Plastics News Europe - September 2019 - 20

additive manufacturing

➡ Continued from page 19
effect on the mechanical performance of the components. Autoclaved components show the highest
strength and stiffness compared to
parts produced with other manufacturing technologies.
In polymer additive manufacturing
processes using composite materials,
parts are built up layer by layer using
some source of thermal energy to
weld the layers together. Studies have
shown, however, that interlayer adhesion and consolidation can be
problematic, with the occurrence of
pore and voids that can reduce material integrity and therefore weaken
the mechanical performance.
The polymer DED process developed by Arevo results in better interfacial adhesion with significantly
higher fibre volume content. During

the process, a laser is used to melt the
filament. Then, a compaction roller
provides sufficient pressure to compress the filament and bond it to the
substrate layers, eliminating the voids
inside and in between the layers, and
consolidating the parts in-situ. The
entire deposition system is mounted
on a six-axis robot, allowing the deposition in any angle and direction.
Material deposition is controlled in a
closed loop and can be tailored to any
given material and geometric feature.
In the foregoing, the lack of reliable material data was referred to as
one of the significant obstacles to the
use of AM with composites for structural parts. The DED process has been
studied comprehensively and found
to be in good agreement with mechanical data for similar fibre and matrix materials, fibre contents and layups found in composite literature.

Recent tests have shown that performance is comparable to thermoplastic composite parts manufactured in
the autoclave.
Furthermore, in comparison to autoclave and other traditional process
technologies, the DED process allows
in-situ consolidation of the thermoplastic composite parts with good interfacial adhesion due to direct heating at the interfaces. At the same
time, the process enables complex
features only possible with AM technologies. These include, for example,
hollow sections such as box beams,
thin, curved walls and overhangs, as
recently demonstrated in a 3D printed bike frame using the technology.
This article is based on a paper
originally presented at the SAMPE
2019 Conference and Exhibition.
See http://bit.ly/2TD11PX

3d printed bicycles enter
the marketplace

ver the past few years, among the
products Arevo has targeted with its
additive manufacturing technology
have been bicycles. The company partnered
with Oechsler, a manufacturer of automotive and medical parts, on the development
of the first 3D printed eBike featuring a 3D
printed carbon fibre frame and equipped
with Oechsler's Drivematic three-speed automatic gearbox. The bike launched last
year, can be customised for individual riders, printed as and when needed at scale,
and competitively manufactured anywhere
in the world - "significantly cutting down
on the process and time it has taken historically to create bike frames," Hemant Bheda, Arevo co-founder and chairman said.
"We have created a new paradigm for
manufacturing that empowers businesses

to create and source products locally by leveraging advancements in dynamic software
and automation," he added.
Since that first project, Arevo has gone
on to collaborate with boutique bike manufacturer Franco Bicycles on the commercial
production of the world's first 3D printed,
continuous carbon fibre single-piece unibody frame for a new line of e-Bikes that
Franco will sell under the "Emery" brand.
The Arevo frame, enabled by the company's
proprietary AM technology, is made as a single part, in contrast to current composite
frames, which are made of many parts
glued together, and it is this production
method that provides its excellent structural
integrity and stability.
The technology offers numerous advantages, including true 'lights-out', serial, volume

Emery bike featuring the first 3D printed, continuous carbon fibre
single-piece unibody frame

Arevo 3D printed composite
bike frame
production of AM-made composite parts
that are made with thermoplastic materials,
which are tougher, durable and recyclable,
as compared to brittle and non-recyclable
thermoset materials. It also offers a far
greater "freedom of design" creates the
possibility of fully-customised bikes made
on an "on demand" basis, an approach
Arevo calls "DESIGN. PRINT. GO."
As Hemant Bheda said: "With the introduction of the Emery One, the transformation of the global composite bike industry has begun."
The frames are in production now at
Arevo's multi-purpose facility in Milpitas.
Arevo has also announced it will be introducing a new frame design at Eurobike
2019, taking place September 4-7 in Friedrichshafen, Germany, once again at the
Oechsler stand.

september 2019

http://www.bit.ly/2TD11PX

Plastics News Europe - September 2019

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