results showed that the theoretical compressive elastic moduli of the designed constructs were 23.3, 56.5, 67.5, and 1.8 MPa, and the experimental compressive elastic moduli were 23.6 ± 0.6, 45.1 ± 1.4, 56.7 ± 1.7, and 1.6 ± 0.2 MPa for lattice, wavy, hexagonal, and shifted microstructures, respectively, while maintaining the same construct dimension and porosity.

theoretical

MPa

experimental

MPa

lattice

elastic moduli

elastic moduli

porosity

designed

hexagonal

dimension

microstructures


Input: In addition, van der Waals hyperelastic material model was successfully utilized to predict the nonlinear mechanical behavior of the printed scaffolds with different inner geometries.

material

mechanical

scaffolds

geometries


Input: These findings indicated that the CAD-based FEM prediction could be used for designing tissue-specific constructs to mimic the mechanical properties of targeted tissues or organs.

FEM

mechanical properties

be

mimic


Input: The optical penetration depth of the laser beam into the powder bed is taken into account in this model.

optical

laser beam

model

powder bed


Input: The convective heat flux dominate the heat tranfer in the molten pool, and further decides the shape of molten pool.

heat flux

heat

molten pool

molten pool


Input: Heat accumulation can significantly change the size of the molten pool, but has little effect on the molten pool shape.

Heat accumulation

molten pool

molten pool


Input: A physical model coupled with heat transfer and fluid flow was developed to investigate the thermofluid field of molten pool and its effects on SLM process of Inconel 718 alloy, in which a heat source considering the porous properties of powder bed and its reflection to laser beam is used.

physical model

heat transfer

molten pool

process

heat source

laser beam

fluid flow

porous

SLM

Inconel 718 alloy

powder bed

reflection


Input: The simulation results showed that surface tension caused by temperature gradient on the surface of molten pool drives to Marangoni convection, which makes fluid flow state mainly an outward convection during SLM process.

simulation

surface tension

fluid flow

temperature gradient

surface

molten pool

process

SLM


Input: Marangoni convection includes convective and conductive heat flux, both of them have effects of on molten pool shape, but the effect of convective heat flux is dominant because its magnitude is one order larger than that of conductive heat flux.

heat flux

molten pool

heat flux

heat flux

magnitude


Input: The convective heat flux accelerates the flow rate of the molten metal, benefits to heat dissipation.

heat flux

heat dissipation

flow rate

molten metal


Input: The convective heat flux makes the molten pool wider, while the conductive heat flux makes comparably the molten pool deeper and wider.

heat flux

molten pool

heat flux

molten pool


Input: Furthermore, heat accumulation caused by multiple scanning increases convection and conduction heat flux resulting in the increase of the width and depth of the molten pool, but no change of dominant role of convective heat flux to the shape of the molten pool.

heat accumulation

scanning

heat flux

molten pool

heat flux

molten pool


Input: A staircase Inconel 718 block was fabricated to investigate the effects of the thermal cycles on the microstructure evolution in the selective laser melting (SLM) part using optical scope (OM), scanning electron microscope (SEM), and electron backscatter diffraction (EBSD).

Inconel 718

fabricated

microstructure evolution

thermal cycles

selective laser melting

SLM

optical

OM

SEM

electron backscatter diffraction

EBSD

scanning electron microscope


Input: The laser beam scanning strategy was clearly shown in the part under OM, including laser scanning pattern and hatch spacing.

laser beam

pattern

OM

laser

hatch spacing


Input: The Y-plane (side surface) was characterized by elongated colonies of cellular dendrites with an average cell spacing of 0.511 ∼ 0.845 μm.

surface

average

dendrites


Input: In addition, Laves phase was observed in the inter-layers and inter-cellular regions.

Laves phase


Input: Under the continuing effects of the thermal cycles, the fraction of the Laves-phase showed a significant drop with their morphology changing from coarse and interconnected particles to discrete Laves phase.

thermal cycles

fraction

morphology

particles

Laves phase


Input: This is attributed to the reheating process as Laves phase can be dissolved at a proper heat treatment.

process

phase

as

be

heat treatment


Input: In terms of the width of the cellular dendrites, the longer the thermal cycle period is, the coarser the elongated grains are.

dendrites

thermal cycle

grains


Input: With the repeating thermal cycle period elongating, the maximum intensity of the texture, together with the fraction of larger grains and the high misorientation angles, increased.

thermal cycle

texture

fraction

grains


Input: Moreover, the area fraction of the porosity was below 0.2%, with no remarkable effects found from the thermal cycles and the build height.

area

thermal cycles

build height

porosity


Input: Simulations capable of predicting the complex thermal behavior which occurs in a selective laser melting (SLM) process would help design and manufacturing engineers build more optimum designs in a reliable manner.

Simulations

selective laser melting

SLM

manufacturing

process

design

designs

build


Input: A multiscale feed forward adaptive refinement and de-refinement (FFD-AMRD) finite element framework has been developed in response to this need.

feed

finite element


Input: Support structures fabricated during SLM to overcome residual stress induced part distortion are a key part of the process, and a representation of these support structures in a finite element framework must be considered.

Support structures

support structures

fabricated

distortion

process

finite element

SLM

residual stress

be


Input: If support structures could be designed with minimal material usage while still maintaining an ability to withstand the residual stresses generated during the part fabrication, this would significantly impact industrial use of SLM.

support structures

be

material

residual stresses

fabrication

SLM

impact


Input: In this work, the effective thermal properties of support structures are represented using thermal homogenization.

thermal properties

support structures

homogenization


Input: The effective thermal properties of the support structures have been found to be a function of their geometry, anisotropy and constituent independent thermal properties.

thermal properties

geometry

thermal properties

support structures

be

anisotropy


Input: The objective of this work is to derive effective thermal property functions which could be directly incorporated in the FFD-AMRD framework mentioned above to enhance computational speed.

thermal property

framework

be

computational speed


Input: Polymer Laser Sintering (LS) is a well-known Additive Manufacturing process, capable of producing highly complex geometries with little or no cost penalty.

Polymer Laser Sintering

Additive Manufacturing process

complex geometries


Input: However, the restricted range of materials currently available for this process has limited its applications.

range

materials

process


Input: Whilst it is common to modify the properties of standard LS polymers with the inclusion of fillers e.g.

properties

standard

polymers

inclusion


Input: nanoclays, achieving effective dispersions can be difficult.

be


Input: The work presented here investigates the use of plasma treatment as a method of enhancing dispersion with an expectation of improving consistency and surface quality of laser sintered nanocomposite parts.

investigates

plasma

dispersion

consistency

as

surface quality

laser


Input: To enable the preparation of polyamide 12 nanocomposite powder for applications in LS, plasma surface modification using Low Pressure Air Plasma Treatment was carried out on two nanoclays: Cloisite 30B (C30B) and Nanomer I.34TCN (I.34TCN).

polyamide 12

powder

plasma

Pressure

Plasma


Input: Plasma treatment strongly reduced the aggregation of the nanoclay (C30B and I.34TCN) particles, and powders displayed higher decomposition temperatures than those without plasma treatment.

Plasma

particles

plasma

powders

decomposition


Input: LS parts from neat polyamide 12, untreated I.34TCN and plasma treated I.34TCN composites were successfully produced with different complex shapes.

polyamide 12

composites

plasma

complex shapes


Input: The presence of well dispersed plasma treated nanoclays was observed and found to be essential for an improved surface quality of LS fabricated which was achieved only for plasma treated I.34TCN.

plasma

fabricated

plasma

be

surface quality


Input: Likewise, some mechanical properties could be improved above that of PA12 by incorporation of treated I.34TCN.

mechanical properties

be


Input: For example, the elastic modulus of plasma treated composites was higher than that of polyamide 12 and the untreated composite.

elastic modulus

plasma

composites

polyamide 12

composite


Input: In the case of the ultimate strain, the plasma treated composite performed better than untreated and results had a reduced variation between samples.

strain

plasma

variation

samples

composite


Input: This illustrates the feasibility of the use of plasma treatments on nanoclays to improve the properties of LS parts, even though further studies will be required to exploit the full potential.

feasibility

plasma

properties

be


Input: Accuracy in dental prosthesis plays a significant role.

Accuracy

dental prosthesis


Input: Surgical guides are widely used for accurate positioning of dental implants.

accurate

dental


Input: Designing of guides using modern software is useful in achieving precision; however, translation of these images into actual fabricated parts can be achieved using Three-dimensional (3-D) printing.

software

images

fabricated

Three-dimensional

precision

be


Input: Conventionally, guides were fabricated using vacuum forming technique which leads to several dimensional inaccuracies.

fabricated

forming


Input: Computed Tomography (CT) images of patients with missing teeth are modeled to design surgical guide using Computer Aided Design (CAD)/Computer Aided Manufacturing (CAM) software which is then combined with surface scan files in Standard Tessellation Language (STL) formats to design the guide.

Computed Tomography

CT

Computer Aided Design

CAD

Computer Aided Manufacturing

CAM

images

software

surface

design

design

files

Standard Tessellation Language

STL


Input: In this work, surgical guides have been 3-D printed using different technologies like Material Jetting technology (MJT), Vat photopolymerization (VP) and Material extrusion (ME).

technologies

Material Jetting

Vat photopolymerization

Material extrusion


Input: Depth, diameter, Area and Volume of the printed guides have been calculated using vernier caliper and scan measurements.

diameter

Volume

Area

vernier caliper


Input: These dimensions have then been compared with the dimensions obtained from software modeled images.

dimensions

dimensions

software

images


Input: Least error has been found for the guides fabricated using MJT.

error

fabricated


Input: The experimental work in this paper, hence, suggests MJT be the most preferred printing technique due to its superior accuracy for printing dental prosthesis like aligners, implants, and crowns, etc.

experimental

be

accuracy

dental prosthesis

implants


Input: Four distinct TPU grades are analyzed for the use in laser sintering.

laser sintering


Input: Clear links between material properties and sintering behavior are established.

material properties

sintering


Input: Guidelines for future selection of TPU grades for laser sintering are deduced.

laser sintering


Input: As laser sintering is increasingly being used for the production of actual end-use parts, there is considerable interest in developing materials that would enable new applications for this technique.

As

sintering

production

materials


Input: Considering their properties and current applications, elastomeric polymers such as thermoplastic polyurethanes (TPU) have a very high potential in this regard.

properties

polymers

as

polyurethanes


Input: This study investigates the material properties that are involved in TPU sintering through the analysis of four distinct TPU grades.

investigates

material properties

sintering


Input: Examined parameters include powder flow, rheology of the melt and shrinkage and hardening behavior.

parameters

melt

shrinkage

powder

rheology

hardening


Input: It is found that, even though the particle morphology is not optimum, smooth and dense powder layers can be deposited for the investigated powders.

particle

morphology

powder

be

powders


Input: Low melt viscosity and low shrinkage upon hardening further enable these materials to be easily processed into functional parts.

melt

shrinkage

materials

processed

hardening

be


Input: Remaining issues, however, are part porosity and material degradation.

porosity

material

degradation


Input: The findings in this study provide clear links between material properties and behavior during laser sintering, and result in guidelines for future selection of TPU grades.

material properties

laser sintering


Input: Support structures are critical to the successful printing of the overhang structures in selective laser melting.

Support structures

overhang

selective laser melting


Input: The heat transfer performance of support structures has significant influence on the temperature distribution and cooling rate within the overhang structures which in turn determine the microstructure and residual stress.

heat transfer

distribution

microstructure

support structures

temperature

cooling rate

overhang

residual stress


Input: In the present study, functionally graded support structures have been proposed and their thermal performance has been numerically investigated, with the consideration of different materials, cooling times and gradedness values.

functionally graded

performance

materials

cooling


Input: It has been found that functionally graded support structures can maintain a higher temperature level than the conventional uniform support structure at the bottom of overhang, which is equivalent to an extra pre-heating effect.

functionally graded

temperature

overhang

support structure


Input: The temperature fluctuation and cooling rate at the bottom of overhang can also be reduced by adopting the functionally graded support structures.

temperature

cooling rate

overhang

be

functionally graded


Input: Topology-optimized structure has ultrahigh normalized fatigue life of 0.65 at 106 cycles and low density.

structure

fatigue life

density


Input: Topology-optimized structure increases fatigue life by reducing stress concentration.

structure

fatigue life

stress concentration


Input: Twinning formed in porous CP-Ti samples enhances plasticity and fatigue properties.

Twinning

samples

porous

plasticity

fatigue


Input: The fatigue properties are critical considerations for porous structures, and most of the existing porous materials have unsatisfactory performances due to a lack of structural optimization.

fatigue

porous

porous materials

structural optimization


Input: This work shows that a topology-optimized structure fabricated by selective laser melting using commercial-purity titanium (CP-Ti) exhibits excellent fatigue properties with an ultra-high normalized fatigue life of ∼0.65 at 106 cycles and at a low density of 1.3 g/cm3.

structure fabricated

selective laser melting

titanium

fatigue

fatigue life

density


Input: The main factors affecting fatigue, i.e., material properties and a porous structure were studied.

fatigue

porous

material properties


Input: Both the factors can affect the fatigue crack initiation time, thereby affecting the fatigue life.

fatigue

fatigue life


Input: Because of twinning that occurred during the fatigue process, the porous CP-Ti samples exhibit a high plasticity.

twinning

samples

fatigue

porous

plasticity


Input: In addition, the fatigue crack propagation rate is significantly reduced because of the high plasticity of the CP-Ti material and the occurrence of fatigue crack deflection.

fatigue

plasticity

fatigue

crack propagation rate

material


Input: Microstructure evolution in the molten pool of SLM-processed parts was disclosed.

Microstructure evolution

molten pool


Input: Variation of microhardness with local zone within the molten pool were measured.

Variation

microhardness

molten pool


Input: Thermal behavior within the molten pool was quantitatively analyzed.

molten pool

quantitatively


Input: Relationship among microstructure, properties and thermal behavior was discussed.

microstructure

properties


Input: This work presented a comprehensive study of microstructural evolution, microhardness and quantitative thermodynamic analysis within the molten pool during Selective Laser Melting (SLM) of Inconel 718 parts.

microstructural evolution

microhardness

quantitative

molten pool

Selective Laser Melting

SLM

Inconel 718


Input: Microstructures and corresponding microhardness of different zones within the molten pool experienced the following evolution: fine cellular dendrites or equiaxed grains on the top surface (387HV); columnar dendrites with single direction of grain growth at the bottom (337HV); columnar dendrites with multiple directions of grain growth at the edge of the molten pool (340HV-350HV); microstructures between cellular and columnar grains around the center of the molten pool (363HV).

Microstructures

columnar dendrites

columnar dendrites

microstructures

microhardness

molten pool

evolution

equiaxed grains

surface

grain growth

grain growth

molten pool

molten pool

dendrites

columnar grains


Input: The impact of Gaussian-distributed laser energy and relatively weak thermal conductivity and convection of Inconel 718 contributed to the variation of temperature gradient at different zones within the molten pool.

impact

laser energy

variation

molten pool

thermal conductivity

Inconel 718

temperature gradient


Input: The formation of different kinds of microstructures in the molten pool was controlled by the temperature gradient (which determined the direction of grain growth) and the cooling rate (which determined the size of grain growth).

microstructures

molten pool

grain growth

grain growth

temperature gradient

cooling rate


Input: The variation of microhardness within the molten pool was ascribed to the number of grain boundaries and the stress characteristics of different kinds of microstructures under mechanical load.

variation

microhardness

molten pool

grain boundaries

stress

microstructures

mechanical


Input: The zones with fine cellular grains had elevated mechanical performance due to the superior capability to endure the load.

cellular grains

mechanical


Input: This work hopefully provides scientific and theoretical support for SLM-processed Inconel 718 parts with favorable properties.

theoretical

properties

support

Inconel 718


Input: With a view to developing a highly biocompatible and highly reliable material for artificial hip joints, cellular lattice structures with high strength and low Young’ s modulus (E) were designed using computational shape optimization.

biocompatible

strength

material

s

hip

lattice structures

designed

optimization


Input: These structures were fabricated from a biomedical Co-Cr-Mo alloy via electron beam melting.

fabricated

biomedical

alloy

electron beam melting


Input: As a starting point for shape optimization, inverse body-centered-cubic (iBCC) -based structures with different porosities and aspects were fabricated.

As

optimization

fabricated

porosities


Input: The strength tended to increase with increasing E. Then, the structures were re-designed using shape optimization based on the traction method, targeting a simultaneous increase in yield strength with retention of the low E. The shapes were optimized through minimization of the maximum local von Mises stress and control of E to 3/2 or 2/3 of the original value, while maintaining constant porosity.

strength

yield strength

von Mises stress

porosity

optimization


Input: The re-designed cellular structures were fabricated and subjected to mechanical testing.

cellular structures

fabricated

mechanical testing


Input: The E values of the porous structures were comparable to the design values, but the strength of the cellular lattice with E = 2/3 (design value) was lower than expected.

porous

strength

design

design

lattice


Input: This discrepancy was attributed to inhomogeneities in the microstructures and their impact on the lattice mechanical properties.

microstructures

impact

lattice

properties


Input: Thus, shape optimization considering crystal orientation is a significant challenge for future research, but this approach has considerable potential.

optimization

research

crystal orientation


Input: A 3D finite element modelling of the SLM process at the track scale is considered.

process

element

SLM


Input: Heat transfer and fluid flow are simulated for different material and process conditions.

Heat transfer

process

fluid flow

material


Input: Scan speed, laser interaction and Marangoni effect have a clear impact on track shape.

Scan speed

laser

impact


Input: The present study is based on a formerly developed 3D finite element modelling of the selective laser melting process (SLM) at the track scale.

element

selective laser melting process

SLM


Input: This numerical model is used to assess the impact of two phenomena on the shape of the elementary track resulting from SLM processing: laser interaction on one hand, and Marangoni effect on the other hand.

model

impact

SLM

laser


Input: As regards laser interaction, it is modelled by a Beer-Lambert type heat source, in which lateral scattering and material absorption are considered through two characteristic parameters.

As

material

laser

heat source

absorption

parameters


Input: The impact of these parameters is shown in terms of width and depth of melted zone.

impact

parameters

melted


Input: The Marangoni effect caused by tangential gradients of surface tension is modelled to simulate the fluid dynamics in the melt pool.

surface tension

fluid

melt pool


Input: The resulting convection flow is demonstrated with surface tension values either increasing or decreasing with temperature.

surface tension

temperature


Input: The influence of energy distribution, surface tension effects, as well as laser scanning speed on temperature distribution and melt pool geometry is investigated.

distribution

distribution

geometry

surface tension

as

as

melt pool

scanning speed

temperature


Input: The stability and regularity of the solidified track are a direct output of the simulations, and their variations with material and process conditions are discussed.

stability

simulations

variations

process

material


Input: A three-dimensional finite element model is developed to allow for the prediction of temperature, residual stress, and distortion in multi-layer Laser Powder-Bed Fusion builds.

three-dimensional

finite element model

prediction

distortion

Fusion

temperature

residual stress

Laser

builds


Input: Undesirable residual stress and distortion caused by thermal gradients are a common source of failure in AM builds.

residual stress

distortion

failure

thermal gradients

source

AM


Input: A non-linear thermoelastoplastic model is combined with an element coarsening strategy in order to simulate the thermal and mechanical response of a significant volume of deposited material (38 layers and 91 mm3).

model

mechanical response

volume

element

material


Input: It is found that newly deposited layers experience the greatest amount of tensile stress, while layers beneath are forced into compressive stress.

deposited layers

tensile stress

compressive stress


Input: The residual stress evolution drives the mechanical response of the workpiece.

residual stress

evolution

mechanical response

workpiece


Input: The model is validated by comparing the predicted in situ and post process distortion to experimental measurements taken on the same geometry.

model

predicted

in situ

process distortion

experimental

geometry


Input: The model accurately predicts the distortion of the workpiece (5% error).

model accurately

distortion

workpiece

error


Input: This paper presents the first report on the development of weak-textured microstructures and resulting reduced in-plane anisotropy of mechanical properties in commercially pure titanium (CP-Ti) fabricated by electron beam melting (EBM).

microstructures

titanium

anisotropy

mechanical properties

fabricated

electron beam melting

EBM


Input: The as-built specimens exhibited fine grain structures with weakened crystallographic textures.

grain structures


Input: The β → α′ martensitic transformation after solidification was responsible for the weak textures as well as the relatively high strength.

solidification

as

as

strength


Input: The results suggest that it is possible to use EBM to produce isotropic CP-Ti components, which can not be obtained by conventional processes.

EBM

isotropic

components

be

processes


Input: In laser powder bed fusion (LPBF) the surface layer temperature is continually changing throughout the build process.

laser powder bed fusion

LPBF

surface

layer

build


Input: Variations in part geometry, scanned cross-section and number of parts all influence the thermal field within a build.

Variations

geometry

build


Input: Process parameters do not take these variations into account and this can result in increased porosity and differences in local microstructure and mechanical properties, undermining confidence in the structural integrity of a part.

Process parameters

variations

microstructure

mechanical properties

porosity

structural integrity


Input: In this paper a wide-field in situ infra-red imaging system is developed and calibrated to enable measurement of both solid and powder surface temperatures across the full powder bed.

in situ

calibrated

imaging

measurement

powder

temperatures

powder bed


Input: The influence of inter-layer cooling time is investigated using a build scenario with cylindrical components of differing heights.

cooling

build

cylindrical

components


Input: In situ surface temperature data are acquired throughout the build process and are compared to results from porosity, microstructure and mechanical property investigations.

In situ

data

microstructure

mechanical property

temperature

build

porosity


Input: Changes in surface temperature of up to 200 °C are attributed to variation in inter-layer cooling time and this is found to correlate with density and grain structure changes in the part.

surface

variation

grain structure

cooling

density


Input: This work shows that these changes are significant and must be accounted for to improve the consistency and structural integrity of LPBF components.

be

consistency

structural integrity

LPBF

components


Input: A three-dimensional model was developed for studying thermal behavior during selective laser melting (SLM) of commercially pure titanium (CP Ti) powder.

three-dimensional model

selective laser melting

SLM

titanium

Ti

powder


Input: The effects of scan speed and laser power on SLM thermal behavior were investigated.

scan speed

laser power

SLM


Input: The results showed that the average temperature of the powder bed gradually increased during the SLM process, caused by a heat accumulation effect.

average

process

powder bed

SLM

heat accumulation


Input: The maximum molten pool temperature (2248 °C) and liquid lifetime (1.47 ms) were obtained for a successful SLM process for a laser power of 150 W and a laser scan speed of 100 mm/s.

molten pool

process

SLM

laser power

laser scan


Input: The temperature gradient in the molten pool increased slightly (from 1.03 × 104 to 1.07 × 104 °C/mm in the direction perpendicular to the scanning path; from 1.21 × 104 to 1.28 × 104 °C/mm in the thickness direction) when the scan speed was increased from 50 to 200 mm/s, but increased significantly (from 1.29 × 104 to 8.24 × 104 °C/mm in the direction perpendicular to the scanning path; from 1.53 × 104 to 9.84 × 104 °C/mm in the thickness direction) when the laser power was increased from 100 to 200 W. The width and depth of the molten pool decreased (width from 137.1 to 93.8 μm, depth from 64.2 to 38.5 μm) when the scan speed was increased from 50 to 200 mm/s, but increased (width from 71.2 to 141.4 μm, depth from 32.7 to 67.3 μm) when the laser power was increased from 100 to 200 W. Experimental SLM of CP Ti powder was carried out under different laser processing conditions and the microstructure of SLM-produced parts was investigated to demonstrate the reliability of the physical model and simulation results.

temperature gradient

scan speed

laser power

scan speed

laser power

molten pool

scanning

scanning

molten pool

Experimental

laser processing

microstructure

physical model

Ti powder

reliability

simulation


Input: Rational design of experiment is employed to optimize the contour parameters to improve surface finish of inclined surfaces.

design of experiment

surfaces

contour

surface finish


Input: A significant variance in surface roughness is found among samples made at opposite corners on the build platform.

surface roughness

samples

build platform


Input: The recoating process sorts powder by size, smaller particles settle within a short distance from start position of recoater.

process

particles

powder


Input: Large particles ejected from melt pool can not be completely removed by inert gas flow and affect subsequent SLM process.

particles

inert gas

process

melt pool

be

SLM


Input: At a given position, inclined surface build up and away from the centre of the build platform has higher surface roughness.

surface

build

build platform

surface roughness


Input: A rational design of experiments was employed to evaluate the correlation between scan parameters and the resulting surface roughness of Selective Laser Melted Ti-6Al-4V components.

design of experiments

parameters

surface roughness

Selective Laser Melted

components


Input: There is a statistically significant difference in surface roughness values from specimens built with identical laser exposure parameters but located at different positions on the build platform.

surface roughness

laser

exposure

build platform


Input: We hypothesise that this is a consequence of changing powder particle size distributions across the powder bed resulting from the combined actions of the recoater arm and gas flow.

powder particle

distributions

gas

powder bed


Input: We further hypothesise that orientation of a part and the projected shape of the incident laser beam play a part in surface roughness variation at any given location.

orientation

laser beam

surface roughness


Input: We found that during the powder re-coating process, fine particles tend to settle within a short distance from the re-coater starting position, accompanied by higher variability of local powder size distribution.

powder

powder

process

particles

variability

distribution


Input: Spatter material was found to be distributed across the powder bed by the gas flow.

Spatter

material

be

powder bed

gas


Input: However, once at any given location the surface roughness of inclined surfaces is affected by the orientation of the surface to the centre of the build platform at which the laser beam originates.

surface roughness

surfaces

orientation

surface

laser beam

build platform


Input: Each of these factors affects the surface roughness and has implications for the order in which parts are built in Selective Laser Melting.

surface roughness

Selective Laser Melting


Input: Selective laser melting (SLM) is one of the most commonly used metallic component 3D printing techniques.

Selective laser melting

SLM

3D printing

metallic

component


Input: In a previous investigation of multiple materials SLM reported by The University of Manchester, high porosities and cracks were found in the regions where the powder was deposited via an ultrasonic powder dispenser.

materials

porosities

powder

powder


Input: The low powder packing density was identified as a critical reason for this.

powder

as

density


Input: In this paper, we report a new method to compress the ultrasonically deposited powder layer in order to increase the powder packing density.

powder

powder

layer

density


Input: The effects of powder deposition velocity, powder track overlap distance and powder compression force on the deposited powder characteristics were investigated.

powder

powder

powder

powder

deposition

overlap

compression


Input: The microstructure, tensile strengths, and porosity of the laser-fused samples were analyzed.

microstructure

samples

tensile strengths

porosity


Input: The results indicated that powder compression could reduce porosity and component distortion and increase the mechanical strength of the printed parts.

powder

compression

porosity

mechanical strength

component


Input: Heterogeneous materials used in biomedical, structural and electronics applications contain a high fraction of solids (> 60 vol.%) and exhibit extremely high viscosities (μ > 1000 Pa s), which hinders their 3D printing using existing technologies.

Heterogeneous

electronics

fraction

technologies

biomedical

Pa

3D printing


Input: This study shows that inducing high-amplitude ultrasonic vibrations within a nozzle imparts sufficient inertial forces to these materials to drastically reduce effective wall friction and flow stresses, enabling their 3D printing with moderate back pressures (< 1 MPa) at high rates and with precise flow control.

ultrasonic vibrations

nozzle

forces

materials

friction

pressures

MPa

flow stresses

3D printing


Input: This effect is utilized to demonstrate the printing of a commercial polymer clay, an aluminum-polymer composite and a stiffened fondant with viscosities up to 14,000 Pa·s with minimal residual porosity at rates comparable to thermoplastic extrusion.

polymer clay

composite

thermoplastic

residual

porosity

extrusion


Input: This new method can significantly extend the type of materials that can be printed to produce functional parts without relying on special shear/thermal thinning formulations or solvents to lower viscosity of the plasticizing component.

materials

be

viscosity

component


Input: The high yield strength of the printed material also allows freeform 3D fabrication with minimal need for supports.

yield strength

material

freeform 3D

fabrication

supports


Input: A self-healing and recyclable polyurethane based on dynamic halogenated bisphenol carbamate bonds was developed.

recyclable

dynamic

polyurethane


Input: The dynamic crosslinked polyurethane powders was developed for selective laser sintering for the first time.

dynamic

polyurethane

selective laser sintering


Input: The introduction of dynamic bonds enhances interface interaction and Z-direction mechanical strength of printed products.

dynamic

interface

Z-direction

mechanical strength


Input: Selective laser sintering (SLS) is one of the mainstream 3D printing technologies.

Selective laser sintering

SLS

3D printing technologies


Input: A major challenge for SLS technology is the lack of novel polymer powder materials with improved Z-direction strength.

SLS

polymer

materials

Z-direction

strength


Input: Herein, a dynamic polymer was utilized to solve the challenge of SLS.

dynamic

SLS


Input: The obtained dynamic polyurethane exhibited excellent mechanical strength and self-healing efficiency, in addition to SLS processing ability.

dynamic

mechanical strength

SLS


Input: A small molecule model study confirmed the dynamic reversible characteristics of the chlorinated bisphenol carbamate, which dissociates into isocyanate and hydroxyl at 120 °C and reforms at 80 °C, as confirmed by NMR and FT-IR.

model

dynamic

as

NMR

FT-IR


Input: SLS 3D printing using the self-made healable PBP-PU powders was successfully realized.

SLS

3D printing

powders


Input: The interface interaction between the adjacent SLS layers can be significantly improved via dynamic chemical bond linking instead of traditional physical entanglement, which leads to an improved Z-direction mechanical strength.

interface

dynamic

SLS

be

Z-direction

mechanical strength


Input: The SLS processed PBP-PU sample exhibits an X-axis tensile strengths of ∼23 MPa and an elongation at break of ∼600%.

SLS processed

sample

MPa

tensile strengths

elongation


Input: The Z-axis tensile strength is ∼88% of X-axis’ s, much higher than that of control TPU sample (∼56%).

Z-axis

sample

tensile strength

s


Input: High porosity and interconnected pore size are crucial factors for bone scaffolds.

porosity

pore size

bone scaffolds


Input: However, since porosity is inversely related to strength, the microstructure must be optimized to achieve bone scaffolds suitable for load-bearing applications.

porosity

strength

microstructure

be

bone scaffolds

load-bearing


Input: The powder bed 3D printing method can fabricate the highly porous parts possessing the desired properties using micron-sized ceramic powders (> 30 μm) and polymeric ink, however, low sinterability and, consequently, low strength is still a problem.

powder bed 3D printing method

fabricate

porous

sinterability

strength

properties

ceramic powders

polymeric ink


Input: In this study, nano-scale powders are granulated and printed by a special 3D printing method called ‘solvent jetting on granulated feedstock containing binder’ to achieve an interconnected macropore structure with high strength.

nano-scale powders

feedstock

binder

3D printing

solvent jetting

macropore structure

strength


Input: The advantages of this method, aside from the above mentioned, include obtaining controllable porosity, high strut density, wide neck formation, and small grain size; all of which are beneficial to mechanical strength.

porosity

density

grain size

mechanical strength

strut

wide neck formation


Input: Using this method, a purely ceramic sample with 30% porosity and compressive strength of 113.1 MPa was obtained.

ceramic

porosity

compressive strength

MPa


Input: Furthermore, a bone scaffold prototype with total porosity of nearly 50% and mechanical strength of 30.2 MPa was fabricated.

bone scaffold prototype

porosity

mechanical strength

MPa

fabricated


Input: These procedures and results are described and compared to another solvent jetting method which uses micron-sized powders.

solvent jetting

micron-sized powders


Input: The use of porous cellular structures in bone tissue engineering can provide mechanical and biological environments closer to the host bone.

porous

cellular structures

bone

host bone

engineering

mechanical


Input: However, poor internal architectural designs may lead to catastrophic failure.

designs

lead

failure


Input: In this work, 192 open-porous cellular structures were fabricated using 3D printing (3DP) techniques.

cellular structures

fabricated

3D printing


Input: It was found that the pillar octahedral shape has not only greater stiffness and strength under compression, shear and torsion but increased rate of pre-osteoblastic cell proliferation.

stiffness

strength

compression

cell


Input: We believe bone implants can be fabricated using 3DP techniques and their mechanical and biological performance can be tailored by modifying the internal architectures.

bone implants

mechanical

be

be

performance

internal architectures


Input: Vat photopolymerization is used for printing very precise and accurate parts from photopolymer resins.

Vat photopolymerization

accurate

photopolymer resins


Input: Conventional 3D-printers based on vat photopolymerization are curing resins with low viscosity at or slightly above room temperature.

vat photopolymerization

curing

viscosity

temperature


Input: The newly developed Hot Lithography provides vat photopolymerization where the resin is heated and cured at elevated temperatures.

Lithography

vat photopolymerization

cured

resin

temperatures


Input: This study presents the influence of printing temperature (23 °C and 70 °C) on the properties of a printed dimethacrylate resin.

temperature

properties

resin


Input: Specimens were printed in XYZ and ZXY orientation.

orientation


Input: The resulting tensile properties were tested, dynamic mechanical analysis was carried out and the double-bond conversion was analyzed.

tensile properties

dynamic mechanical analysis


Input: Therefore, the exposure time was reduced from 50 s to 30 s to reach similar curing depth.

exposure

s

s

curing depth


Input: Higher printing temperature provided higher double-bond conversion, tensile strength and modulus of the green parts.

temperature

tensile strength

green parts


Input: However, printing temperature did not affect the properties after post-curing in XYZ orientation.

temperature

properties

orientation


Input: Post-cured tensile specimens in ZXY orientation had higher tensile strength when printed at 23 °C, because higher over-polymerization led to a smoother surface of the specimens.

tensile specimens

orientation

surface

tensile strength

led


Input: Overall, higher printing temperatures lowered the viscosity of the resin, reduced the printing time and provided better mechanical properties of green parts while post-cured properties were mostly not affected.

temperatures

viscosity

green parts

resin

mechanical properties

properties


Input: In laser powder bed fusion, melt pool dynamics and stability are driven by the temperature field in the melt pool.

laser powder bed fusion

melt pool

melt pool

stability

temperature


Input: If the temperature field is unfavourable defects are likely to form.

temperature

defects


Input: The localised and rapid heating and cooling in the process presents a challenge for the experimental methods used to measure temperature.

heating

cooling

process

experimental

temperature


Input: As a result, understanding of these process fundamentals is limited.

As

process


Input: In this paper a method is developed that uses coaxial imaging with high-speed cameras to give both the spatial and temporal resolution necessary to resolve the surface temperature of the melt pool.

imaging

resolution

surface

melt pool


Input: A two wavelength imaging setup is used to account for changes in emissivity.

wavelength

imaging


Input: Temperature fields are captured at 100 kHz with a resolution of 20 μm during the processing of a simple Ti6Al4V component.

Temperature

resolution

simple

component


Input: Thermal gradients in the range 5–20 K/μm and cooling rates in range 1–40 K/μs are measured.

Thermal gradients

range

cooling rates

range


Input: The results presented give new insight into the effect of parameters, geometry and scan path on the melt pool temperature and cooling rates.

parameters

geometry

melt pool

cooling rates


Input: The method developed here provides a new tool to assist in optimising scan strategies and parameters, identifying the causes of defect prone locations and controlling cooling rates for local microstructure development.

tool

parameters

defect

microstructure

cooling rates


Input: In laser directed energy deposition (L-DED) processes, by applying a converged powder stream, relatively high laser power and larger laser spot, the powder utilisation efficiency and processing speed can be increased.

laser directed energy deposition

processes

powder

powder

be

laser power

laser


Input: In this paper, a three-dimensional numerical model is established to study the mass transport and heat transfer in the melt pools in high deposition rate (HDR) L-DED of 316L stainless steel.

three-dimensional

model

heat transfer

transport

melt pools

316L stainless steel

high deposition rate


Input: The Volume of Fluid (VOF) method is employed to track the melt pool free surfaces, and enthalpy-porosity method is used to model the solid-liquid phase change.

Volume of Fluid

VOF

free surfaces

model

phase

melt pool


Input: A discrete powder source model is developed by considering the non-uniform powder feed rate distribution.

powder

powder

model

distribution

feed


Input: Different from conventional L-DED processes, the impact of higher mass addition on the melt pool fluid flow and temperature distribution is significant.

processes

impact

distribution

melt pool

fluid flow

temperature


Input: With the extracted temperature distribution and geometry at the solidification front, the solidification conditions are also calculated, as well as the primary dendrite arm spacing (PDAS) of the solidified tracks.

extracted

distribution

geometry

solidification

solidification

as

as

dendrite


Input: Due to the high laser energy input, the temperature gradient is lower, and coarser microstructures are formed compared with conventional L-DED.

laser energy

temperature gradient

microstructures


Input: A single-photon absorption 3D stereolithographic methodology is presented.

absorption 3D

methodology


Input: Meso-scale architectures can be achieved with 5 μm resolution along (x, y, z).

be

y

resolution


Input: Process parameters (e.g.

Process parameters


Input: exposure, slicing) adaptable to each region of the 3D design.

exposure

slicing


Input: 3D printing of highly complex porous architectures featuring overhanging units.

3D printing

porous


Input: The realization of 2D and 3D meso-scale architectures is an area of research involving a wide range of disciplines ranging from materials science, microelectronics, phononics, microfluidics to biomedicine requiring millimeter to centimeter-sized objects embedding micrometric features.

research

materials

microelectronics

microfluidics

area

range

biomedicine


Input: In the recent years, several technologies have been employed to provide optimal features in terms of object size flexibility, printing resolution, large materials library and fabrication speed.

technologies

materials

flexibility

resolution

fabrication


Input: In this work, we report a fully customizable single-photon absorption 3D fabrication methodology based on direct laser fabrication.

absorption 3D

methodology

laser

fabrication


Input: To validate this approach and highlight the versatility of the setup, we have fabricated a comprehensive ensemble of 2D and 3D designs with potential applications in biomimetics, 3D scaffolding and microfluidics.

fabricated

biomimetics

microfluidics


Input: The high degree of tunability of the reported fabrication system allows tailoring the laser power, slicing and fabrication speed for each single area of the design.

fabrication

fabrication

laser power

area

slicing

design


Input: These unique features enable a rapid prototyping of millimeter to centimeter-sized objects involving 3D architectures with true freestanding subunits and micrometric feature reproducibility.

rapid prototyping

feature


Input: This study focuses on the microstructure evolution induced by eutectic WC-W2C inoculants during the selective laser melting (SLM) of IN718.

microstructure evolution

eutectic

selective laser melting

SLM


Input: The as-built microstructure observed using an electron microscope indicates that grain nucleation occurred on the surface of inoculants and that the diffusion layer between inoculants and IN718 composed of a mixture of IN718 and inoculants.

microstructure

grain

surface

diffusion

microscope


Input: After the post heat treatment of the as-built SLM specimens, more grains nucleated around the inoculants, and Nb-rich precipitates were formed along the grain boundaries.

heat treatment

SLM

grains

grain boundaries

precipitates


Input: With an increase in the post heat-treatment temperature, the microstructure evolution became more pronounced.

post heat-treatment

microstructure evolution


Input: To elucidate the underlying mechanism, both theoretical and experimental analyses were performed.

mechanism

theoretical

experimental


Input: In summary, eutectic WC-W2C inoculants could provide heterogeneous nucleation sites for grain formation owing to the low wetting angle and the semi-coherent interface with the matrix.

eutectic

heterogeneous nucleation

grain

interface


Input: Theoretical analysis suggests that the difference in the thermal expansion coefficient between inoculants and IN718 did not provide a significant amount of residual stress.

Theoretical

thermal expansion coefficient

residual stress


Input: Thus, it can be concluded that heterogeneous nucleation is the primary mechanism by which inoculants can influence the microstructure in the present study.

be

heterogeneous nucleation

mechanism

microstructure


Input: This paper presents an integrated physics-based and statistical modeling approach to predict temperature field and meltpool geometry in multi-track processing of laser powder bed fusion (L-PBF) of nickel 625 alloy.

modeling

temperature

meltpool

geometry

laser powder bed fusion

L-PBF

nickel

alloy


Input: Multi-track laser processing of powder material using L-PBF process has been studied using 2-D finite element simulations to calculate temperature fields along the scan and hatch directions for three consecutive tracks for a moving laser heat source to understand the heating and melting process.

laser processing

finite element

powder material

L-PBF

heating

melting

temperature

laser heat


Input: Based on the predicted temperature fields, width, depth and shape of the meltpool is determined.

predicted

meltpool


Input: Designed experiments on L-PBF of nickel alloy 625 powder material are conducted to measure the relative density and meltpool geometry.

Designed

L-PBF

nickel alloy

powder material

relative density

meltpool

geometry


Input: Experimental work is reported on the measured density of built coupons and meltpool size.

Experimental

density

meltpool


Input: Statistically-based predictive models using response surface regression for relative density, meltpool geometry, peak temperature, and time above melting point are developed and multi-objective optimization studies are conducted by using genetic algorithm and swarm intelligence.

predictive models

surface

regression

geometry

optimization

genetic algorithm

relative density

melting point

meltpool

temperature


Input: A fragile and non-thixotropic biocompatible low molecular weight gel is printed in 3D structures by a solvent exchange process.

fragile

3D structures

solvent exchange

process

non-thixotropic biocompatible

low molecular weight gel


Input: The 3D printing process is based on the continuous extrusion of a solution of a small amphiphile molecule, N-heptyl-d-galactonamide, in dimethylsulfoxide, that forms a gel in contact with water.

3D printing

extrusion

solution

amphiphile

N-heptyl-d-galactonamide

dimethylsulfoxide

gel

contact


Input: The diffusion of water in the dimethylsulfoxide/N-heptyl-d-galactonamide solution triggers the self-assembly of the molecule into supramolecular fibers and the setting of the ink.

diffusion

self-assembly

dimethylsulfoxide

N-heptyl-d-galactonamide

supramolecular fibers

ink


Input: The conditions for getting a well-defined pattern and the dimensions of the constructs have been determined.

pattern

dimensions


Input: The resulting constructs can be easily dissolved, orienting its application as a sacrificial ink or a temporary support.

be

as

sacrificial ink

support


Input: This method opens the way to the injection and the 3D printing of other fragile and non-thixotropic supramolecular hydrogels.

3D printing

fragile

non-thixotropic

hydrogels


Input: Biofabrication is the process of transforming materials into systems that reproduce biological structure and function.

Biofabrication

process

materials

biological structure


Input: Previous attempts to create biomimetic systems have often used single materials shaped into limited configurations that do not mimic the heterogeneous structure and properties of many biological tissues.

biomimetic

materials

heterogeneous

properties

mimic

biological tissues


Input: The printer was used to fabricate a range of composite materials containing varying blends of a tough alginate/poly (acrylamide) ionic covalent entanglement hydrogel and an acrylated urethane based UV-curable adhesive material.

printer

fabricate

range

composite materials

blends

hydrogel

urethane

adhesive


Input: The hard adhesive material acted as particulate reinforcement within the matrix of composites printed with a large hydrogel volume fraction.

adhesive

as

composites

hydrogel

reinforcement

fraction


Input: The composite materials were characterized mechanically and their performance could be modeled with standard composite theory.

composite materials

be

composite

performance

standard


Input: The platform of a 3D printer allowed these composite materials to be fabricated directly with a smooth and continuous gradient of modulus between the soft hydrogel and harder acrylated urethane material, which may be useful in the development of bio-inspired structures such as artificial tendons.

platform

3D printer

composite materials

be

hydrogel

urethane material

be

as

bio-inspired structures


Input: This work investigated the utility of three piezoelectric inkjet printers as energetic material deposition systems, focusing on the ability of each system to achieve the seamless integration of energetic material into small-scale electronic devices.

inkjet

as

material

material

deposition


Input: Aluminum copper (II) oxide nanothermite was deposited using the three deposition systems.

Aluminum

oxide

deposition


Input: The printers were evaluated based on their robustness to energetic ink solids loading, drop formation reliability, drop quality degradation over time, and the energetic performance of the deposited material.

printers

robustness

ink

material

reliability

quality degradation

performance


Input: These metrics correlate to the feasibility of a deposition system to successfully achieve high sample throughput while maintaining the energetic performance of the printed material.

feasibility

deposition

sample

performance

material


Input: After initial system testing, the PipeJet P9 500 μm pipe was used to demonstrate the successful deposition of nanothermite in varying geometric patterns with micrometer precision.

testing

deposition

micrometer


Input: Popular 3D printing techniques such as fused deposition modelling (FDM) and stereolithography (SLA) have certain limitations and challenges.

3D printing

FDM

stereolithography

as

deposition

SLA


Input: Although printing multi-material functional parts combining smart and conventional materials is a promising area, existing printers are not ideally suited to this, with FDM printers typically requiring high operating temperatures and SLA using a tank containing one single material.

multi-material

materials

area

temperatures

printers

FDM printers

SLA

material


Input: Common 3D printers also require the deposition of additional “support” material to hold the shape of an object when printing overhang structures.

3D printers

deposition

support

material

overhang


Input: The concept of adding additional rotational axes to the system to eliminate this problem has shown promising results, but such systems still lack the capability to print complex structures without supports.

print

complex structures

supports


Input: To overcome these limitations there is a need to develop a new 3D printing techniques that combine the strengths of existing methods.

3D printing

strengths


Input: A photopolymer extrusion 3D printing technique, which combines the strengths of FDM and UV assisted 3D printing technology is demonstrated in this paper.

photopolymer

extrusion

3D printing

FDM

strengths

UV

3D printing technology


Input: By using photopolymer extrusion in combination with two additional rotational axes, the printer developed in this work not only allows the traditional layer upon layer printing, but is also capable of free form printing.

photopolymer

extrusion

printer

layer

layer


Input: Fumed silica is used as a filler in order to control the material viscosity for proper extrusion and curing.

silica

as

material

extrusion

curing


Input: Mechanical tests were conducted on objects printed using different concentrations of filler in the photopolymer to understand its effect and determine the range of suitable filler concentration.

Mechanical tests

photopolymer

range


Input: Multilayer HSS alloys have been produced by laser cladding and characterized in terms of their microstructural evolution, hardness, stress state and tensile properties.

HSS

alloys

laser cladding

microstructural evolution

hardness

stress

tensile properties


Input: Massive martensitic transformation during cladding of HSS alloys, resulted in the compressive state of clads and suppressed the cracking.

cladding

HSS

alloys

cracking


Input: Re-heating during laser cladding of thick multilayer coatings of an Fe-Cr-Mo-W-V alloy had a detrimental effect on the hardness of intermediate layers.

laser cladding

coatings

alloy

hardness


Input: Addition of Co in LC1 at the expense of Fe (Fe−x-Cr-Mo-W-V-Cox) significantly increased the overall coating hardness by strengthen the matrix.

Co

Fe

coating


Input: Tensile testing results showed a strong adherence of thick multilayer coatings with the substrate.

Tensile testing

coatings

substrate


Input: Two high speed steel (HSS) alloys were laser cladded on 42CrMo4 steel cylindrical substrate by using a 4 kW Nd: YAG laser source.

high speed steel

HSS

alloys

steel

Nd: YAG

laser

cylindrical

laser source


Input: After optimization of the laser material processing parameters for single layers, multilayered clads were produced.

optimization

parameters

laser


Input: Microstructural characterization of the laser deposits constitutes studies of the carbides and matrix, which was done by using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Electron Backscattered Diffraction (EBSD) and High Resolution Transmission Electron Microscopy (HRTEM) .The strengthening mechanism of LC1 (Fe-Cr-Mo-W-V) was comprised of a martensitic matrix and retained austenite along with networks of VC and Mo2C eutectic carbides.

Microstructural characterization

Scanning Electron Microscopy

SEM

Energy Dispersive Spectroscopy

EDS

Diffraction

EBSD

High Resolution Transmission Electron Microscopy

HRTEM

laser

carbides

retained austenite

VC

carbides

strengthening mechanism

eutectic


Input: Cr enriched fine carbides (Cr7C3 and Cr23C6) were embedded within the matrix.

Cr

carbides


Input: During laser cladding of the multilayer deposits, cladding of subsequent layers had a detrimental effect on the hardness of previously cladded layers, which was due to tempering of existing lath martensite.

laser cladding

cladding

tempering

hardness

martensite


Input: To overcome the hardness drop, a new alloy LC2 (Febal−x-Cr-Mo-W-V-Cox) was blended by addition of 3–5% of Co in LC1.

hardness

alloy

Co


Input: The addition of Co resulted in an overall increase in hardness and a reduction in the hardness drop during sequential layer cladding; the latter was due to the presence of Co in the solid solution with Fe.HRTEM was performed to characterize the nanometer-sized precipitates evolved during the re-heating.

Co

Co

solid solution

precipitates

hardness

hardness

reduction

layer

cladding


Input: These carbides were either enriched with V and W or formed from a complex combination of V, Mo, W and Cr with lattice spacings of 0.15 nm to 0.26 nm.

carbides

V

V

Mo

Cr

lattice


Input: An urgent need in the laser powder bed fusion (LPBF) process is to efficiently remove emissions from or around the moving melt pool since the powder bed contamination by spatter can potentially damage fabricated part quality.

laser powder bed fusion

LPBF

process

quality

melt pool

powder bed

spatter

damage


Input: The objective of this study is to propose new designs of the gas flow system in the build chamber to enhance the removability of spatter.

designs

gas

build chamber

spatter


Input: Specifically, a Computational Fluid Dynamics (CFD) model for the LPBF gas flow system has been developed to simulate the complicated flow behavior inside the build chamber.

Computational Fluid Dynamics

CFD

model

gas

LPBF

build chamber


Input: The movement of spatter has been calculated by the Discrete Phase Model (DPM).

spatter

Phase Model


Input: The fully coupled CFD-DPM fluid-particle interaction method has been applied to capture the influence of gas flow on solid particles accurately.

gas

particles

accurately


Input: Additionally, an analytical expression is utilized to obtain the threshold velocity of inert gas flow upon the powder bed.

inert gas

powder bed


Input: The spatter distribution in a generic gas chamber design was studied.

spatter

distribution

gas

design


Input: It was found that the Coanda effect, a gas flow downward tendency toward the substrate, can have a significant impact on the spatter removal process.

gas

impact

process

substrate

spatter


Input: With the proposed new designs, the Coanda effect is minimized, and most of the spatters can be removed from the build region without blowing up powder bed particles.

designs

be

build

blowing

powder bed

particles


Input: Polymer extrusion three dimensional (3D) printing, such as fused deposition modeling (FDM), has recently garnered attention due to its inherent process flexibility and rapid prototyping capability.

Polymer extrusion

FDM

deposition modeling

process

as

flexibility

rapid prototyping


Input: Specifically, the addition of electrical components and interconnects into a 3D printing build sequence has received heavy interest for space applications.

electrical

components

3D printing


Input: However, the addition of these components, along with the thermal load associated with space-based applications, may prove problematic for typical thermally insulating 3D printed polymer structures.

components

insulating

3D printed


Input: The work presented here addresses thermally conductive polymer matrix composites (specifically, graphite, carbon fiber, and silver in an acrylonitrile butadiene styrene polymer matrix) to identify the effect of composite geometry and print direction on thermal anisotropic properties.

polymer matrix composites

graphite

carbon fiber

silver

acrylonitrile butadiene styrene

composite

print

anisotropic


Input: The work also examines the effect of these composites on print quality, mechanical tensile properties, fracture plane analysis, micrograph imaging, and cube satellite thermal analysis.

composites

print quality

properties

fracture

cube

mechanical

imaging

thermal analysis


Input: The thermal conductivity of 3D printed material systems in this work may enable the production of thermally stable 3D printed structures, supports, and devices.

thermal conductivity

3D printed

production

3D printed

supports


Input: Key results of this work include anisotropic thermal conductivity for 3D printed structures related to print direction and filler morphology meaning that thermal conductivity can be controlled through a combination of print raster direction and material design.

anisotropic

conductivity

thermal conductivity

3D printed

print

print

morphology

be

material

design


Input: When the materials analyzed in this work are incorporated with other active cooling systems, space-based 3D printed applications can then be designed to incorporate increasing thermal loads, opening a new door to producing space-ready 3D printed structures.

materials

cooling

3D printed

3D printed

be


Input: Inverse process embedded 3D printing multi internal surfaces hydrogel and application in anatomical organ model.

process

surfaces

model

embedded 3D printing

hydrogel


Input: Inverse process-based printing strategies can speed up 3D printing and increase efficiency.

3D printing


Input: Prepolymer has high transparency, and has shear thinning behavior and yield stress characteristics.

Prepolymer

shear thinning

yield stress


Input: The most current 3D printing method involves the combination of additional processes, such as casting and demolding, to produce an organ model.

3D printing

processes

demolding

model

as


Input: This method requires professionals to invest a considerable amount of time in editing the model and post-processing activities.

model

post-processing


Input: In this work, embedded three-dimensional printing (EMB3D) is performed in a transparent and photocrosslinkable support medium.

embedded three-dimensional printing

transparent

photocrosslinkable


Input: Based on a photo-curable hydrogel precursor with yield stress behavior, a new EMB3D printing strategy is developed, which could be considered as an inverse process.

photo-curable

hydrogel

be

as

yield stress

process


Input: During printing, a closed shell is formed with a release ink using a capillary needle.

shell

capillary needle

ink


Input: After printing, the support medium is photocrosslinked to a solid part, and the object is peeled off along with the closed shell.

support

photocrosslinked

shell


Input: The stated approach makes it possible to produce transparent and elastic solid objects with multi-internal surfaces.

transparent

surfaces

elastic


Input: Moreover, it can be applied in providing a soft, dissectible, accurate, and highly interactive model for medical doctors to facilitate surgical processes.

be

dissectible

model

surgical processes

accurate

medical


Input: A geometry-based model for predicting lack-of-fusion porosity is presented.

model

porosity


Input: The model relies on melt pool dimension, hatch spacing and layer thickness.

model

melt pool dimension

hatch spacing

layer thickness


Input: Porosity (or density) predicted with the model agrees well with reported literature data.

Porosity

density

predicted

model

data


Input: A geometry-based simulation is used to predict porosity caused by insufficient overlap of melt pools (lack of fusion) in powder bed fusion.

simulation

porosity

overlap

fusion

melt pools

powder bed fusion


Input: The inputs into the simulation are hatch spacing, layer thickness, and melt-pool cross-sectional area.

simulation

hatch spacing

layer thickness

area


Input: Melt-pool areas used in the simulations can be obtained from experiments, or estimated with the analytical Rosenthal equation.

areas

simulations

be

Rosenthal equation


Input: The necessary material constants, including absorptivity for laser-based melting, have been collated for alloy steels, aluminum alloys and titanium alloys.

material

alloy steels

aluminum alloys

titanium alloys

melting


Input: Comparison with several data sets from the literature shows that the simulations correctly predict process conditions at which lack-of-fusion porosity becomes apparent, as well as the rate at which porosity increases with changes in process conditions such as beam speed, layer thickness and hatch spacing.

data

process

process

simulations

porosity

porosity

as

as

as

layer thickness

hatch spacing


Input: To fabricate highly complex structures, sacrificial support material is usually needed.

fabricate

complex structures

support material


Input: However, traditional petroleum-based support materials are un-sustainable, non-recyclable, and difficult to be completely removed from the target structure after 3D processing.

petroleum-based

be

materials

un-sustainable

non-recyclable

structure

3D processing


Input: Instead, cellulose nanocrystals (CNC) gel could serves as an interesting 3D printing support material due to its sustainability, renewability, and potential recyclability.

cellulose nanocrystals

gel

as

material

CNC

3D printing

sustainability

renewability

recyclability


Input: Since CNCs are highly dispersible in water as nanoparticles and are also not UV sensitive, it has less absorption or bondability with other UV curable polymer matrices.

CNCs

as

UV curable polymer

UV

absorption

bondability


Input: This allows them to be completely washed out by water, which offers a green and efficient method to remove the CNC support material during post processing.

be

material

CNC

post processing


Input: In addition, with increasing needs for more intricate structures, combining different 3D printing strategies into a hybrid 3D printing platform can be highly beneficial.

3D printing

hybrid 3D printing

be


Input: In this work, a multi-materials-multi-methods (M4) printer with dual direct-ink-write (DIW) and DIW-inkjet printing capability was used to fabricate various complex structures while using CNC as support material.

multi-materials-multi-methods

complex structures

direct-ink-write

DIW

DIW-inkjet printing

fabricate

printer

CNC

as

material


Input: After 3D printing, water was used to remove the CNC support structure.

3D printing

CNC

structure


Input: Even in a highly confined environment, such as the inside of a balloon structure, CNC support material was still easily removed.

as

material

structure

CNC


Input: The potential of using sustainable CNC support material and M4 hybrid 3D printing strategies to fabricate different complex structures was demonstrated.

sustainable

complex structures

CNC

material

hybrid 3D printing

fabricate


Input: Since CNC gel is derived from forestry products and is entirely water based, the 3D printing process was also made more environmentally friendly, sustainable, and potentially recyclable.

CNC gel

3D printing

sustainable

recyclable


Input: Composite coatings of titanium reinforced separately with hydroxyapatite (HAp) and bioglass (BG) were deposited on titanium substrate using Laser Engineered Net Shaping (LENS™).

Composite coatings

titanium

hydroxyapatite

titanium substrate

reinforced

Laser Engineered Net Shaping


Input: The microstructure, phase constituents, in vitro electrochemical, tribological and biological properties of these composite coatings deposited using different laser powers was studied.

microstructure

phase

electrochemical

tribological

properties

composite coatings

laser powers


Input: The composite coatings showed several reaction products such as Ca2P2O7, CaTiO3, Na2Ca2Si3O9 due to high temperature interaction of HAp and BG with Ti.

composite coatings

as

Ti

temperature


Input: The average top surface hardness of the Ti substrate was 148 ± 5 HV and that of the composite coatings was between 720 and 740 HV.

average

surface

hardness

Ti substrate

composite coatings


Input: As a result, the composite coatings exhibited significant increase in the in vitro wear resistance.

As

composite coatings

wear resistance


Input: The incorporation of HAp and BG in Ti increased the corrosion current, possibly due to the presence of residual stresses, but shifted the corrosion potential towards noble direction due bioactive reinforcements.

Ti

corrosion

corrosion

residual stresses


Input: In vitro proliferation of mouse embryonic fibroblast cells (NIH3T3) was found to be more on composite coatings than on titanium substrate demonstrating their superior cell-materials interactions.

fibroblast

cells

be

composite coatings

titanium substrate


Input: One-photon or two photon absorption by dye molecules in photopolymers enable direct 2D & 3D lithography of micro/nano structures with high spatial resolution and can be used effectively in fabricating artificially structured nanomaterials.

absorption

photopolymers

be

nanomaterials

resolution

fabricating


Input: Complex 2D patterns and 3D meshes were fabricated with sub-micron resolution, in commercially available liquid photopolymer to show the impact/versatility of this technique.

2D patterns

sub-micron

fabricated

resolution

photopolymer


Input: Pure Al with high laser reflectivity is essentially incompatible with laser powder bed fusion.

Al

laser

laser powder bed fusion


Input: The retention of a large number of unmelted particles leads to inferior geometrical quality and mechanical properties of printed pure Al parts.

particles

quality

mechanical properties

Al


Input: In the present study, we propose decorating Al with a small amount of high laser absorbing Co nanoparticles on the surface of Al powders to reduce laser reflectivity and improve printability.

Al

Co

Al

laser

laser

surface

printability


Input: The near homogenous dispersion of Co slightly modified the surface chemical composition and roughened the powder surface.

dispersion

surface

chemical composition

Co

powder


Input: This approach completely melted the particles and eliminated the internal pores, thereby favorably tuning the geometrical dimensions.

melted

particles

pores

dimensions


Input: Additionally, the introduction of Co provided solid solution strengthening and precipitation hardening via dispersion of second-phase Al9Co2 with a coherent interfacial relationship with the Al matrix.

Co

solid solution

Al

precipitation hardening

dispersion


Input: The tensile properties of printed Al parts were comparable to commercial medium-strength Al alloys at an optimal Co-content of 0.5 wt.%.

tensile properties

Al

Al alloys


Input: Addition of Nb and Mo improved the UTS and elongation of L-PBF 420 stainless steel.

Nb

Mo

420 stainless steel

UTS

elongation

L-PBF


Input: Nanoscale NbC precipitated in the presence of Nb and Mo.

Nb

Mo


Input: Tempering of martensites and NbC correlated with improved mechanical properties.

Tempering

correlated

mechanical properties


Input: Mechanical and corrosion properties of L-PBF specimens were superior to wrought 420 stainless steel.

Mechanical

corrosion properties

L-PBF

wrought

420 stainless steel


Input: Niobium (Nb) and molybdenum (Mo) are conventionally added to stainless steels to improve their mechanical and corrosion properties.

Niobium

Nb

molybdenum

Mo

stainless steels

mechanical

corrosion properties


Input: However, the effects of Nb and Mo addition on the processing and properties in laser-powder bed fusion (L-PBF) have not been well investigated, especially in the context of 420 stainless steel.

Nb

Mo

420 stainless steel

properties

bed fusion

L-PBF


Input: In this study, 420 stainless steel pre-alloyed with Nb (1.2 wt.%) and Mo (0.57 wt.%) was processed by L-PBF and characterized in terms of its physical, mechanical and corrosion properties as well as microstructure.

420 stainless steel

Nb

Mo

as

as

processed

L-PBF

mechanical

corrosion properties


Input: The addition of Nb and Mo did not significantly affect the densification of 420 stainless steel when printed over an energy range of 28–75 J/mm3 and a maximum density of 99.3 ± 0.02% theoretical at 63 J/mm3 was achieved.

Nb

Mo

420 stainless steel

densification

range

density

theoretical


Input: In mechanical tests, L-PBF 420 stainless steel specimens exhibited higher mechanical properties in the presence of Nb and Mo.

mechanical tests

L-PBF

420 stainless steel

Nb

Mo

mechanical properties


Input: After heat treatment, the UTS of 420 stainless steel with Nb and Mo improved to 1750 ± 30 MPa and elongation to 9.0 ± 0.2%, much higher than previously reported properties achieved in L-PBF and exceeding wrought 420 stainless steel.

heat treatment

L-PBF

UTS

elongation

420 stainless steel

Nb

Mo

420 stainless steel

MPa

properties

wrought


Input: The tempering of martensite phases as well as the presence of nanoscale NbC were found to correlate with improved mechanical properties.

tempering

martensite

as

as

mechanical properties


Input: In electrochemical tests, 420 stainless steel exhibited slightly better corrosion properties with the addition of Nb and Mo.

electrochemical tests

420 stainless steel

Nb

Mo

corrosion properties


Input: Bagasse CNF inks are produced for 3D printing by direct-ink-writing technology.

Bagasse

3D printing

direct-ink-writing technology


Input: The CNF were found not to have a cytotoxic potential.

CNF

cytotoxic


Input: Alginate and Ca2+ caused significant structural changes to the 3D printed grid constructs.

Alginate

3D printed


Input: Ca2+ crosslinked constructs offer potential for personalized wound dressing devices.

wound dressing devices


Input: Sugarcane bagasse, an abundant residue, is usually burned as an energy source.

Sugarcane bagasse

residue

as

source


Input: However, provided that appropriate and sustainable pulping and fractionation processes are applied, bagasse can be utilized as a main source of cellulose nanofibrils (CNF).

sustainable

processes

bagasse

be

as

cellulose nanofibrils

CNF

source


Input: We explored in this study the production of CNF inks for 3D printing by direct-ink-writing technology.

production

3D printing

direct-ink-writing technology

CNF inks


Input: The CNF were tested against L929 fibroblasts cell line and we confirmed that the CNF from soda bagasse fibers were found not to have a cytotoxic potential.

CNF

L929 fibroblasts

CNF

soda bagasse fibers

cell

cytotoxic


Input: Additionally, we demonstrated that the alginate and Ca2+ caused significant dimensional changes to the 3D printed constructs.

alginate

3D printed constructs


Input: The CNF-alginate grids exhibited a lateral expansion after printing and then shrank due to the cross-linking with the Ca2+.

CNF-alginate

lateral expansion

cross-linking


Input: The release of Ca2+ from the CNF and CNF-alginate constructs was quantified thus providing more insight about the CNF as carrier for Ca2+.

CNF

CNF-alginate

CNF

as


Input: This, combined with 3D printing, offers potential for personalized wound dressing devices, i.e.

3D printing

wound dressing devices


Input: Herein, we developed a direct-write printing process capable of producing versatile biomimetic patterns with aligned neurites using multiple cell types.

printing process

biomimetic

cell


Input: After two weeks of differentiation, aligned neurites were induced by the contractile force of the printed cells.

force

cells


Input: Finally, we demonstrated the usefulness of the printing process by fabricating a Y-shaped branch and six-layered pattern.

printing process

fabricating

pattern


Input: The six-layered pattern mimicking cerebral cortex tissue was produced by precise printing of two different colored cells.

pattern

cells


Input: These results indicate that versatile biomimetic neural constructs composed of multiple cell types can be produced by our new direct-write printing process.

biomimetic

cell

be

printing process


Input: Electrets have been increasingly investigated for their high piezoelectric sensitivity for sensing and energy harvesting applications, but fabricating complex 3D structures for optimum performance has remained challenging.

Electrets

piezoelectric sensitivity

sensing

energy harvesting

3D structures

performance

fabricating


Input: 3D printing capabilities have likewise become a mature manufacturing technology widely used for end-user customization and rapid prototyping, but limitations on materials and geometries have complicated the incorporation of electroactive structures.

3D printing

manufacturing technology

rapid prototyping

materials

geometries

electroactive structures


Input: In this paper, the first completely 3D printed porous piezoelectret is demonstrated.

3D printed

piezoelectret


Input: These samples were structured using standard infill patterns commonly used in 3D printing, allowing easy incorporation with current 3D printing technology.

samples

standard

infill

3D printing

3D printing technology


Input: Pores generated by fused-filament fabrication (FFF) are characterized, charged, and the resultant piezoelectret activity measured.

Pores

fused-filament fabrication

FFF

piezoelectret


Input: Analytical electromechanical models are used to understand and compare the measured charge density and piezoelectric coefficients.

electromechanical models

piezoelectric coefficients

charge density


Input: The piezoelectric coefficient is found to increase strongly with decreasing infill percentages.

piezoelectric coefficient

infill percentages


Input: An average piezoelectric d33 coefficient of 87 pC N−1 is achieved for 5% infill samples and is found to be stable for a period of at least 2 weeks, competitive with many other state-of-the-art single-pore piezoelectretic materials.

average

state-of-the-art

pC

be

piezoelectretic materials

infill


Input: These results provide a first step in using 3D printing techniques to optimize and integrate piezoelectrets into parts, allowing a useful new electroactive functionality for additive manufacturing.

step

electroactive functionality

3D printing

additive manufacturing

piezoelectrets


Input: Three-dimensionally (3D) printed flexible piezoresistive composite sensors have provided valuable solutions for the personalized therapeutic development due to their promising capability in biomonitoring applications.

Three-dimensionally

therapeutic

piezoresistive composite sensors

biomonitoring applications


Input: Silicone rubber (SR) matrix is an important candidate to enable flexibility to the 3D printed devices.

Silicone rubber

SR

flexibility

3D printed


Input: However, 3D printing of silicone inks blended with conductive fillers is limited due to the high viscosity, long curing time, and high percolation threshold.

3D printing

silicone inks

viscosity

curing time

percolation threshold


Input: In the present study, a novel high-speed material jetting (MJ) 3D printing of high-viscosity conductive inks based on the mixture of a UV crosslinkable silicone rubber and milled carbon fibers (MCF) is demonstrated.

material jetting

MJ

3D printing

UV

silicone rubber

milled carbon fibers

MCF


Input: The MCF content was optimized for printability, UV curability, and electrical conductivity.

MCF

printability

UV curability

electrical conductivity


Input: The sensors (with 30 wt.

sensors


Input: % MCF content) show high flexibility and foldability as well as a high resistance sensitivity to sever bending tests.

MCF

as

as

flexibility

foldability

resistance sensitivity

bending tests


Input: The stretchability of 3D printed sensors was further improved by sandwiching the MCF/SR sensing layer between the SR layers.

stretchability

3D printed

sandwiching

MCF/SR

SR

layer


Input: The electromechanical evaluation of the sandwiched MCF/SR sensors (S-MCF/SR) confirmed the high piezoresistive sensitivity of sensors (gauge factor in order of ∼400).

electromechanical

sandwiched MCF/SR sensors

S-MCF/SR

sensors

piezoresistive sensitivity

gauge factor


Input: Finally, the 3D printed sensors were employed for monitoring human joint motions to demonstrate the potential application in monitoring biosignals.

3D printed

human joint motions

biosignals


Input: Polymer bonding of gas-atomized lightweight permanent magnet MnAlC particles.

Polymer

gas-atomized lightweight permanent magnet

bonding

particles


Input: Optimized particle size leads to flexible filament with high filling factor (80 wt%).

particle

filament

filling factor


Input: Extrusion of continuous permanent magnet MnAlC filaments (length over 10 m).

Extrusion

permanent magnet MnAlC filaments


Input: No deterioration of permanent magnet properties of MnAlC particles along processing.

permanent magnet properties

MnAlC particles


Input: 3D-printed permanent magnet objects avoiding the use of critical raw materials.

magnet

raw materials


Input: Additive manufacturing is an attractive technology for many high-tech sectors such as energy, automotive and aerospace because of the freedom in designing and high performance of the fabricated objects.

Additive manufacturing

technology

performance

fabricated

as

automotive

aerospace


Input: In the field of permanent magnets there is an increasing interest for applying this technology.

permanent magnets

technology


Input: However, key points need to be faced for obtaining products with non-deteriorated magnetic properties.

be

non-deteriorated magnetic properties


Input: Herein, we report on the preparation of MnAlC-based flexible filament with permanent magnet properties and a high filling factor of 80 wt% resulting from an optimum fine-to-coarse particle ratio (25/75), which has been successfully used for 3D-printing magnetic objects.

MnAlC-based flexible filament

permanent magnet properties

particle

filling factor


Input: Particles of MnAlC –rare earth-free permanent magnet– have been produced in nearly spherical shape with mean sizes of 16 and 30 μm by gas atomization.

Particles

spherical

MnAlC

gas atomization


Input: This has allowed for the fabrication of a permanent magnet composite, MnAlC/ABS, with a large concentration of MnAlC particles.

fabrication

permanent magnet composite

MnAlC/ABS

MnAlC particles


Input: The methodology here used has made possible the preparation of composite, filament and 3D-printed objects with no degradation of the permanent magnet properties.

methodology

degradation

permanent magnet properties

composite

filament


Input: The reported results open a new route to advance in the application of 3D-printing to fabricate permanent magnet elements with a high filling factor for technological applications.

fabricate

magnet

elements

filling factor


Input: We introduce an algorithm to generate tool paths using G2/G3-codes.

algorithm

tool paths


Input: The algorithms reduce time and cost while they enhance the quality of printed objects.

algorithms

quality


Input: Extrusion-based printing frequently requires a hollowing step to remove material from inside of artifacts and subsequently reduce the amount of material, printing time, product weight, energy consumption, and ultimately, the cost.

step

material

material

weight


Input: In addition to reducing stress concentration through their inherently smooth boundaries, these spheroids require no additional support structure, when properly designed.

stress concentration

smooth boundaries

support structure

designed


Input: Here, spheroids are arranged by the Voronoi diagram of 3D ellipsoids and the tool path, including circular printing motions, is produced using the Voronoi diagram of circular 2D disks.

tool path


Input: The proposed algorithms are implemented as the HollowTron webserver and are freely available from Voronoi Diagram Research Center.

algorithms

Research

as


Input: 3D printing allows rapid fabrication of complex objects from digital designs.

3D printing

rapid fabrication

designs


Input: One 3D-printing process, direct laser writing, polymerises a light-sensitive material by steering a focused laser beam through the shape of the object to be created.

direct laser writing

polymerises

focused laser beam

light-sensitive material

be

steering


Input: The highest-resolution direct laser writing systems use a femtosecond laser, steered using mechanised stages or galvanometer-controlled mirrors, to effect two-photon polymerisation.

highest-resolution

direct laser writing systems

femtosecond laser

galvanometer-controlled mirrors

two-photon polymerisation


Input: Here we report a new high-resolution direct laser writing system that employs a resonant mirror scanner to achieve a significant increase in printing speed over current methods while maintaining resolution on the order of a micron.

high-resolution

printing speed

resolution

direct laser writing system

mirror scanner

micron


Input: This printer is based on a software modification to a commercially available resonant-scanning two-photon microscope.

printer

two-photon microscope

software


Input: We demonstrate the complete process chain from hardware configuration and control software to the printing of objects of approximately 400 × 400 × 350 μm, and validate performance with objective benchmarks.

process chain

configuration

software

performance


Input: Released under an open-source license, this work makes micron-scale 3D printing available at little or no cost to the large community of two-photon microscope users, and paves the way toward widespread availability of precision-printed devices.

open-source

micron-scale

3D printing

two-photon microscope


Input: The introduction of three-dimensional (3D) printing in the pharmaceutical arena has caused a major shift towards the advancement of modern medicines, including drug products with different configurations and complex geometries.

three-dimensional

modern medicines

complex geometries

pharmaceutical