Input: Otherwise challenging to create via conventional pharmaceutical techniques, 3D printing technologies have been explored for the fabrication of multi-drug loaded dosage forms to reduce pill burden and improve patient adherence.

pharmaceutical techniques

multi-drug loaded dosage

pill burden

patient adherence

3D printing technologies

fabrication


Input: In this study, stereolithography (SLA), a vat polymerisation technique, was used to manufacture a multi-layer 3D printed oral dosage form (polyprintlet) incorporating four antihypertensive drugs including irbesartan, atenolol, hydrochlorothiazide and amlodipine.

stereolithography

vat polymerisation

3D printed

SLA

manufacture

polyprintlet

antihypertensive drugs

irbesartan

atenolol

hydrochlorothiazide

amlodipine


Input: Although successful in its fabrication, for the first time, we report an unexpected chemical reaction between a photopolymer and drug.

fabrication

chemical reaction

photopolymer


Input: Fourier Transform Infrared (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR) spectroscopy confirmed the occurrence of a Michael addition reaction between the diacrylate group of the photoreactive monomer and the primary amine group of amlodipine.

Fourier Transform Infrared

FTIR

NMR

spectroscopy

Nuclear Magnetic Resonance

spectroscopy

Michael addition reaction

diacrylate

photoreactive monomer

primary amine

amlodipine


Input: The study herein demonstrates the importance of careful selection of photocurable resins for the manufacture of drug-loaded oral dosage forms via SLA 3D printing technology.

photocurable resins

manufacture

drug-loaded oral dosage

SLA

3D printing technology


Input: Photopolymerization-based 3D printing has emerged as a promising technique to fabricate 3D structures.

Photopolymerization-based

fabricate 3D structures

3D printing

as


Input: However, during the printing process, polymerized materials such as hydrogels often become highly light-scattering, thus perturbing incident light distribution and thereby deteriorating the final print resolution.

printing process

polymerized materials

as

light-scattering

perturbing incident light distribution

print resolution


Input: To overcome this scattering-induced resolution deterioration, we developed a novel method termed flashing photopolymerization (FPP).

resolution deterioration

flashing photopolymerization

FPP


Input: Our FPP approach is informed by the fundamental kinetics of photopolymerization reactions, where light exposure is delivered in millisecond-scale ‘flashes’, as opposed to continuous light exposure.

FPP

photopolymerization

light exposure

millisecond-scale

continuous light exposure

as


Input: During the period of flash exposure, the prepolymer material negligibly scatters light.

flash exposure

prepolymer material


Input: The material then polymerizes and opacifies in absence of light, therefore the exposure pattern is not perturbed by scattering.

material

polymerizes

opacifies

exposure pattern


Input: Compared to the conventional use of a continuous wave (CW) light source, the FPP fabrication resolution is improved.

continuous wave

CW

light source

FPP

fabrication resolution


Input: FPP also shows little dependency on the exposure, thus minimizing trial-and-error type optimization.

FPP

exposure

trial-and-error

optimization


Input: Using FPP, we demonstrate its use in generating high-fidelity 3D printed constructs.

FPP

high-fidelity

3D printed constructs


Input: Material based actuation with metallic fibers, for example shape memory alloys (SMA) is gaining popularity to replace the conventional bulky actuators used for shape morphing in aerospace sectors.

Material

metallic fibers

shape memory alloys

actuators

aerospace


Input: However, Joule heating arising from electrical actuation of SMA affects the interfacial bonding between the SMA and the composite matrix and thus reduces the life span of the structure.

heating

electrical

interfacial bonding

structure

composite


Input: Insulating the SMA from the composite matrix will tremendously increase the service life of these reconfigurable structures.

Insulating

service life

composite


Input: Three-dimensional (3D) printing of functional elements during the fabrication phase of the composite structures permits the flexibility to form complex shaped reconfigurable lightweight aerospace components.

Three-dimensional

composite structures

lightweight

elements

fabrication

flexibility

aerospace components


Input: Here, we present a novel technique to embed polymer encapsulated functional elements into structural composites.

polymer

elements

composites

encapsulated


Input: We use the direct-write (DW) technique to coat SMA with a polymer solution while simultaneously printing them onto carbon fiber prepreg.

polymer

carbon fiber


Input: We develop high performance polymeric inks-polyetherimide and polycarbonate-compatible with the DW technique, the coating, as well as the composite.

performance

polycarbonate

as

as

composite

coating


Input: In addition to SMA, the technique can also be easily extended to embed various kinds of other functional fibers into composites, in any shape or form.

be

fibers

composites


Input: Additionally, we also demonstrate the application of this technique to integrate SMA with polymeric structures towards actuators for robotics grippers or surgical tools.

actuators

surgical tools

robotics


Input: The emergence of smart technologies is spurring the development of a wider range of applications for stretchable and conformable sensors, as the design flexibility offered by additive manufacturing may enable the production of sensors that are superior to those produced by conventional manufacturing techniques.

technologies

conformable

design flexibility

range

stretchable

as

additive manufacturing

production

conventional manufacturing

sensors


Input: In this work, a multi-material 3D printing system with three extrusion heads was developed to fabricate a stretchable, soft pressure sensor built using an ionic liquid (IL) –based pressure-sensitive layer that was sandwiched between carbon nanotube (CNT) –based stretchable electrodes and encapsulated within stretchable top and bottom insulating layers.

multi-material 3D printing

fabricate

extrusion heads

soft pressure sensor

electrodes

stretchable

stretchable

stretchable

ionic liquid

IL

carbon nanotube

CNT

pressure-sensitive layer

encapsulated

insulating layers


Input: The sensor materials were modified in order to achieve 3D printable characteristics.

sensor

materials

3D printable characteristics


Input: The capability of the system was tested by printing structures made from three materials and a multilayer sensor via an extrusion-based direct-print process.

materials

multilayer sensor

extrusion-based direct-print process


Input: Multi-material 3D printing of the sensor was successfully realized, as the sensing material retained its functionality once the printing process was complete.

Multi-material 3D printing

printing process

sensor

as

material

sensing


Input: Silicone-based materials are commonly used in medical applications such as pre-surgery models or implants, leading to interesting biomimetic mechanical properties.

Silicone-based materials

as

medical applications

implants

biomimetic

properties


Input: Emergence of 3D printing and particularly liquid deposition modelling (LDM) has shown that specific rheological behaviors, particularly yield stress characters, were required to achieve efficient LDM.

3D printing

liquid deposition modelling

LDM

LDM

rheological

yield stress


Input: Unfortunately, standard silicone formulations seldom present such behaviors and are then proved to have low applicability in LDM-based 3D printing.In the present study, polyethylene glycol of different lengths were added as yield stress agents in a bi-component silicone and were demonstrated to operate a drastic improvement of the material rheological behaviors, without significant impact on the final mechanical properties of the material.

standard

impact

mechanical properties

silicone

polyethylene glycol

as

bi-component silicone

material

material

LDM-based

stress


Input: An interesting relationship was demonstrated between dynamic yield stress values and reachable 3D geometries (the higher σys, the more complex the 3D printed shape can be) but the study also revealed that it is not the only key factor to ensure the printability of viscoelastic materials when highly complex geometries are seek; tack and melt strength have also to be investigated.

dynamic

materials

complex geometries

stress

viscoelastic

melt strength

3D geometries

3D printed

be

be

printability


Input: To improve the formability and properties of calcia (CaO) based ceramic core, the binder-jet 3D-printing was performed to fabricate porous CaO/caicium zirconate (CaZrO3) ceramic core composites with two nanozirconia addition methods.

formability

properties

calcia

CaO

CaO/caicium zirconate

nanozirconia

ceramic core

ceramic core

binder-jet 3D-printing

fabricate


Input: The effects of the nanozirconia addition method and additive amount on the properties of the 3D-printed CaO/CaZrO3 bodies were investigated.

nanozirconia

additive

properties


Input: The dimensional accuracy, surface roughness, relative density, bending strength, and hydration resistance of CaO/CaZrO3 bodies printed with a nanozirconia suspension binder for deposition in the CaO powder layer were better than those of CaO/CaZrO3 bodies printed in the traditional manner of directly mixing nanozirconia in the CaO powder.

dimensional accuracy

surface roughness

relative density

bending strength

resistance

nanozirconia

binder

CaO

CaO

deposition

mixing

layer


Input: Application of the nanozirconia suspension uniformly capped nanozirconia particles on the surfaces of the CaO particles and filled the pores of the CaO powder layer, which afforded denser and more uniform green bodies.

nanozirconia

nanozirconia

CaO

CaO

surfaces

green bodies

pores

layer


Input: After sintering at 1500 °C, the ZrO2 formed thicker and denser CaZrO3 layers with the CaO over the CaO grain surfaces, which improved the strength and hydration resistance of the sintered CaO/CaZrO3 ceramic core bodies, and certainly reduced their collapsibility.

sintering

sintered

CaO

CaO

surfaces

collapsibility

strength

resistance

core


Input: A 3D numerical model is developed to study the flow mechanism with rotation nozzle at the corner under various conditions during the extrusion and deposition process; Material rheological properties have little effects on material distribution ratio at corners, while process parameters affect material distribution ratio significantly; Increasing corner radius and relative nozzle travel speed while decreasing nozzle aspect ratio are beneficial to suppressing uneven mass distribution at corners; When conducting corner printing with rotational rectangular nozzle, a greater amount of material is deposited inside the filament and hence tearing and skewing will occur on the surface of the printed filament.

model

mechanism

properties

distribution

process parameters

distribution

distribution

surface

nozzle

nozzle

nozzle

nozzle

extrusion

deposition process

Material

material

material

material

filament

filament

aspect ratio


Input: With the aim of maintaining the surface finish and mechanical properties of the printed filament, a 3D numerical model is developed to study the flow mechanism at a corner under various conditions during the extrusion and deposition processes with rotational nozzle.

surface finish

mechanical properties

model

mechanism

filament

extrusion

deposition processes

nozzle


Input: After experimental validation, the numerical model is employed to study the material flow mechanism under various conditions.

experimental

model

mechanism

material


Input: The results indicate that the rheological properties have little effect on the mass distribution ratio.

rheological properties

distribution


Input: However, a high relative nozzle travel speed, larger corner radii and lower nozzle aspect ratio is a promising route in obtaining a uniform material distribution ratio.

nozzle

nozzle

aspect ratio

material

distribution


Input: The interlinking of process parameters affects the material distribution ratio significantly as well.

process parameters

distribution

material

as


Input: Furthermore, the importance of the factors that affect the mass distribution was determined quantitatively.

distribution

quantitatively


Input: Fused filament fabrication (FFF) is a 3D printing technique which allows layer-by-layer build-up of a part by the deposition of thermoplastic material through a nozzle.

Fused filament fabrication

FFF

3D printing

layer-by-layer

deposition

thermoplastic material

nozzle


Input: The technique allows for complex shapes to be made with a degree of design freedom unachievable with traditional manufacturing methods.

complex shapes

be

degree of design freedom

traditional manufacturing


Input: However, the mechanical properties of the thermoplastic materials used are low compared to common engineering materials.

mechanical properties

thermoplastic materials

engineering materials


Input: In this work, composite 3D printing feedstocks for FFF are investigated, wherein carbon fibres are embedded into a thermoplastic matrix to increase strength and stiffness.

composite

carbon fibres

thermoplastic matrix

3D printing

FFF

strength

stiffness


Input: First, the key processing parameters for FFF are reviewed, showing how fibres alter the printing dynamics by changing the viscosity and the thermal profile of the printed material.

parameters

printing dynamics

thermal profile

FFF

fibres

material

viscosity


Input: The state-of-the-art in composite 3D printing is presented, showing a distinction between short fibre feedstocks versus continuous fibre feedstocks.

state-of-the-art

composite

short fibre feedstocks

continuous fibre feedstocks

3D printing


Input: An experimental study was performed to benchmark these two methods.

experimental

benchmark


Input: It is found that printing of continuous carbon fibres using the MarkOne printer gives significant increases in performance over unreinforced thermoplastics, with mechanical properties in the same order of magnitude of typical unidirectional epoxy matrix composites.

continuous carbon fibres

unreinforced thermoplastics

unidirectional epoxy matrix composites

MarkOne printer

performance

mechanical properties

magnitude


Input: The method, however, is limited in design freedom as the brittle continuous carbon fibres can not be deposited freely through small steering radii and sharp angles.

design freedom

as

carbon fibres

be

brittle

steering radii

sharp angles


Input: Filaments with embedded short carbon microfibres (∼100 μm) show better print capabilities and are suitable for use with standard printing methods, but only offer a slight increase in mechanical properties over the pure thermoplastic properties.

Filaments

carbon microfibres

print capabilities

standard

mechanical properties

thermoplastic properties


Input: It is hypothesized that increasing the fibre length in short fibre filament is expected to lead to increased mechanical properties, potentially approaching those of continuous fibre composites, whilst keeping the high degree of design freedom of the FFF process.

fibre length

mechanical properties

degree of design freedom

fibre filament

lead

continuous fibre composites

FFF


Input: Water-soluble glass patterned by 3D printing is a versatile tool for tissue engineering and microfluidics.

Water-soluble glass

3D printing

versatile tool

tissue engineering

microfluidics


Input: Glasses can be patterned layer-by-layer as in conventional fused deposition modeling but also along 3D, “freeform” paths.

Glasses

be

as

layer-by-layer

freeform

fused deposition modeling


Input: In the latter approach, extruding heated material through a nozzle translating in 3D space allows for fabrication of sparse, freestanding networks of cylindrical filaments.

extruding

fabrication

material

nozzle

3D space

freestanding networks

cylindrical filaments


Input: These freeform structures are suitable for sacrificial molding with a variety of media, leaving complex microchannel networks.

freeform structures

microchannel networks

sacrificial molding


Input: However, 3D printing carbohydrate glass in this way presents several unique challenges: 1) the material must resist degradation and crystallization during printing, 2) the glass must be hot enough to flow freely during extrusion and fuse to the printed construct, while cooling rapidly to retain its shape upon exiting the nozzle, 3) the extruder needs to apply high pressure, with rapid stop and start times and 4) the net force that acts on the filament during extrusion must be minimized so that the filament shape is predictable, i.e., coincides with the path taken by the nozzle.

3D printing

extrusion

fuse

extrusion

glass

material

glass

be

filament

be

filament

degradation

crystallization

flow freely

printed construct

cooling rapidly

pressure

force

predictable

nozzle

extruder

nozzle


Input: First, we review the properties of commercially available carbohydrate glasses and provide a guide for processing isomalt, our material of choice, to achieve the best printing performance.

properties

printing performance

carbohydrate glasses

isomalt

material


Input: A pressure-controlled, piston-driven extruder is then described which allows for rapid responses and precise control over the material flow rate.

pressure-controlled

precise control

piston-driven extruder

material flow rate


Input: We then analyze the heat transfer within the filament and the forces that contribute to the filament’ s final shape.

heat transfer

forces

filament

filament

s


Input: We find that the dominant force is due to the radial flow of the molten glass as it exits the nozzle.

dominant force

radial flow

molten glass

as

nozzle


Input: This analysis is validated on a purpose-built isomalt 3D printer, which we utilize to characterize relationships between extrusion pressure, translation speed, filament diameter, and viscous force.

isomalt

3D printer

extrusion pressure

translation speed

filament diameter

viscous force


Input: The insights of the physics of the printing process enable fabrication of intricate freeform prints as well as layer-by-layer designs.

physics

intricate freeform prints

printing process

fabrication

as

as

designs


Input: The practical and theoretical considerations should facilitate adoption of additive manufacturing of carbohydrate glasses with applications to a wide variety of fields, including tissue engineering and microfluidics.

theoretical

tissue engineering

microfluidics

additive manufacturing

carbohydrate glasses


Input: Multi-material 3D printing with several mechanically distinct materials at once has expanded the potential applications for additive manufacturing technology.

Multi-material 3D printing

additive manufacturing

materials


Input: Fewer material options exist, however, for additive systems that employ vat photopolymerization (such as stereolithography, SLA, and digital light projection, DLP, 3D printers), which are more commonly used for advanced engineering prototypes and manufacturing.

material

as

additive systems

vat photopolymerization

digital light projection

DLP

manufacturing

SLA

3D printers

advanced engineering prototypes


Input: Those material selections that do exist are limited in their capacity for fusion due to disparate chemical and physical properties, limiting the potential mechanical range for multi-material printed composites.

material

multi-material printed composites

capacity

fusion

physical properties

mechanical


Input: Here, we present an ethylene glycol phenyl ether acrylate (EGPEA) -based formulation for a polymer resin yielding a range of elastic moduli between 0.6 MPa and 31 MPa simply by altering the ratio of monomer and crosslinker feedstocks in the formulation.

ethylene glycol phenyl ether acrylate

EGPEA

polymer resin

monomer

crosslinker feedstocks

range

elastic moduli

MPa

MPa


Input: This simple chemistry is also well suited to form seamless adhesions between mechanically dissimilar formulations, making it a promising candidate for multi-material DLP 3D printing.

simple

multi-material DLP 3D printing

chemistry

seamless adhesions

mechanically dissimilar formulations


Input: Preliminary tests with these polymer formulations indicate that variability due to molecular differences between hard and soft formulations is less than 3% of the prescribed model dimensions, comparable to existing commercial DLP and SLA resins, with unique advantages of a wide range of elastomer stiffness and seamless fusion for 3D printing of structurally detailed and mechanically heterogeneous composites.

polymer

resins

heterogeneous composites

variability

molecular differences

model dimensions

seamless fusion

DLP

3D printing

SLA

range

elastomer stiffness


Input: We introduce a novel divide-and-conquer approach for 3D printing, which provides automatic decomposition and configuration of an input object into print-ready components.

3D printing

decomposition

configuration

components


Input: Our method improves 3D printing by reducing material consumption, decreasing printing time, and improving fidelity of printed models.

3D printing

material


Input: Then the configuration phase provides a robust algorithm to pack the components for an efficient print job.

configuration

algorithm

components

print


Input: Our results show that the framework can reduce print time by up to 65% (fused deposition modeling, or FDM) and 36% (stereolithography, or SLA) on average and diminish material consumption by up to 35% (FDM) and 10% (SLA) on consumer printers, while also providing more accurate objects.

framework

average

print

fused deposition modeling

FDM

stereolithography

FDM

SLA

SLA

printers

material

accurate


Input: Conventional 3D printing approaches are restricted to building up material in a layer-by-layer format, which is more appropriately considered “2.5-D” printing.

3D printing

building up material

layer-by-layer


Input: The layered structure inherently results in significant mechanical anisotropy in printed parts, causing the tensile strength in the build direction (z-axis) to be only a fraction of the in-plane strength–a decrease of 50–75% is common.

layered structure

z-axis

fraction

mechanical anisotropy

tensile strength

in-plane strength

build direction

be


Input: In this study, a novel “z-pinning” approach is described that allows continuous material to be deposited across multiple layers within the volume of the part.

z-pinning

material

be

volume


Input: The z-pinning process is demonstrated using a Fused Filament Fabrication (FFF) printer for polylactic acid (PLA) and carbon fiber reinforced PLA.

z-pinning

process

Fused Filament Fabrication

FFF

printer

polylactic acid

PLA

carbon fiber reinforced PLA


Input: For both materials, z-pinning increased the tensile strength and toughness in the z-direction by more than a factor of 3.5.

materials

z-pinning

tensile strength

toughness

z-direction


Input: Direct comparisons to tensile strength in the x-axis showed a significant decrease in mechanical anisotropy as the volume of the pin was increased relative to the void in the rectilinear grid structure.

tensile strength

mechanical anisotropy

as

volume

void

rectilinear grid structure


Input: In fact, the PLA sample with the largest pin volume demonstrated mechanically isotropic properties within the statistical uncertainty of the tests.

PLA

volume

isotropic


Input: Tensile test results were also analyzed relative to the functional area resisting deformation for each sample.

Tensile test

area

deformation

sample


Input: Digital light processing 3D printing method was used to fabricate conductive parts.

Digital light processing 3D printing

fabricate


Input: MWCNTs were used with photocurable resin to form conductive ink for 3D printing.

photocurable resin

ink

3D printing


Input: Complicated 3D conductive structures were demonstrated.


Input: These structures can be used as capacitive sensors and shape memory composites.

be

as

composites

sensors


Input: 3D printing has gained significant research interest recently for directly manufacturing 3D components and structures for use in a variety of applications.

3D printing

manufacturing

research


Input: In this paper, a digital light processing (DLP®) based 3D printing technique was explored to manufacture electrically conductive objects of polymer nanocomposites.

digital light processing

3D printing

manufacture electrically

polymer


Input: Here, the ink was made of a mixture of photocurable resin with multi-walled carbon nanotubes (MWCNTs).

ink

photocurable resin

carbon nanotubes


Input: The concentrations of MWCNT as well as the printing parameters were investigated to yield optimal conductivity and printing quality.

as

as

parameters

quality

conductivity


Input: We found that 0.3 wt% loading of MWCNT in the resin matrix can provide the maximum electrical conductivity of 0.027S/m under the resin viscosity limit that allows high printing quality.

resin

resin

electrical conductivity

limit

quality


Input: With electric conductivity, the printed MWCNT nanocomposites can be used as smart materials and structures with strain sensitivity and shape memory effect.

conductivity

strain

shape memory effect

be

as

materials

sensitivity


Input: We demonstrate that the printed conductive complex structures as hollow capacitive sensor, electrically activated shape memory composites, stretchable circuits, showing the versatility of DLP® 3D printing for conductive complex structures.

printed conductive

sensor

complex structures

electrically

as

composites

stretchable

conductive complex structures

3D printing


Input: In addition, mechanical tests showed that the addition of MWCNT could slightly increase the modulus and ultimate tensile stress while decreasing slightly the ultimate stretch, indicating that the new functionality is not obtained at the price of sacrificing mechanical properties.

mechanical tests

tensile stress

mechanical properties


Input: 3D printing technology has revolutionized the field of machinery, aerospace, and electronics.

3D printing technology

aerospace

electronics


Input: To address the shortcomings of previous studies on improving the poor mechanical properties of the resin used in 3D printers, this study presents a technology for fabricating short fibres or a continuous fibre-composite material using stereolithography 3D printing.

mechanical properties

technology

resin

fibres

material

3D printers

fabricating

stereolithography 3D printing


Input: Glass powder and fibreglass fabric were used as the discontinuous and continuous fibre reinforcement of light-cured resin material.

Glass

as

fibre

resin material


Input: The tensile strength and Young’ s modulus showed a marked increase: these were 7.2 and 11.5 times higher than those of the resin specimen, respectively.

tensile strength

s

resin


Input: The 3D printing of fiber-reinforced soft composites (FrSCs) is a hybrid process that combines conventional inkjet-based 3D printing with the directed deposition of electrospun polymer fiber mats.

3D printing

3D printing

composites

polymer fiber

mats

process

deposition


Input: This paper investigates the spreading characteristics of droplets when deposited on fibrous substrates, under conditions relevant to 3D printing of aligned FrSCs.

investigates

droplets

fibrous

3D printing


Input: High-speed imaging is used to study the characteristic time-scales and the spreading behavior of the droplets.

imaging

droplets


Input: The single droplet impingement studies on stationary substrates reveal that the presence of fibers promotes droplet spreading along the length of the fibers.

droplet

droplet

fibers

fibers


Input: Occasional surface energy variations in the fiber mats in the form of voids and fiber bundles are also seen to affect the droplet shape and the characteristic spreading times.

surface

variations

voids

droplet

fiber

fiber bundles


Input: In the case of a moving substrate, the droplets are seen to spread the most during in-line printing, i.e., when the direction of the printing velocity coincides with the direction of fiber alignment.

substrate

droplets

spread

fiber alignment


Input: They spread the least during orthogonal printing, i.e., when the direction of the printing velocity is perpendicular to the direction of fiber alignment.

spread

fiber alignment


Input: The findings of the high-speed imaging studies have been confirmed by 3D printing comparable artifacts using UV curable inks.

imaging

3D printing

UV


Input: These studies indicate that for a given fiber mat and UV curable ink combination, the choice of the in-line or orthogonal printing strategy has implications for the overall printing time, fiber content, edge resolution and surface quality of the 3D printed FrSC part.

fiber

ink

fiber

UV

resolution

surface quality

3D printed


Input: Multi-material extrusion in 3D printing is gaining attention due to a wide range of possibilities that it provides, specially driven by the commercial availability of a large variety of non-conventional filament materials.

Multi-material

extrusion

3D printing

range

filament


Input: With this in mind, this paper addresses the mechanical performance of multi-material printed objects, specially focused on the interface zone generated between the different materials at their geometrical boundaries.

mechanical

multi-material

interface

materials

boundaries


Input: Tensile test specimens were designed and printed in three types: (A) a single-material specimen printed by a single extrusion head; (B) a single-material but multi-section specimen printed in a zebra-crossing structure by two extrusion heads; and (C) a multi-material specimen printed with two materials in a zebra-crossing pattern.

Tensile test

designed

extrusion head

extrusion heads

B

C

structure

multi-material

materials

pattern


Input: The materials considered were PLA, TPU and PET.

materials

PLA


Input: The comparison of the mechanical performance between Type-A and -B specimens demonstrated the negative influence of the presence of a geometrical boundary interface between the same material.

mechanical

boundary

material


Input: The methodology proposed to assess the quality of the pairs of materials selected is innovative, and enabled to depict the importance of the boundary design in multi-material printing techniques.

methodology

quality

materials

boundary

multi-material printing


Input: The aim of the present work was to develop a pilot scale process to produce drug-loaded filaments for 3D printing of oral solid dose forms by fused filament fabrication (FFF).

process

filaments

3D printing

fused filament fabrication

FFF


Input: Using hot melt extrusion, a viable operating space and understanding of processing limits were established using a hydrophilic polymer (hydroxypropyl methylcellulose (HPMC)–Affinisol™ LV15).

melt extrusion

limits

polymer


Input: From the process development work, challenges in achieving a pilot scale process for filament production for pharmaceutical applications have been highlighted.

process

process

filament

pharmaceutical


Input: 3D printing trials across the range of compositions demonstrated limitations concerning the ability to print successfully across all compositions.

3D printing

print

range


Input: Results from characterisation techniques including thermal and mechanical testing when applied to the formulated filaments indicated that these techniques are a useful predictive measure for assessing the ability to print a given formulation via filament methods.

mechanical testing

filaments

filament

print


Input: However, fabrication methods using three-dimensional (3D) bioprinters are limited by the simple nozzle-based extrusion or uncontrollability of photo-reactive systems.

fabrication

simple

extrusion

three-dimensional


Input: Hence, most studies on inducing topographical cues were focused on two-dimensional (2D) surface structures and based on imprinting and soft-lithography processes.

two-dimensional

processes

surface structures


Input: Although 2D patterned surfaces provide outstanding insight into optimal patterned architectures by facilitating the analysis of various myoblast responses, it can be difficult to achieve complex 3D structures with microscale topographical cues.

surfaces

3D structures

microscale

be


Input: For this reason, we propose a new strategy for obtaining topographical cues in 3D printed synthetic biopolymers for regenerating muscle tissue.

3D printed

biopolymers


Input: A uniaxially aligned pattern was obtained on the struts of the matrix composed of poly (ε-caprolactone) (PCL) or poly (lactic-co-glycolic acid) (PLGA), by taking advantage of the immiscible rheological properties and flow-induced force in the dispersed pluronic F-127 phase (sacrificial material) and matrix materials.

pattern

force

phase

materials

struts

PCL

PLGA

material

rheological properties


Input: Stereolithography is a 3D printing technique in which a liquid monomer is photopolymerized to produce a solid object.

Stereolithography

3D printing

monomer


Input: Photoinitiators can absorb UV or (less often) visible light, producing radicals for direct decomposition or hydrogen abstraction.

UV

abstraction

decomposition


Input: In fact, vegetable oils contain unsaturations, and thus, they can be exploited as monomers.

oils

be

as


Input: In particular, linseed oil, tung oil or edible oils (soybean, sunflower or corn) could be good candidates as raw materials.

oil

oil

oils

be

as

materials


Input: Unfortunately, the photoinduced radical polymerization of these oils either does not occur or is too slow for 3D printing applications.

polymerization

3D printing

oils


Input: For this reason, the oils were modified as epoxides.

oils

as


Input: Epoxides are monomers that are more reactive than natural oils, and they can be polymerized via a cationic mechanism.

oils

be

mechanism


Input: The aim of this work was to exploit visible light generated by a common digital projector (like those used in classrooms) as a light source.

projector

light source

as


Input: Vegetable oil epoxides, together with curcumin and visible light could replace acrylates from 3D printing.Download: Download high-res image (82 Challenging to 3-D print functional parts with known mechanical properties.

oil

high-res image

mechanical properties


Input: Using variable open source 3-D printers for a wide range of materials.

source

materials

range


Input: Tested tensile strength following ASTM D638 for fused filament fabrication.

tensile strength

fused filament fabrication


Input: Tensile strength of a 3-D printed specimen depends largely on the mass.

Tensile strength


Input: 2 step process developed to screen 3-D prints for mechanical functionality.

step process

mechanical functionality


Input: 3D printing functional parts with known mechanical properties is challenging using variable open source 3D printers.

3D printing

mechanical properties

source

3D printers


Input: This study investigates the mechanical properties of 3D printed parts using a commercial open-source 3D printer for a wide range of materials.

investigates

mechanical properties

open-source

materials

3D printed parts

3D printer

range


Input: The samples are tested for tensile strength following ASTM D638.

samples

tensile strength


Input: The results are presented and conclusions are drawn about the mechanical properties of various fused filament fabrication materials.

mechanical properties

fused filament fabrication


Input: The study demonstrates that the tensile strength of a 3D printed specimen depends largely on the mass of the specimen, for all materials.

tensile strength

3D printed

materials


Input: Thus, to solve the challenge of unknown print quality on mechanical properties of a 3D printed part a two step process is proposed, which has a reasonably high expectation that a part will have tensile strengths described in this study for a given material.

print quality

mechanical properties

step process

3D printed part

tensile strengths

material


Input: This mass is compared to the theoretical value using densities for the material and the volume of the object.

theoretical

volume

material


Input: This two step process provides a means to assist low-cost open-source 3D printers expand the range of object production to functional parts.

step process

open-source

3D printers

range

production


Input: Novel blend feedstocks developed using recycled plastic materials.

blend

plastic

recycled

materials


Input: Blend composition and processing conditions optimized for morphology/interfacial adhesion.

Blend

adhesion


Input: Blend perform on par with commercial HIPS filaments.

Blend

HIPS filaments


Input: Recycled polymer blends are valid feedstocks for AM and could be used for manufacturing in remote environments.

Recycled

polymer blends

feedstocks

be

AM

manufacturing


Input: Consumer-grade plastics can be considered a low-cost and sustainable feedstock for fused filament fabrication (FFF) additive manufacturing processes.

plastics

be

feedstock

sustainable

fused filament fabrication

FFF

additive manufacturing processes


Input: Such materials are excellent candidates for distributed manufacturing, in which parts are printed from local materials at the point of need.

materials

materials

manufacturing


Input: Most plastic waste streams contain a mixture of polymers, such as water bottles and caps comprised of polyethylene terephthalate (PET) and polypropylene (PP), and complete separation is rarely implemented.

plastic

polymers

as

polyethylene terephthalate

polypropylene


Input: In this work, blends of waste PET, PP and polystyrene (PS) were processed into filaments for 3D printing.

blends

polystyrene

filaments

processed

3D printing


Input: The effect of blend composition and styrene ethylene butylene styrene (SEBS) compatibilizer on the resulting mechanical and thermal properties were probed.

blend

mechanical

thermal properties


Input: Recycled PET had the highest tensile strength at 35 ± 8 MPa.

Recycled

MPa

tensile strength


Input: Blends of PP/PET compatibilized with SEBS and maleic anhydride functionalized SEBS had tensile strengths of 23 ± 1 MPa and 24 ± 1 MPa, respectively.

Blends

tensile strengths

MPa

MPa


Input: The non-compatibilized PP/PS blend had a tensile strength of 22 ± 1 MPa.

blend

tensile strength

MPa


Input: PP/PS blends exhibited reduced tensile strength to ca.

blends

ca

tensile strength


Input: Elongation to failure was generally improved for the blended materials compared to neat recycled PET and PS.

Elongation

failure

materials

recycled


Input: The glass transition was shifted to higher temperatures for all of the blends except the 50–50 wt.

glass

blends

temperatures


Input: % PP/PET blend.

blend


Input: % PP/PET blend with SEBS-maleic anhydride.

blend


Input: Solvent extraction of the dispersed phase revealed polypropylene was the matrix phase in both the 50–50 wt.

phase

phase

polypropylene


Input: % PP/PET and PP/PS blends.

blends


Input: Porous tricalcium phosphate (TCP) scaffolds are becoming more and more important for treating musculoskeletal diseases.

Porous

phosphate

scaffolds


Input: With the maturation of 3D printing (3DP) technology in the past two decades, porous TCP scaffolds can also be easily prepared with complex design and high dimensional accuracy.

3D printing

technology

porous

scaffolds

design

be

dimensional accuracy


Input: However, the mechanical and biological properties of porous TCP scaffolds prepared by 3D printing still need improvements.

mechanical

properties

porous

scaffolds

3D printing


Input: In this study, novel 3D printed TCP and MgO/ZnO-TCP scaffolds were prepared by an binder-jet 3D printer.

3D printed

scaffolds

3D printer


Input: Scaffolds had a dense core and porous surface feature with a designed pore size of 500 μm and a designed porosity of 18%.

Scaffolds

feature

designed

designed

core

porous


Input: After printing, scaffolds were sintered in a muffle furnace at 1250 °C.

scaffolds

sintered

furnace


Input: The presence of MgO and ZnO increased the surface area of TCP from 1.18 ± 0.01 m2/g to 2.65 ± 0.02 m2/g, the bulk density from 37.89 ± 0.83% to 50.82 ± 1.10%, and the compressive strength from 17.94 ± 1.65 MPa to 27.46 ± 2.63 MPa.

MgO

surface area

density

compressive strength

MPa

MPa


Input: Enhanced osteoblast proliferation was shown in doped 3D printed TCP scaffolds compared to the pure 3DP TCP.

osteoblast

3D printed

scaffolds


Input: In addition, the use of 3D printing as well as dense core and porous surface design enhanced the surface roughness and osteoblast proliferation of TCP scaffolds.

3D printing

as

core

porous

surface roughness

design

osteoblast

TCP scaffolds


Input: This novel 3D printed MgO/ZnO-TCP scaffold shows enhanced mechanical and biological properties, which is promising for orthopedic and dental applications.

3D printed

scaffold

mechanical

dental applications

properties


Input: Additive manufacturing (AM), which is also referred to as 3D printing, is a class of manufacturing techniques that fabricate three dimensional (3D) objects by accumulating materials.

Additive manufacturing

AM

3D printing

manufacturing

fabricate

as

materials


Input: Constrained surface based stereolithography is one of the most widely used AM techniques.

surface

stereolithography

AM techniques


Input: In the process, a thin layer of liquid photosensitive resin is constrained between a constrained surface and the platform or part.

process

surface

layer

photosensitive resin

platform


Input: The light penetrates the transparent constrained surface and cures that layer of liquid polymer.

transparent

surface

layer

polymer


Input: Then the platform is moved up to separate the newly cured layer to let new liquid resin fill into the gap and get cured.

platform

cured layer

resin

cured


Input: The separation of newly cured layer from the constrained surface is a grand challenge that limits the printable size and printing speed in this manufacturing technique.

cured layer

surface

limits

printing speed

manufacturing


Input: Numerous experimental works have been performed to understand how to reduce the separation force in the process.

experimental

separation force

process


Input: In this paper we study a new design of constrained surface with radial groove texture that significantly influences the effectiveness of reduction of the separation force and hence the manufacturing capability via theoretical modeling.

design

texture

surface

effectiveness

reduction

separation force

theoretical

manufacturing

modeling


Input: The proposed model is validated with numerical simulations demonstrating an excellent agreement.

model

numerical simulations


Input: We demonstrate the possibility of drastic reduction of the separation force (up to 112%) via surface texturing of the permeable window for continuous 3D printing.

reduction

separation force

surface texturing

3D printing


Input: A novel large-scale 3D printer is introduced.

3D printer


Input: A full scaffolding solution allows any 3D geometry to be printed.

scaffolding

3D geometry

be


Input: Part geometry errors are detected and corrected using geometric feedback.

geometry errors

feedback


Input: Although additive manufacturing (AM) is now a well-established industry, very few large-scale AM systems have been developed.

additive manufacturing

AM

AM

industry


Input: Here, a large-scale 3D printer is introduced, which uses a six-degree-of-freedom cable-suspended robot for positioning, with polyurethane foam as the object material and shaving foam as the support material.

3D printer

robot

polyurethane foam

as

material

foam

as

support material

shaving


Input: Cable-positioning systems provide large ranges of motion and cables can be compactly wound on spools, making them less expensive, much lighter, more transportable, and more easily reconfigurable, compared to the gantry-type positioning systems traditionally used in 3D printing.

be

positioning systems

3D printing


Input: The 3D foam printer performance is demonstrated through the construction of a 2.16-m-high statue of Sir Wilfrid Laurier, the seventh Prime Minister of Canada, at an accuracy of approximately 1 cm, which requires 38 h of printing time.

performance

printer

construction

accuracy


Input: The system advantages and drawbacks are then discussed, and novel features such as unique support techniques and geometric feedback are highlighted.

as

support

feedback


Input: PA/ABS blend optimized formulation improved bead-bead adhesion in 3-D printing.

blend

adhesion


Input: Anisotropy ratio (z property/x property) indicator of bead-bead adhesion.

Anisotropy

adhesion

property


Input: Small-scale printing can provide test case for large-scale printed material properties.

material properties


Input: SMA was an effective compatiblizer for PA/ABS blends at printed interface.

blends

interface


Input: For additive manufacturing interfacial adhesion (bead-bead) remains an important issue affecting uniformity of mechanical properties.

additive manufacturing

adhesion

mechanical properties


Input: The present work examined the role a compatibilizer would play when used in fused filament fabrication (FFF) printing.

fused filament fabrication

FFF


Input: Both small and large-scale 3-D component properties were examined.

properties


Input: The mechanical property anisotropy ratio, an indication of bead-bead adhesive strength (defined as a property measured along the z axis versus the x axis) is representative of adhesive strength.

mechanical property

property

anisotropy

adhesive

as

adhesive


Input: Large-scale (big area additive manufacturing, BAAM) tests (flexural properties) showed 62% improvement in the anisotropy ratio for modulus, 77% improvement in the anisotropy ratio of the strength, 56% improvement in the anisotropy ratio of elongation at break, and 55% improvement of the anisotropy ratio of the Charpy impact strength over the control PA values.

area

additive manufacturing

properties

impact

anisotropy

anisotropy

strength

anisotropy

elongation

anisotropy

PA


Input: Thus, use of compatibilized polymer blends can provide customized materials without the need for new chemistry.

polymer blends

materials

chemistry


Input: Addition of maleic anhydride-compatibilized ABS improved PA blend bead-bead adhesion.

ABS

blend

PA

adhesion


Input: The thixotropic ink is able to maintain the shape after direct printing.

thixotropic

ink


Input: MNPs interact with polymer network and alter its physicochemical properties.

polymer

properties


Input: Nanofiller renders the 3D-printed hydrogel magnetic.


Input: 3D-printed objects can be remotely actuated via magnetic fields.

be

magnetic fields


Input: Magnetic hydrogels have a myriad of promising applications including soft electronics, flexible robotics, biomedical devices, and wastewater treatment.

hydrogels

electronics

robotics

biomedical

wastewater treatment


Input: However, their potential is limited by conventional fabrication methods which impede creating convoluted geometries.

fabrication

geometries


Input: 3D printing may replace traditional fabrication techniques as it has an ability to fabricate complex shapes using a wide variety of materials.

3D printing

fabrication

fabricate

as

complex shapes

materials


Input: A new 3D printing ink, a bionanocomposite based on alginate, methylcellulose and magnetic nanoparticles (MNPs) was used to print pre-designed high-quality 3D structures.

3D printing

print

alginate

nanoparticles

3D structures


Input: Three-dimensional hydrogel constructs had good mechanical stability and exhibited responsiveness to an applied magnetic field.

Three-dimensional

magnetic field

hydrogel

mechanical


Input: Inclusion of the MNPs within the hydrogel and its precursor (ink) influenced their rheological properties-and mechanical stability.

Inclusion

hydrogel

precursor

ink

rheological properties

mechanical


Input: MNPs were found to play dual roles: (1) as a nanofiller that interacts with polymer backbone and alters its physicochemical properties, and (2) as a function provider that renders a bionanocomposite magnetic.

as

polymer

as

properties


Input: The magnetic ink allows for the fabrication of multi-material structures such as hydrogels with a magnetic nanoparticle gradient.

ink

as

fabrication

multi-material structures


Input: 3D-printed objects can be remotely actuated via magnetic fields.

be

magnetic fields


Input: Reactive magnesium oxide cement (RMC) is gaining increasing attention as a sustainable construction material due to its significantly low carbon footprint during the production as well as the operational phase compared to the conventional Portland cement.

magnesium oxide

cement

as

as

as

cement

RMC

sustainable

carbon footprint

phase

construction

production


Input: Whereas several studies have demonstrated the potential of RMC as a suitable and environment-friendly construction material, this study reports that RMC can be shaped into complex structures via three-dimensional (3D) printing technology.

RMC

RMC

as

be

construction

complex structures

three-dimensional

printing technology


Input: By adding suitable additives and only 3 wt.

additives


Input: % of caustic magnesium oxide to the commercially available RMC, appropriate rheology and buildability were achieved that enabled smooth 3D printing of complex structures with precise shape retention.

magnesium oxide

RMC

rheology

3D printing

complex structures


Input: Moreover, the 3D printed RMC exhibited higher densification and nearly twofold the compressive strength as compared to its cast counterpart.

3D printed

densification

cast

compressive strength

as


Input: Therefore, this work demonstrates the potential of RMC as a 3D printable construction material for sustainable and modern architecture.

RMC

as

sustainable

construction

architecture


Input: Achievement of optimized lateral and vertical resolution is a key factor to obtaining three-dimensional (3D) structural details fabricated through digital light processing (DLP) -based 3D printing technologies which exploit digitalized ultraviolet (UV) or near-UV light to trigger localized photopolymerization forming solid patterns from liquid polymer resins.

vertical

three-dimensional

fabricated

ultraviolet

UV

resolution

digital light processing

DLP

photopolymerization forming

3D printing technologies

polymer resins


Input: Many efforts have been made to optimize printing resolution through improving the optical systems.

resolution

optical


Input: However, researchers have paid comparatively little attention to understand the influences of polymer formulation on the printing resolution and surface quality.

polymer

resolution

surface quality


Input: Here, we report an investigation on the effects of in-house formulated (meth) acrylate-based photopolymer constituent types and concentrations on the resolution and quality of structures printed on a bottom-exposure DLP-based 3D printing system.

photopolymer

resolution

quality

3D printing


Input: We examined a wide variety of resin formulations to determine optimal formulations that yield best printing resolution and surface quality over a reasonably broad range of mechanical properties.

resin

resolution

surface quality

range

mechanical properties


Input: We demonstrated the controlled fabrication of sub-pixel conical and aspherical smooth features, whereby the shape and dimensions could be prescribed with the resin formulation and process parameters.

fabrication

dimensions

be

resin

process parameters


Input: Such features hold promising implications in micro-optic and microfluidic fabrication using the DLP-based 3D printing technique.

fabrication

3D printing


Input: Use of this solution minimized the ‘stair-stepping’ effect in components printed in a layer-by-layer manner.

solution

layer-by-layer

components


Input: Taken together, the present findings provide a basis for optimized photopolymer resin formulations that retain maximum vertical and lateral resolutions and minimal surface roughness and layering artifacts for a versatile range of mechanical and rheological properties suited to novel applications in 3D printing of smooth free-form solids, micro-optics, and direct fabrication of microfluidic platforms with functional surfaces.

photopolymer resin

vertical

surfaces

surface roughness

rheological properties

range

mechanical

3D printing

fabrication


Input: The optimization of slurry compositions and processing parameters has significant potential for layered extrusion forming, a novel slurry-based additive manufacturing method.

optimization

parameters

slurry

extrusion

additive manufacturing


Input: The optimal slurry composition was composed of 50vol.% Al2O3 loading, 1.5wt.% acetic acid as dispersant and 2wt.% methylcellulose solution as binder.

slurry

as

as

composition

solution


Input: The processing parameters including layer height, print speed and nozzle diameter significantly influenced the fabrication quality.

parameters

nozzle diameter

layer height

print

fabrication


Input: The orthogonal experiment showed that the print speed of 15mm/s, nozzle diameter of 0.40mm and layer height set as 70% of nozzle diameter was the optimized processing conditions.

experiment

nozzle diameter

nozzle diameter

print

layer height

as


Input: The lattice structure constructed under the optimized conditions exhibited uniform and well-shaped morphology before and after sintering.

lattice structure

morphology

sintering


Input: The solid-infilled ceramic specimen prepared via optimized parameters exhibited uniform structure and the surface roughness was 0.75μm, which greatly improved the surface quality.

ceramic

parameters

structure

surface roughness

surface quality


Input: Current 3D printing capabilities onboard the International Space Station (ISS) are classified as experimental payloads.

3D printing

as


Input: As payloads the products of these printers are returned to the ground for testing and analysis.

As

printers

testing


Input: However, it has long been thought that 3D printing must one day become a tool of space operations much like the electrical diagnostic equipment, and the soldering iron.

3D printing

soldering

tool

equipment

electrical

iron


Input: This paper explores a case study in the use of one of the payload 3D printers to manufacture a device to be used by the crew as part of nominal ISS Operations.

case study

manufacture

3D printers

be

as


Input: The path from concept development through onboard printing and crew inspection will be described.

inspection

be


Input: The lessons learned from this process are reviewed as constructive feedback on how existing processes can be expanded to enable this capability in the future.

process

processes

as

be

feedback


Input: This experience will be carried forward into the development of a new process which will open the door for future use of 3D printing onboard the ISS.

be

process

3D printing


Input: Continuous fiber–reinforced thermosetting polymer composites (CFRTPCs) were prepared via three–dimensional (3D) printing.

thermosetting polymer

composites


Input: Typical process parameters were systematically investigated over a wide range.

process parameters

range


Input: 3D printed CFRTPC samples exhibited maximum flexural strength and modulus of 952.89 MPa and 74.05 GPa, respectively.

3D printed

samples

MPa

flexural strength

GPa


Input: Mechanical performance of the optimized process has increased nearly an order of magnitude than the previous reports.

Mechanical

process

magnitude


Input: Advanced composite structures can be 3D printed for potential applications in the future research.

Advanced composite

be

3D printed

research


Input: Continuous fiber-reinforced thermosetting polymer composites (CFRTPCs) were prepared via three-dimensional (3D) printing in this study.

thermosetting polymer

composites

three-dimensional


Input: The entire process was divided into impregnation, printing, and curing stages.

process

impregnation

curing


Input: The impregnation stage ensured a tightly bonded interface and uniform distribution of fibers and resin.

impregnation

interface

distribution

fibers

resin


Input: The printing stage solved the great conveying resistance and poor adhesion caused by the addition of continuous fibers.

resistance

adhesion

continuous fibers


Input: The curing stage aimed to preserve the shapes of the pre-formed samples and completed the polymerization and crosslinking reactions.

curing

polymerization

samples


Input: An investigation into the experimental design focused on optimizing the parameters of the manufacturing process, wherein printing speed, printing space, printing thickness, curing pressure, and curing temperature were selected as target variables.

experimental design

parameters

manufacturing process

curing

curing

printing speed

as


Input: Finally, 3D printed CFRTPC samples with 58 wt.% fiber content exhibited maximum flexural strength and modulus of 952.89 MPa and 74.05 GPa, respectively.

3D printed

samples

MPa

fiber

flexural strength

GPa


Input: Moreover, complex CFRTPC components were fabricated to demonstrate the feasibility and generality of the proposed technique.

components

fabricated

feasibility


Input: These results may broaden the potential use of 3D printed CFRTPCs in aerospace, defense, and automotive applications.

3D printed

aerospace

automotive


Input: A hybrid multi-objective optimization approach is proposed to optimize the printed line quality.

optimization

quality


Input: The inherent contradiction is analyzed by a statistical response surface methodology.

response surface methodology


Input: The robust 3D optimal Pareto front is identified based on statistical uncertainty and a genetic algorithm.

Pareto

genetic algorithm


Input: Aerosol jet printing (AJP) is an emerging 3-dimensional (3D) printing technology to fabricate customized and conformal microelectronic components on various flexible substrates.

printing technology

fabricate

components


Input: Although the AJP technology has the capability of depositing fine features, the inherent contradiction between the printed line thickness and line edge roughness has a great impact on the printed line quality.

technology

impact

quality

roughness


Input: The proposed approach consists of a central composite design (CCD), a response surface methodology, a desirability function approach and a non-dominated sorting genetic algorithm III (NSGA-III).

composite

response surface methodology

genetic algorithm


Input: In the proposed approach, the response surface methodology is combined with the CCD to investigate and quantify the correlations between the printed line features and the key process parameters.

response surface methodology

process parameters


Input: And the conflicting relationship between the printed line edge roughness and line thickness is identified by the CCD derived response surface models (RSMs).

roughness

surface models


Input: The experimental results demonstrate that the proposed hybrid multi-objective optimization approach is beneficial to minimize the conflict between the printed line features, hence the lines can be produced with low line edge roughness and sufficient line thickness.

experimental

optimization

be

roughness


Input: Different from a traditional trial-and-error method in AJP, the proposed printing quality optimization approach is developed based on the principles of statistical modeling, analysis of variance and global optimization.

trial-and-error

quality optimization

optimization

modeling


Input: Therefore, the proposed printing quality optimization approach is more efficient and systematic.

quality optimization


Input: Moreover, the data-driven based characteristic makes the proposed approach applicable to other multi-objective optimization researches in additive manufacturing technologies.

optimization

additive manufacturing


Input: We explore elastic wave focusing and enhanced energy harvesting by means of a 3D-printed Gradient-Index Phononic Crystal Lens (GRIN-PCL) bonded on a metallic host structure.

elastic

energy harvesting

structure

Lens

metallic


Input: The lens layer is fabricated by 3D printing a rectangular array of cylindrical nylon stubs with varying heights.

lens

3D printing

layer

fabricated

cylindrical


Input: The stub heights are designed to obtain a hyperbolic secant distribution of the refractive index to achieve the required phase velocity variation in space, hence the gradient-index lens behavior.

designed

distribution

phase

variation

lens


Input: Finite element simulations are performed on composite unit cells with various stub heights to obtain the lowest antisymmetric mode Lamb wave band diagrams, yielding a correlation between the stub height and refractive index.

Finite element

composite

cells


Input: The elastic wave focusing performance of lenses with different design parameters (gradient coefficient and aperture size) is simulated numerically under plane wave excitation.

elastic

performance

design

excitation


Input: It is observed that the focal points of the wider aperture lens designs have better consistency with the analytical beam trajectory results.

lens

designs

consistency

beam


Input: Experiments are conducted using a PA2200 nylon lens bonded to an aluminum plate to demonstrate wave focusing and enhanced energy harvesting within the 3D-printed GRIN-PCL domain.

nylon

aluminum

lens

energy harvesting

domain


Input: The results show that 3D printing can provide a simple and practical method for implementing phononic crystal concepts with minimal modification of the host structure.

3D printing

simple

structure


Input: The spatial orientation of an object on a 3D printing plate is a significant contributor to its printing time.

orientation

3D printing


Input: Thus, the speed of the 3D printing processes can generally be increased by using time-efficient object orientations.

3D printing

be

orientations


Input: This paper presents a novel method for speeding-up printing processes that employs maximally efficient orientations.

printing processes

orientations


Input: This method finds an orientation for the object that minimizes the number of disconnected components and the distance between the disconnected components that remain, thereby minimizing the time needed for the printer head to traverse empty areas.

orientation

components

components

printer

areas


Input: The method also considers the height of the printed object, its trapped volume, and the number of connected components in each layer.

volume

components

layer


Input: Our novel algorithm considers all four criteria, each weighted according to printer-specific and experimentally-obtained parameters.

algorithm

parameters


Input: Preliminary trials demonstrate that this methodology can decrease printing times on fused deposition printers to 45% of that of current state of the art algorithms.

methodology

fused deposition

algorithms

art


Input: Waveguides are important optical elements for sensing, illumination, artistic displays, integrated optical circuits, as well as teaching aids for demonstrating important optical phenomena.

optical elements

sensing

optical

optical

as

as


Input: However, despite the high demand, most optical materials are difficult to fabricate into desired shapes using state-of-the-art manufacturing technologies.

optical

materials

state-of-the-art

fabricate

manufacturing technologies


Input: This paper presents a novel method for 3D printing customizable optics with a soft and stretchable (over 100% elastic strains) thermoplastic polymer.

3D printing

optics

stretchable

elastic

thermoplastic polymer


Input: To showcase the versatility of this approach, several applications were demonstrated, including unique artistic illumination, caustic patterns, beam splitter and combiner on both planar and 3D conformal surfaces, and optical encoder.

beam

optical encoder

surfaces


Input: The simplicity of the fabrication process, low-cost, excellent optical properties, and flexibility provide an attractive pathway for fabricating integrated optical devices and new opportunities for controlling light.

fabrication

fabricating

optical properties

flexibility

optical


Input: (c) As-printed waveguide splitter and combiner circuit on a 3D printed dome surface, and (d) Top view of lighted circuited.

c

3D printed

surface


Input: (e) Pattern of our group name “AM3 Lab” on a black paper substrate, and (f) Lighted with different LEDs.Download: Download high-res image (296 Inkjet printing has been used as an Additive Manufacturing (AM) method to fabricate three-dimensional (3D) structures.

Pattern

high-res image

substrate

as

f

Inkjet printing

Additive Manufacturing

AM

fabricate


Input: However, a lack of materials suitable for inkjet printing poses one of the key challenges that impedes industry from fully adopting this technology.

materials

technology

inkjet printing

industry


Input: Consequently, many industry sectors are required to spend significant time and resources on formulating new materials for an AM process, instead of focusing on product development.

industry

materials

product development

AM process


Input: To achieve the spatially controlled deposition of a printed voxel in a predictable and repeatable fashion, a combination of the physical properties of the ‘ink’ material, print head design, and processing parameters is associated.

deposition

voxel

predictable

fashion

parameters

physical properties

ink

material

print head

design


Input: Use of a liquid handler containing multi-pipette heads, to rapidly prepare inkjet formulations in a micro-array format, and subsequently measure the viscosity and surface tension for each in a high-throughput manner is reported.

inkjet

viscosity

surface tension


Input: The throughput is 96 formulations per 13.1 working hours, including sample preparation and subsequent printability determination.

throughput

sample

printability


Input: The HTS technique was validated by comparison with conventional viscosity and surface tension measurements, as well as the observation of droplet ejection during inkjet printing processes.

viscosity

surface tension

as

as

droplet

inkjet printing processes


Input: Using this approach, a library of 96 acrylate/methacrylate materials was screened to identify the printability of each formulation at different processing temperatures.

materials

printability

temperatures


Input: The methodology and the material database established using this HTS technique will allow academic and industrial users to rapidly select the most ideal formulation to deliver printability and a predicted processing window for a chosen application.

methodology

predicted

material

database

industrial

printability


Input: Controlling cooling airflow is feasible in FFF process for enhancing performance.

cooling

FFF

performance


Input: Cooling airflow has opposite influence on geometric quality and mechanical strength.

Cooling

quality

mechanical strength


Input: Void and crystallinity of printed PLA model are influenced by the airflow cooling.

Void

model

PLA

cooling


Input: The dimensional quality and mechanical properties of a fused filament fabrication (FFF) -printed 3D model are influenced by several process parameters.

quality

mechanical properties

process parameters

fused filament fabrication

FFF

3D model


Input: A forced-air cooling system that moves along with the print head was designed and installed on a commercial 3D FFF printer to control the cooling of the printed model.

cooling

cooling

print head

printer

designed

model


Input: The quality of the printed polylactide (PLA) model, including the dimensions and mechanical properties, was investigated for different cooling air velocities.

quality

model

mechanical properties

PLA

dimensions

cooling


Input: It was found that the cooling air velocity had different influences on the dimensional quality and mechanical strength of the printed model.

cooling

quality

model

mechanical strength


Input: More specifically, higher cooling speeds generated better geometric accuracy but lower mechanical strength.

cooling

accuracy

mechanical strength


Input: With the highest and lowest cooling air speeds of 5 m/s and 0 m/s, respectively, the tensile strengths of the printed models differed by 4-fold.

cooling

tensile strengths


Input: In order to determine a suitable cooling air velocity setting for each specific printing material, a design model was proposed.

cooling

material

design


Input: The determined printing parameters were employed in the fabrication of a Rubik’ s cube, as an example.

parameters

cube

fabrication

s

as


Input: The assembled cube demonstrated satisfactory performance both in the dimensional quality and in the mechanical function.

cube

performance

quality

mechanical


Input: Therefore, the cooling air velocity can be employed as an additional control parameter in 3D printing for a specified model.

cooling

3D printing

be

as

parameter

model


Input: Material extrusion additive manufacturing is widely used for porous scaffolds in which polymer filaments are extruded in the form of log-pile structures.

Material extrusion additive manufacturing

extruded

porous scaffolds

polymer filaments


Input: These structures are typically designed with the assumption that filaments have a continuous cylindrical profile.

designed

filaments

cylindrical


Input: However, as a filament is extruded, it interacts with previously printed filaments (e.g.

as

filament

filaments

extruded


Input: on lower 3D printed layers) and its geometry varies from the cylindrical form.

3D printed

geometry

cylindrical


Input: No models currently exist that can predict this critical variation, which impacts filament geometry, pore size and mechanical properties.

variation

mechanical properties

filament

pore size


Input: Therefore, expensive time-consuming trial-and-error approaches to scaffold design are currently necessary.

trial-and-error

scaffold

design


Input: Multiphysics models for material extrusion are extremely computationally-demanding and not feasible for the size-scales involved in scaffold structures.This paper presents a new computationally-efficient method, called the VOLume COnserving model for 3D printing (VOLCO).

material extrusion

3D printing

scaffold

VOLume

model


Input: The VOLCO model simulates material extrusion during manufacturing and generates a voxelised 3D-geometry-model of the predicted microarchitecture.

model

predicted microarchitecture

material extrusion

manufacturing


Input: The extrusion-deposition process is simulated in 3D as a filament that elongates in the direction that the print-head travels.

process

filament


Input: For each simulation step in the model, a set volume of new material is simulated at the end of the filament.

simulation

model

set

material

filament


Input: When previously 3D printed filaments obstruct the deposition of this new material, it is deposited into the nearest neighbouring voxels according to a minimum distance criterion.

3D printed

deposition

voxels

material


Input: This leads to filament spreading and widening.Experimental validation demonstrates the ability of VOLCO to simulate the geometry of 3D printed filaments.

filament

validation

geometry

3D printed


Input: In addition, finite element analysis (FEA) simulations utilising 3D-geometry-models generated by VOLCO demonstrate its value and applicability for predicting mechanical properties.

finite element analysis

mechanical properties

simulations


Input: The presented method enables structures to be validated and optimised prior to manufacture.

be

manufacture


Input: Potential future adaptations of the model and integration into 3D printing software are discussed.

model

3D printing


Input: A new stitching algorithm that self-adapts to the object geometry is introduced.

algorithm

geometry


Input: For slender objects, printing time can be reduced by 25% with the new algorithm.

be

algorithm


Input: An inevitable trade-off between resolution and total size exists when 3D printing objects.

resolution

3D printing


Input: While it is capable of reaching a sub-micron feature size, it needs to combine a high precision movement mechanism with a lower precision one when writing centimetric size objects.

sub-micron

feature size

precision

precision

mechanism


Input: As is demonstrated on a winding microfluidic channel, this can lead to substantial manufacturing time gains of up to 25%.

As

lead

winding

channel

manufacturing


Input: In this paper, a non-conventional way of additive manufacturing, curved-layered printing, has been applied to large-scale construction process.

additive manufacturing

construction


Input: Despite the number of research works on Curved Layered Fused Deposition Modelling (CLFDM) over the last decade, few practical applications have been reported.

research

Fused Deposition


Input: The method was evaluated with the 3D Concrete Printing process developed at Loughborough University.

Printing process


Input: The evaluation of the method including the results of simulation and printing revealed three principal benefits compared with existing flat-layered printing paths, which are particularly beneficial to large-scale AM techniques: (i) better surface quality, (ii) shorter printing time and (iii) higher surface strengths.

simulation

AM techniques

surface quality

surface

strengths


Input: Despite the enormous potential of additive manufacturing in fabricating three-dimensional battery electrodes, the structures realized through this technology are mainly limited to the interdigitated geometries due to the nature of the manufacturing process.

additive manufacturing

fabricating

manufacturing process

battery

technology

geometries


Input: This work reports a major advance in 3D batteries, where highly complex and controlled 3D electrode architectures with a lattice structure and a hierarchical porosity are realized by 3D printing.

lattice structure

porosity

3D printing


Input: Microlattice electrodes with porous solid truss members (Ag) are fabricated by Aerosol Jet 3D printing that leads to an unprecedented improvement in the battery performance such as 400% increase in specific capacity, 100% increase in areal capacity, and a high electrode volume utilization when compared to a thin solid Ag block electrode.

electrodes

truss

electrode

electrode

porous

fabricated

capacity

capacity

3D printing

battery

as


Input: Further, the microlattice electrodes retain their morphologies after 40 electrochemical cycles, demonstrating their mechanical robustness.

electrodes

morphologies

electrochemical

mechanical


Input: These results indicate that the 3D microlattice structure with a hierarchical porosity enhances the electrolyte transport through the electrode volume, increases the available surface area for electrochemical reaction, and relieves the intercalation-induced stress; leading to an extremely robust high capacity battery system.

structure

electrochemical

capacity

porosity

stress

electrolyte

battery

electrode

surface area


Input: Results presented in this work can lead to new avenues for improving the performance of a wide range of electrochemical energy storage systems.

lead

performance

electrochemical

range


Input: Pores are common defects in the process of directed laser deposition (DLD) which not only greatly reduce the fracture toughness of ceramic materials, but also lead to the failure of shaped parts.

Pores

defects

process

deposition

fracture

failure

laser

ceramic materials

lead


Input: In this paper, the formation mechanism of pores was analyzed and the effects of laser power, feeding rate, scanning speed and ultrasonic power on pores were investigated.

mechanism

pores

pores

laser power

scanning speed

power


Input: Transmission electron microscope, scanning electron microscopy observation and X-ray diffraction analysis were carried out for sample microstructure and phase composition respectively.

Transmission electron microscope

scanning electron microscopy

X-ray diffraction analysis

sample

microstructure

phase composition


Input: The relative density of samples was measured by the progressive focused ion beam and the porosity was calculated by image processing software Image.

relative density

porosity

samples

ion

image

software Image

beam


Input: The results show that the pores are divided into gas holes and shrinkage cavities.

pores

gas

shrinkage


Input: The appearance of circular gas holes with smooth inner walls are caused by the feeding method by gas forced blowing, the gas mixed with powder itself, and the gas in the molten pool formed by gasification of low-melting impurities and alumina/zirconia during laser processing.

gas

gas

gas

gas

molten pool

laser processing

blowing

powder

impurities


Input: The gas holes are evenly distributed in the cross-section of the thin-walled specimen parallel to the scanning speed.

gas

scanning speed


Input: As the temperature changes drastically, the material around the melt solidifies first, the melt will be attached to the solidified material to shrink, so that the melt can not be filled as a solid and finally the shrinkage cavities are formed.

As

material

be

material

be

as

temperature

melt

melt

melt

shrinkage

shrink


Input: Generally the shrinkage cavities are irregular and the pore wall is relatively rough, mainly concentrated on the top of thin-walled samples.

shrinkage

samples

pore


Input: The laser power has the greatest influence on the pores, which has the greatest effect on the porosity but little effect on the shrinkage cavities.

laser power

pores

porosity

shrinkage


Input: When the ultrasonic power is 180 W, the porosity reaches a minimum of 0.1±0.05% and the relative density is 99.9±0.1%.

power

porosity

relative density


Input: Traditional three-dimensional (3D) bioprinting techniques of reactive materials usually include a mixing step of reactive agents prior to deposition, leading to potential changes in the rheological and biocompatibility properties of the resulting ink.

three-dimensional

mixing

deposition

bioprinting

reactive materials

ink

rheological

biocompatibility


Input: During intersecting jets printing, reactive materials are dispensed separately, colliding and mixing with each other in air before landing on a previously deposited layer.

reactive materials

mixing

deposited layer


Input: While this enables reactive material printing using a printing-then-mixing approach, the resulting excess fluid may compromise the printing quality and accuracy.

reactive material

fluid

quality

accuracy


Input: This study aims to improve the performance of intersecting jets–based reactive material printing by introducing a stainless-steel wire mesh and fibrous tissue paper–based liquid-absorbing system, which functions as a method to remove the excess resultant liquid from the printing zone.

performance

reactive material

as

fibrous


Input: By selecting a proper wire mesh, the proposed liquid-absorbing system can absorb up to 65–90% of the excess liquid (water herein) resulting from printing aqueous reactive sodium alginate and calcium chloride inks, which are selected as model materials in this study.

sodium

alginate

calcium

as

materials


Input: By controlling the tilt angles of intersecting jets, the incident angle of post-collision droplets is desirable to be less than 14° to avoid droplet bouncing on the top of a previously deposited layer during 3D bioprinting.

tilt angles

droplets

droplet

be

deposited layer

3D bioprinting


Input: Using the liquid-absorbing system, different 3D structures have been successfully printed using intersecting jets printing.

3D structures


Input: For tubular alginate constructs printed in air from sodium alginate and calcium chloride inks, a 2.5 height-diameter ratio can be achieved.

tubular

alginate

sodium

alginate

calcium

be


Input: The proposed printing technology does not influence the post-printing cell viability while printing 3T3 cells, demonstrating its promising potential for bioprinting applications.

printing technology

cell viability

cells

bioprinting


Input: Methodology and challenges of 3D printing repairs outlined.

Methodology

3D printing


Input: Repeatable geopolymer temperature sensor presented.

temperature

sensor


Input: Adhesion strength between printed patch and concrete substrate 0.6 MPa.

Adhesion

concrete

MPa


Input: This paper addresses this issue by outlining, for the first time a 3D printable temperature sensing repair for concrete.

temperature

sensing

concrete


Input: The multifunctional material used in this study is a geopolymer: a durable alternative to ordinary Portland cement repairs, which can be electrically interrogated to act as a sensor.

material

cement

be

as

sensor


Input: In this paper, we outline the material and 3D printing process development, and demonstrate 3D printed repair patches with a temperature sensing precision of 0.1 °C, a long-term sensing repeatability of 0.3 °C, a compressive strength of 24 MPa, and an adhesion strength to concrete of 0.6 MPa.

material

concrete

3D printing

3D printed

temperature

sensing

sensing

precision

repeatability

MPa

MPa

compressive strength

adhesion


Input: The work demonstrates the feasibility of using additive manufacturing as a new means of applying repairs to concrete substrates, and provides one clear pathway to removing some of the barriers to the field deployment of multifunctional materials in a civil engineering context.

feasibility

materials

additive manufacturing

concrete

engineering


Input: The process shown here could enhance the design versatility of self-sensing repairs, unlock remote deployment, and de-cost and de-risk actions that prolong the lifespan and performance of existing concrete structures.

process

performance

design

concrete


Input: Brittle polymers suffer from the lack of stretchability, which limits their application when large deformation is required.

Brittle

stretchability

limits

deformation


Input: To address this limitation, we investigate the stretchability of a set of cellular materials with conventional and novel cell architectures through 3D printing, experimental testing, and computational simulation.

stretchability

set

cell

cellular materials

3D printing

experimental

simulation


Input: The presence of sharp corners restricts the stretchability of the honeycomb and arrowhead cellular architectures.

stretchability

honeycomb


Input: A new class of accordion-like cellular architecture with sinusoidal struts is designed to enhance the planar stretchability of cellular solids.

architecture

struts

designed

stretchability


Input: These accordion-like sinusoidal architectures exhibit an enhancement in the stretchability of the cellular materials even for those samples fabricated from brittle polymers.

stretchability

cellular materials

samples fabricated

brittle


Input: The manufacturability of the proposed architectures is demonstrated utilizing SLA and FDM additive manufacturing techniques.

manufacturability

SLA

FDM additive manufacturing techniques


Input: We customize the 3D printing settings to fabricate specimens with tailored architectures for experimental testing.

3D printing

fabricate

experimental


Input: Comparing the stress-strain curves obtained by experimental testing on the 3D printed samples with numerical simulation confirms that the failure strains for sinusoidal architectures can be as high as 20 times that of conventional honeycombs without compromising the energy absorption efficiency of the cellular materials.

experimental

failure

3D printed

numerical simulation

be

as

as

cellular materials

energy absorption


Input: The stress-strain curves for 3D printed samples fabricated from flexible polymers are presented to show that energy dissipation in a hysteresis loop also can be enhanced by exploiting the accordion-like sinusoidal architectural designs.

3D printed

fabricated

polymers

be

hysteresis loop

designs


Input: The sinusoidal struts in accordion-like cellular architectures offer a design route to extend the material property chart to achieve ultrahigh stretchability in lightweight 3D printable brittle and flexible polymers for applications that require combined stretchability, lightweighting, and energy absorption such as soft robotics, stretchable electronics, and wearable protection shields.

struts

stretchable electronics

design

stretchability

stretchability

material property

lightweight 3D

brittle

lightweighting

polymers

as

energy absorption

robotics


Input: In additive construction, ambitious goals to fabricate a concrete building in less than 24 h are attempted.

additive

concrete

fabricate


Input: This analysis included a study of the variation in comprehensive layer print times, expected trends and forecasting for what is expected in future prints of similar types.

variation

trends

layer


Input: Furthermore, the study included a determination and comparison of print time, elapsed time and construction time, as well as a look at the effect of environmental conditions on the delay events.

print

construction

as

as


Input: Upon finishing, the analysis concluded that the 3D printed building was completed in 14-hours of print time, 31.2-hours elapsed time, or a total of 5 days of construction time.

finishing

3D printed

print

construction


Input: Anisotropy of mechanical properties and support material removing are the two main problems when fabricating 3D lattice structures by integrated printing via additive manufacturing (AM) technology.

Anisotropy

mechanical properties

technology

support material

fabricating

additive manufacturing

AM


Input: Aiming at these two problems, a snap-fit method is introduced into PolyJet technology to fabricate polymer lattice structures with four typical configurations, namely BCC, BCC-Z, FCC and octet.

snap-fit

lattice structures

PolyJet

BCC

FCC

fabricate


Input: Uniaxial compression tests indicate that both the strengths and energy absorptions of the four kinds of snap-fitted lattices are increased by over 100% compared to the integrated counterparts.

compression tests

energy absorptions

strengths

lattices


Input: The effect of strut thickness on compressive responses of the snap-fitted and integrated lattices is investigated.

strut thickness

lattices


Input: With the decrease of strut thickness, the advantage in the strength of the snap-fitted lattices becomes more obvious compared to the integrated counterparts.

strut thickness

strength

lattices


Input: Ideal maximum strength models based on yield, elastic buckling and inelastic buckling are developed and are able to predict the compressive peak strengths of the snap-fitted PolyJet lattices.

strength

elastic buckling

buckling

strengths

PolyJet lattices


Input: This study opens up an avenue for the fabrication of large scale 3D printed lattice structures with optimal mechanical properties and without support material removing problem.

fabrication

3D printed

mechanical properties

support material


Input: This paper aims to study the mechanical properties of mixed isotropic carbon fiber 3D printed composites and further investigates the influence of hot press on the [0°/45°/90°] 2 fiber angles composite with varying temperature, pressure and time.

mechanical properties

investigates

pressure

isotropic carbon fiber

fiber

composite

3D printed

press

temperature


Input: Tensile tests, autoclave treatment and microstructural observation were utilized to characterize the composites.

Tensile tests

microstructural observation

autoclave

composites


Input: Results revealed that the [0°/45°/90°] 2 performed the highest tensile strength of 79 MPa and modulus of 3.51 GPa, compared to [30°/45°/60°] 2 and [15°/45°/75°] 2.

tensile strength

GPa

MPa


Input: This is due to the fibers along the tensile axis angle that bears maximum load in longitudinal direction.

fibers

tensile


Input: At 200 °C temperature, the hot pressed composites presented the highest tensile strength of 98 MPa and modulus of 3.93 GPa than non-hot pressed.

temperature

hot pressed

pressed

composites

tensile strength

GPa

MPa


Input: Increased temperature caused better interface wettability between fibers and matrix.

temperature

interface

fibers


Input: At 200 kPa pressure, the hot pressed composites showed the highest tensile strength of 100 MPa and modulus of 4.06 GPa than non-hot pressed.

pressure

MPa

hot pressed

pressed

composites

tensile strength

GPa


Input: Further increased pressure resulted in lower tensile strength and modulus, as the material became stiffer pushing more matrix material to side leaving numerous fibers unbounded by the matrix.

pressure

tensile strength

as

material

material

fibers


Input: For 30 min withholding time, the hot pressed composites indicated the highest tensile strength of 106 MPa and modulus of 4.27 GPa than non-hot pressed.

hot pressed

pressed

composites

tensile strength

GPa

MPa


Input: Increased time caused strongest interface bonding by removing the air gaps induced during printing between fibers and matrix.

interface bonding

fibers


Input: Results revealed that hot press significantly improved the mechanical properties of carbon fiber 3D printed composites.

press

mechanical properties

carbon fiber

3D printed


Input: To realize the full potential of 3D Printing technology in the design of materials and structures, it is indispensable to characterize and predict the mechanical response of 3D Printing materials to external stimuli.

3D Printing technology

design

materials

mechanical response

external stimuli

3D Printing


Input: This study is focused on hyperelastic strain measurements and constitutive parameters identification of 3D printed soft polymers undergoing uniaxial deformation.

strain

parameters

deformation

3D printed

polymers


Input: A simple method using an optical camera in conjunction with an image processing tool is proposed to accurately measure the average strain experienced by rubbery polymers during a tensile test.

simple

optical

accurately

tensile test

camera

tool

image

average

polymers


Input: The potential of the method is demonstrated through tensile tests of 3D printed soft polymer by accurately determining the stress–strain response and the Poisson's ratio without using extensometers.

tensile tests

accurately

3D printed

polymer


Input: Influence of printing direction on the anisotropic behavior of 3D printed polymer is investigated by applying the proposed test method to specimens printed in two different directions.

anisotropic

3D printed


Input: The Neo-Hookean constitutive parameters of the soft polymer are determined from the experimentally obtained stress–strain data.

parameters

data

polymer


Input: Moreover, finite element analysis (FEA) of the soft polymer is performed to show that the constitutive parameters determined can predict the mechanical response of the tested polymer accurately if used in commercial FEA packages.

finite element analysis

parameters

mechanical response

polymer

polymer

accurately


Input: The additive manufacturing of structural composites is a disruptive technology currently limited by its moderate mechanical properties.

additive manufacturing

composites

technology

mechanical properties


Input: Continuous fibre reinforcements have recently been developed to create high performance composites and open up encouraging prospects.

fibre

composites

performance


Input: In addition, to apply these materials to engineering applications, it is of high importance to evaluate the effect of environmental conditions on their mechanical performances, particularly when moisture-sensitive polymer is used (PolyAmide PA for instance) which is currently lacking in the literature.This present article aims to investigate in more detail the relationship between the process, the mechanical behaviour and the induced properties of continuous carbon and glass fibres reinforced with a polyamide matrix manufactured using a commercial 3D printer.

materials

process

mechanical behaviour

properties

manufactured

engineering

mechanical

polymer

PolyAmide

carbon

glass fibres

polyamide

PA

3D printer


Input: In addition, their hygromechanical behaviour linked to moisture effect is investigated through sorption, hygroexpansion and mechanical properties characterization on a wide range of relative humidity (10–98% Relative Humidity RH) .The printing process induces an original microstructure with multiscale singularities (intra/inter beads porosity and filament loop).

mechanical properties

microstructure

range

RH

filament

printing process

beads


Input: Longitudinal tensile performance shows that the reinforcing mechanism is typical of composite laminates for glass and carbon.

tensile

performance

mechanism

composite

glass

carbon


Input: However, the rather poor transverse properties are not well fitted by the Rule Of Mixture (ROM), thus underlining the specificity of the printing-induced microstructure and an anisotropic behaviour in the material.Non-negligible (5–6%) moisture uptake is observed at 98% RH, as well as orthotropic hygroscopic expansion of PA/carbon and PA/glass composites.

properties

Rule Of Mixture

microstructure

anisotropic

hygroscopic

RH

as

as

composites


Input: The consequences of various moisture contents on mechanical properties are studied, showing a reduction of PA/carbon stiffness and strength of 25 and 18% in the longitudinal direction and 45 and 70% in the transverse direction.

mechanical properties

reduction

stiffness

strength


Input: For PA/glass composites, we obtain a reduction in strength of 25% in the longitudinal direction, along with a 80% reduction of stiffness and 45% in strength in the transverse direction.

composites

reduction

reduction

strength

stiffness

strength


Input: Fused Filament Fabrication (FFF) is one of the most popular 3D printing processes that can be used to manufacture flexible parts.

Fused Filament Fabrication

FFF

3D printing

be

manufacture


Input: In this work, we investigate the impact of stacking sequence, slit size, and thickness on the tensile properties of 3D printed flexible kirigami specimens.

impact

tensile properties

3D printed


Input: In addition, we demonstrate how the transition phenomenon and out-of-plane deformation can significantly improve percent elongation at their breaking point.

transition

deformation

elongation


Input: Considering the deformed shape during testing, specimens with a combination of layers printed along and transverse to their length showed the highest tensile break strength and the percent break elongation (2.43 MPa and 183%, respectively).

deformed shape

tensile

strength

elongation

testing

MPa


Input: It is also determined that the occurrence of the transition phenomenon depends on the specimen’ s thickness, and was observed for the 1 mm and 1.5 mm thick samples.

transition

samples

s

mm

mm


Input: The heating of a polymer in a liquefier of a material extrusion 3D printer is numerically studied.

heating

material extrusion 3D printer

polymer


Input: The polymer is taken as a generalized Newtonian fluid with a dynamical viscosity function of shear rate and temperature.

polymer

as

Newtonian fluid

viscosity

temperature


Input: The system of equations is solved using a finite element method.

finite element method


Input: The boundary conditions are adapted by comparison with the previous work of Peng et al.

boundary conditions

al


Input: [5] showing that the thermal contact between the polymer and the liquefier is very well established.

contact

polymer


Input: The limiting printing conditions are studied by determining the length over which the polymer temperature is below the glass transition temperature.

polymer

glass transition temperature


Input: This provides a simple relation for the inlet velocity as a function of the working parameters and the polymer properties.

simple

inlet

as

polymer

parameters


Input: The use of 3D printing technologies enhanced with component placement and electrical interconnect deposition enables electronic systems with freedom in fabrication and complex embedded circuitry.

3D printing technologies

component

electrical

deposition

fabrication


Input: However, with more electrical functionality being integrated, new material requirements become increasingly important.

electrical

material


Input: This paper introduces a novel approach for processing adhesives with an extrusion-based UV-assisted 3D dispensing process.

adhesives

process


Input: A specimen study revealed promising results for three out of six adhesives (denoted as A, D, E), for which an extensive anisotropy evaluation was performed: The relationship between the layered construction strategy and the material properties of the printed parts was characterized by micrograph analysis, tensile testing along with fracture analysis and laser flash analysis.

adhesives

as

flash

anisotropy

construction

material properties

fracture

tensile testing

laser


Input: An exemplary study for one adhesive via tensile testing showed no significant difference between three printing orientations.

adhesive

tensile testing

orientations


Input: However, different construction strategies influenced the degree of anisotropy.

construction

anisotropy


Input: In addition, the evaluation of thermal anisotropy revealed a link between the thermal conductivity and the rate of the UV-curing for A and D. For material E, no significant difference was measured.

anisotropy

thermal conductivity

material