SAMPE Journal - November/December 2021 - 13

performance. To meet these requirements, CF3D®
development has been focused on UV curable
thermoset matrices because of their superior
mechanical and snap cure properties. Continuous
Composites
is
partnering
with
prominent
materials companies and customers to establish
a library of resins that work with CF3D®
. Through
,
Figure 2. Simplified CF3D
process diagram.
a Joint Development Agreement with Arkema®
custom polymer solutions are in development
to meet customer application requirements for
strength, modulus, glass transition temperature,
among other properties12
. In addition to traditional
polymers and composites, new photoinitiated
polymers are in development that convert
to
ceramic or carbon, allowing the creation of
Ceramic Matrix Composites (CMCs) and Carbon
Bonded Carbon (CBC) composites.
CF3D DEVELOPMENT
CF3D®
relies on three technology components
to achieve new functionality in composites
manufacturing. Research and development have
been conducted in hardware platforms, software,
and materials to support true three-dimensional
part generation that can leverage specific material
combinations to maximum effect.
Hardware Development
The hardware system consists of various motion
and active control packages, accommodating a
range of systems and build volumes and various
end effectors that conduct the entire print process.
A simplified process diagram of the CF3D®
end
effector is shown in Figure 2. Several versions of
end effectors and motion strategies have been
iterated to arrive at the current SOTA package.
Previous iterations of the CF3D®
end-effector
were comprised of a combination of mostly passive
control loops and proof of concept subsystems as
shown in Figure 3. After rigorous lab testing and
down-selection, the current version builds upon
previous iterations of the technology and the
current SOTA in automated additive composites
manufacturing. Real-time active controls are
present in each critical subsystem utilizing robust
industrial controllers, electronics, and mechanical
components.
CF3D®
's initial consumable is dry fiber (as
opposed to prepregs) or other continuous media
that is impregnated in the tool head with an
onboard resin system and compacted and cured
at the tool center point (TCP). Due to this process,
several new challenges were presented that are
atypical to previous manufacturing techniques.
Active control systems have been deployed to
control fiber tension, creel torque, alignment,
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NOVEMBER/DECEMBER 2021
|
SAMPE JOURNAL |
13
Figure 3. Previous iteration of CF3D End-Effector (Version 0.6).
fiber cross-section geometry, impregnation, feed
distances, cut positions, compaction, and cure
source dose. Particularly unique to the process is
a custom-designed accurate no-pulsation pump
system and hydrostatic impregnation module that
allows for accurate, consistent and user-specified
fiber volume fractions. After impregnation, several
fiber-handling subsystems direct, feed, clamp, cut
and deliver a wetted tow to the TCP. At the point
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SAMPE Journal - November/December 2021

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