INTERVIEW INTERVIEW Professor Paul Richard Stein
Hague
ADDING VALUE
Nottingham University’s Centre for Additive Manufacturing
is taking 3D printing into the fourth dimension. Jon Excell
spoke to its director, Professor Richard Hague.
As director of one of the world’s
leading additive manufacturing
(AM) research groups Nottingham
University’s Professor Richard Hague
is a central figure in the global AM
research community.
As previously reported by The
Engineer, his team has played a key role in
advancing understanding of how to exploit the
design freedom enabled by additive techniques,
an understanding that has helped inform
industrial applications of the technology.
But Hague’s 100 person strong group, which
since Dec 2018 has been based in a sparkling
new facility within the university’s £24 million
Advanced Manufacturing Building, is now
pushing the envelope even further by exploring
and developing the materials and processes that
could ultimately enable engineers to print
functional components in one shot, unlocking
the potential of the technology across an
ever-widening range of application areas.
“We’re pretty good at the design side of
things, we can create all of these fantastic
structures and do topology optimisation,” he
told The Engineer. “But the key thing is the
material. The major expression of design
freedom is in added functionality, so in many
respects we’ve become a functional-materials
for additive group.”
Hague’s lab boasts a broad and eclectic mix
of technologies aimed at addressing this: a
blend of systems - unlikely to be found
anywhere else in the world - that ranges from
nanoscale lithography devices and exotic
purpose built research machines able to jet
liquid metal, through to the chemical and
analytical facilities required to develop and test
promising new materials.
But during a recent visit to the centre, our
first port of call was in more familiar territory, a
collection of single metal laser sintering
Jon EXCELL reports
machines of the kind found throughout
industry.
These systems are being used to test and
explore a new generation of metallic materials
optimised for AM. “In the metal powder bed
processes most of the commercial materials
available have been designed for other
processes,” explained Hague, “for example, the
aluminum silicon materials are casting
materials and Ti64 is a wrought material. They
haven’t been tailored for additive.”
Because of this, he said, these materials
have shortcomings when used for additive
processes. “The SLM process is effectively
micro casting, you’re melting and solidifying,
but the time scales involved are much shorter,
so you get different microstructures that come
out of the processing and therefore different
mechanical properties. Normally the tensile
and compressive strength are comparable but
April 2020 / www.theengineer.co.uk 24
engineers to 3D print highly efficient electric
motors, said Hague.
The group’s addressing a related challenge
for single material polymer sintering systems
where, said Hague, the development of
materials with the right properties is even more
challenging. “It’s much more difficult to get
polymers in a powder form,” he said. “Broadly
you melt metals, spray them, and they turn into
little droplets, then you can sieve them and
create powders. You can’t do that with polymers.
You need to find different methods of creating
the particles at the polymerisation stage – and
that is challenging.”
Whilst research in these areas will ultimately
help improve the utility of existing processes,
the centre’s most groundbreaking and exciting
work is arguably in the field of multiple and
functional materials.
Much of its research here is based around the
use of modified ink-jetting technologies, where
systems equipped with multiple jetting heads
are used to simultaneously deposit different
materials onto a build platform.
A key area of interest is using this technology
to jet so-called loaded materials. One example
shown to The Engineer was a jetted silicon
material containing nanoscale semiconductors
that fluoresce when stimulated by light. Such
the team is exploring the
area of metal-jetting, which
is something of a holy grail
for additive researchers
around the world
typically you get worse fatigue.”
Alongside trials of proprietary versions of
existing materials, this area of the lab is also
exploring the use of more exotic materials. One
project, for instance, is looking at the challenges
of additively manufacturing permanent and
non-permanent magnetic materials. The ability
to topologically optimise such materials and
tailor the magnetic field could ultimately enable
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