JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - o - 47

A new light on composites heating

to current industrial challenges. One of the
most important benefits is that although the
system is very powerful, operators are able
to remain next to the AFP equipment while
it is running. This is because the technology,
based on the flashlamp, does not have the
same health and safety requirements as a laser-based system (where operators typically
have to retreat to a protective booth while
lay-up is being carried out). So it can provide
the lay-up capabilities of a laser in a realistic
production environment.

Fig. 2: Position of the lamp housing and light guide

Fig. 3:
a) A close-up image of the
technology laying up the first
ply of a dry fibre panel;
b) a thermal image of the
same geometry, showing
the energy concentrated at
the nip point

Successful trials
Heraeus Noblelight trialled humm3®
successfully on industrial AFP robotic
systems at the National Composites Centre
(NCC) in the UK and Coriolis in France.
Collaborations with both these partners were vital in the development of the
technology and in understanding the requirements of end users. At the NCC, a
comparison with IR and laser heating products showed that the technology is faster,
more powerful and more controllable than
IR lamps, meaning higher temperature ma-

terials such as dry fibre and thermoplastics
can be processed, while it is safer, smaller
and more easily scalable than a laser. A particular highlight of the trials has been achieving high-quality lay-up of Hexcel's HiTape®
dry carbon fibre material at speeds of up to
1 metre per second. As a result of demonstration events held at the NCC, there is
now a great deal of interest from potential
customers in humm3® technology as an alternative to laser heating.
The key messages from customers have been
clear - humm3® has many benefits relevant

A radically different heating method
A second advantage of humm3® is its rapid,
close temperature control. The time to reach
the required temperature is of the order of a
few microseconds and, as there is no residual
heat in the lamp due to water cooling, heating can be ramped down equally quickly.
The controllability of the technology comes
from the pulsed nature of the source. Rather
than heating a target material continuously,
as laser and IR lamps do, it imparts short-duration pulses of energy to the target that can
be closely controlled with three parameters
(pulse duration, pulse energy and pulse
frequency). This radically different way of
heating composites provides the opportunity to tailor surface and through-thickness
temperature profiles to suit the required
application. For example, on a convex part
with a sharp corner, the heating power can
be quickly reduced to match the slow layup speed around the corner before being
increased for the faster lay-up along flat sections (Figure 4).
Typically, humm3® technology uses a
frequency of above 60 pulses per second,
as the human eye cannot perceive flashing
at this frequency. Although the material is
experiencing many short pulses per second,
which combine to give the required thermal
profile, the operator only sees a continuous
light source, reducing problems of annoyance.
In collaboration with Coriolis in France,
Heraeus Noblelight has shown that the
smaller physical size of this technology,
when compared with the laser and its optics,
allows a greater range of complex geometries
to be laid-up, in particular geometries with

No111 March 2017

/ jec composites magazine

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