JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 24

MANUFACTURING 3D printing

Will composites be competitive
with metals in 3D printing?
The composites industry has a tendency to get caught off-guard by
metals as they make progress into more applications. 3D printing is
an area where metals have taken the lead, but a number of developing
technologies could put composites back on top.
MiChael ChaPiro
Chief strategy officer
Mantis Composites

omposites are often heralded as
the materials of the future. Their
strength properties offer an incredible advantage over any other material.
With the Boeing 787, Airbus A350, and
BMW i-series, composites are well on
their way to establishing a stronghold
in mainstream manufacturing.

However, the metal industry is still very
much a threat to the continued success
and growth of the composites industry.
Alcoa's 3rd generation of aluminiumlithium alloys has led many companies
to move away from composites, and
these alloys are slated for various new
aerospace projects. Considering that it
was only in the past few years that com-

Fig. 1: Strength and stiffness of traditionnal
composites compared to 3D printing

posites became viable in a large-scale
performance production line, these forward leaps in metals could pose a threat
to the increasing market penetration of
composites.
Metal 3D printing
3D printing is another area where metals compete with composites. Metal 3D
printing already works fairly well for a
variety of alloys, but by virtually any
metric, there is currently no 3D printing technology for composites that is
comparable in performance to the best
that metal 3D printing has to offer, let
alone something comparable to tape
laying. Research in metal 3D printing has been ongoing for the past decade, leading to multiple advances with
applications in aerospace and other
industries such as high-performance
automotive. Titanium 3D printers can
currently achieve comparable properties to machined titanium when using a
solid rod feedstock, and although these
parts require some degree of post-machining, they are proving effective for
intricate, high-strength parts. Selective
laser sintering (SLS) printers, which
use a powdered input material, eliminate this machining step making them
precise enough to use in components
such as fuel nozzles in CFM's LEAP engine, but the powder process has other
drawbacks such as porosity.

jec composites magazine / No108 October 2016

A true carbon fibre 3D printer should
be able to produce intricate, detailed,
and strong parts greatly surpassing the
capabilities of machined aluminium and
3D-printed metal at a cost that falls in
between the two, all while easily producing highly tailored properties along
with entirely new CFRP structures.
Composite feedstocks are less expensive
than the precisely powdered alloys used
in some metal 3D printers, and the energy required to heat a thermoplastic or
reactive polymer is much lower than the
energy required to fuse metal. This goal
has not yet been achieved due to limited
investment in this area and engineering challenges rather than any inherent
physical limitations.
Significant disadvantages
Several startups have developed various
systems to 3D print composite materials over the past few years, but all the
current approaches demonstrate significant disadvantages when compared
to machined aluminium, especially for
industrial applications. As a result, these
startups tend to focus on either consumer 3D printing or merely providing
geometric prototypes.
The material feedstock presents one of the
major limitations. Markforged, the makers of the first carbon fibre 3D printer, is
the only company currently offering a

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #108 - October 2016