Innovations in extrusion based additive

manufacturing technologies

Prof. Ludwig Cardon

Ghent, in the cultural and economical heart of Europe …

Mission statement

Ghent University wants to be a creative

community of staff, students and alumni,

connected by the values the university carries

out: engagement, openness and pluralism.

Our motto is Dare to Think: we encourage

students and staff members to adopt a critical

approach. Rector:

Professor Anne De Paepe

Established in 1817

Research: input

(Numbers: 2014)

Research expenditures 2014: € 265 million

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Public Research Funding - Regional and National Public Research Funding - EU and International Private Research Funding

Research lines

Prof. Ludwig Cardon

Prof. Kim Ragaert

Sustainableuse &

recycling

Post-industrial& post-

consumer

Mixed polymerstreams

Design for/fromrecycling

Advanced polymer

processing

Micro FibrillarComposites

Mould Engineering

Advanced extrusion

Additive Manufacturing

Polymers & composites

Extrusionbased

Fablab UGent

Known as FDM - Fused Deposition Modelling (Stratasys)

3D Plotter & BioScaffolder

Several types of low cost printers

Polymers

Composites

Ceramic and metal slurries

Extrusion based Additive Manufacturing

8

Extrusion based Additive Manufacturing

Towards 3D Printing of composites

and new materials?

“Nasa’s next Rover

has 3D-printed parts”

Resin infusion

Spray-up

Filament winding

To understand the process it may be useful to study a traditional

screw-fed extrusion process

Viscosity =

Share rate (speed) =

Shear stress =

Processing methodology

Processing methodology

Shear stress

.D / 4L

shear stress in N/mm²

pressure drop in N/mm²

D diameter of tube in mm

L length of tube in mm

Shear rate (speed)

=32Q / D³

average shear rate in s-1

Q output in mm³ s-1

D diameter of the tube in mm

Anisotropy between « layers and filaments»

Intermediate mechanical properties

Limited dimensional accuracy (stair-step effect)

Available materials

Poor interlayer bonding

Warpage and thermal stresses

Solidification process and shrinckage

Processing limitations

Processing limitations

Extrusion based Additive Manufacturing

Ongoing research

New printing heads and build strategies

for extrusion based AM technologies

Technical applications

Medical applications

Composite applications

Materials

New compounds and fillers

Improving the mechanical properties of AM composite materials

(bonding matrix and particles/fibres)

Dimensional accuracy (shrinkage)

Use “anisotropy as an advantage”

Composite materials for AM

Particle filled polymers for

enhanced stiffness, wear

resistance, thermal and

electric properties.

[1]: Nikzad, M., S. H. Masood, and I. Sbarski, 2011, Thermo-mechanical properties of a highly

filled polymeric composites for Fused Deposition Modeling, Materials & Design, v. 32, p. 3448-

3456

[2]: Ozkoc, G., G. Bayram, and E. Bayramli, 2005, Short glass fiber reinforced ABS and

ABS/PA6 composites: Processing and characterization: Polymer Composites, v. 26, p. 745-755

[3]: Markforg3D, Mark One, carbon fibre sample

Short fibre filled

polymers for higher

stiffness and wear

resistance.

Continuous fibre

composite for higher

stiffness, tensile and

impact strength.

Extrusion based Additive Manufacturing

High-end short fibre filled materials

Arevo labs

PEEK, PAEK, PPSU + short carbon - glass fiber fibre - CNT

(ArevoLabs, 2016)

Extrusion based Additive Manufacturing

Short fibre thermoset 3D Printing

Extrusion of short fibres containing epoxy

Syringe based, high accuracy

UV-curing after deposition

Printing of open structures

(Harvard, 2014)

Extrusion based Additive Manufacturing

Discontinuous fibre filled materials

ORNL labs (Oak Ridge National Laboratory,

Cincinnati Incorporated)

3D Printing of large volume parts with

discontinuous carbon fibre filled ABS

Carbon particles of 6-7 µm diameter

The parts have an improved stiffness of

5/6 times compared with unfilled polymers.

(Strati, ORNL, 2014)

M., R., Talagani, et al., 2016, Numerical

Simulation of Big Area Additive

Manufacturing (3D Printing) of a Full Size

Car , SAMPE 51 No.4

Extrusion based Additive Manufacturing

Coated filament materials

Texas Tech University

Carbon NanoTubes coated filaments

Improving the adhesion between layers

due to local heating of the layers via microwave heating

Extrusion based Additive Manufacturing

Continuous fibre filled materials

2,5D deposition of glass, carbon or aramid continuous fibre prepreg in a polyamide matrix

First continuous fibre “printed” part, “tailoring” fibre direction possible

Enhanced stiffness and strength compared to unfilled polymer

Curved Layer AM @UGent

Deposition normal to a surface

Better surface quality

Anisotropy can be used as an advantage

Faster printing of curved surfaces

Printing on existing objects

Van De Steen W., Ragaert K., Degrieck J., Cardon L.; Ghent University (2014)

The slicer creates a generic 5-axis

tool path which has to be followed

by the printhead to print the object.

This 5-axis tool path is modified

through a coordinate transformation

to compensate for the kinematic

properties of the specific 3D-printer

used. Lengths of the tool path

sections are calculated in order to

determine the necessary polymer

flow at each location on the tool

path.

Subsequently, the 3D-printer’s firmware

translates the 5-axis tool path

commands to actual signals to control

the motors that enable the print head to

make the corresponding movements.

This firmware is an advanced version of

an existing, open source firmware.

Unlike 3-axis 3D-printers, 5-axis

printers are able to print normally on a

complex surface on condition that the

print head does not collide with the

already printed part.

In future research, the development of

a custom made printing head will be

necessary for processing and

analysing new (composite) materials

for additive manufacturing. Existing

printing machines will have to be

adapted to give the printhead the

desired degrees of freedom.

(UGent, W. Van De Steene, S. Roegiers. L. Cardon, 2015)

Curved Layer AM – 5-axis 3D Printing @UGent

Advantages of a 5-axis 3D Printer:

More accurate and smoother surfaces

Better mechanical properties

Faster printing process

Less or no support structures required

Other – 5-axis 3D Printing

University of Oslo, Øyvind

Kallevik Grutle

(Øyvind Kallevik Grutle, 2015)

Parallel research at

Auckland University of Technology

Micro extruder AM technology @UGent

Additive manufacturing with a

microextruder

Increased production rates

compared to filament extrusion

Makes the extra step of filament

extrusion process obsolete

(UGent, M. Moerman, W. Van De Steene, L. Cardon, 2014)

Continuous Fibre AM technology @ UGent

Melt impregnation of continuous

glass fibres suitable for additive

manufacturing

This thermoplastic prepreg

production process is faster and

more efficient than powder

impregnation

Accurate pressure control is

necessary to guarantee complete

impregnation of the fibre bundle

(UGent, W. Van De Steene, L. Cardon et al, 2015)

26

The future?

Towards 3D Printing in space environment…

Spray-up

Contact information

Technologiepark 915

9052 Zwijnaarde

+32 9 331 03 91

Part of

Member of

Prof. dr. Ludwig Cardon

Head of CPMT

Characterization and 3D

Processing of Polymers

Additive Manufacturing of Polymers

ludwig.cardon@ugent.be

0478/224 335

Prof. dr. Kim Ragaert

Sustainable Use and Recycling of

Polymers & Composites

kim.ragaert@ugent.be

0476/322 700

Questions?