JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - o - 46

MANUFACTURlNG AFP

A new light on composites heating

DR DAVID WILLIAMS
Composites Consultant

eraeus Noblelight, based in Cambridge
(UK), is recognised for excellence in
photonics technology, producing specialist lamps with wavelengths ranging from
ultraviolet to infrared for industrial, scientific
and medical applications. The company is a
world leader in manufacturing flashlamps -
high-energy, broadband, pulsed energy sources, typically used as the pumping source in a
solid-state laser. Its exciting new innovation
has been to design a system that uses the flashlamps as a direct heat source for composites -
humm3® technology (Figure 1).
The story started five years ago. Some detailed
initial research identified a gap in the market
for an improved automated fibre placement
(AFP) heating solution. Infrared (IR) lamps
were relatively slow to heat and cool, held sig-

Heraeus Noblelight introduces humm3® - an innovative heating
technology for composites manufacture. This technology has been
applied successfully to automated fibre placement, where its high
power, close control and safe operation are significant advantages over
current heating solutions.

nificant residual heat when switched off and
were not powerful enough to heat dry fibre or
thermoplastic materials. On the other hand,
lasers were powerful but physically large, limiting the geometric complexity of achievable
parts, and involved significant health and safety issues, with operators typically having to
retreat to a protective booth while lay-up was
being carried out. The conclusion was that industry needed a fast, powerful, safe and physically small AFP heating solution.
Inspired by the hummingbird
humm3® heating technology was developed
over the last five years, starting with a simple
prototype system for static heating in Heraeus
Noblelight's research laboratories and evolving to an optimised system suitable for fast and
controllable AFP lay-up. The name "humm"
is derived from a hummingbird, partly as the
technology shares its attributes of precision,
speed and continuity of movement, and partly because the blurring of the bird's wings in

Fig. 1: humm3® heating technology mounted onto an AFP robotic system at the National Composites Centre, UK

jec composites magazine / No111 March 2017

flight reflects the seemingly constant light
from the flash lamp (60 flashes per second).
The "3" represents its 3-programmable-parameter thermal control (duration, energy and
frequency).
The journey has been both challenging and
very rewarding. At the heart of humm3® is a
Xenon flashlamp - a quartz glass tube filled
with Xenon gas under pressure. When triggered under appropriate conditions, the gas
turns into a plasma to generate short-duration, broadband, high-energy pulses. These
pulses, either individually or as a continuous
sequence, are highly effective at heating composite materials.
This technology harnesses the power of the
Xenon flashlamp by placing it in a reflective
housing, with an aperture at the front to allow
the pulsed energy to be directed towards a target material. In order to guide the pulsed energy to the correct location, a solid, transparent
light guide is used, which acts like a large-scale
optical fibre, collecting the energy from the
flashlamp and concentrating it onto the required heat zone (Figure 2). For AFP applications, this is typically a 5-cm wide area near to
the nip point between the roller and substrate.
The end of the light guide can be engineered
and shaped to optimise the energy profile on
a substrate, allowing a wider or tighter heat
zone relative to the nip point. These effects are
captured using thermal imaging cameras
(Figure 3).

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - o