Plastics News Europe - September 2019 - 10

injection moulding

From plastic to metal
in injection moulding
Injection moulding is a highly effective
process for producing large quantities
of plastic components. Heraeus and
Engel have now successfully transferred
this process to amorphous metals and
are one step closer to meeting a wide
range of challenges that companies in
various industries are facing

rom automotive applications and
household appliances to packaging, medical devices and much
more, injection moulding has become
an indispensable part of production in a
wide diversity of industries. For certain
plastics, injection moulding is the process most frequently used for manufacturing high-quality and durable products. The advantages of this process are
clear: from raw material to finished
functionalised plastic part, injection
moulding offers a seamless one-step
production process that is both efficient and provides advantages for the
manufacture of precision parts.
"In particular, extremely small individual parts benefit from precise
production," says Valeska Melde,
Sales & Marketing Manager at Heraeus Amloy, a new business unit
founded by Heraeus in 2017. "Usually no further post-processing is
necessary, so that production can be
completed quickly."
Once an injection moulding tool
has been manufactured, it can be
used again and again, plus the
moulding process itself is fully automated. Moreover, after all the components have been installed, permanent monitoring is unnecessary.
In cooperation with machine manufacturer Engel, Heraeus Amloy is
now applying the advantages of injection moulding to a completely new
material: amorphous metals. What
makes these metals so unique? They
combine properties that previously
were mutually exclusive, offering
both high hardness and strength as
well as high ductility. Modern hightech applications place enormous demands on today's materials, whether
they are wear-resistant gears and
drive components, stable suspensions
or diaphragms for injection nozzles.
"Complex designs and significant
reduction in weight can no longer be

Frames for mobile devices made of amorphous metals are scratch
and impact resistant. The exposed areas are injection moulded from
amorphous metal and will be encapsulated with plastic for sealing

achieved with conventional materials," says Valeska Melde. Amorphous
metals offer a solution. Their secret
lies in their disordered internal structure. Basically, they are frozen metallic liquids and are also called metallic
glasses. "In order to produce amorphous metal products, extremely high
cooling rates of 1,000,000 Kelvin per
second are no longer required to
shock-freeze the melt. Thanks to material optimisation, we can get by
with cooling rates of around 100 Kelvin per second," says Valeska Melde.
As a result, the individual atoms do
not have the opportunity to form an
ordered metal lattice, as is typical for
a crystalline state.

Atomic chaos is the
solution
Although metallic glasses are chaotic,
they are by no means fragile - in fact,
quite the opposite. Thanks to their
unusual structure, they possess a
unique profile of properties. Amorphous metals are extremely stable
and resistant to corrosion and wear,
yet are also highly elastic. They are
also excellent at storing and releasing
mechanical energy.
"You might say they are the 'rubber' among metals. At the same time,
they are practically indestructible,"
says Valeska Melde. With their glasslike structure, these metal liquids can
even be thermoplastically deformed,
just like plastics - but thanks to their
other properties, amorphous metals
are superior to plastics in many areas
of application.
Hanau-based technology group

Heraeus founded the Amloy (Amorphous Alloy Technologies) business
unit two years ago to manufacture
finished products and components
such as scalpels or pliers on an assembly line. Its main focus is on the research and development of amorphous metal alloys - the company
specialises in the manufacture and
processing of these remarkable materials. Heraeus Amloy is the only supplier worldwide that can also process
these using different processing technologies. In addition to injection
moulding, the company also melts
and shapes amorphous alloys, and
uses them in additive manufacturing.
"Our latest development is based
on an amorphous alloy of zirconium
or copper," says Valeska Melde. "We
manufacture this material ready for
use and optimised for injection
moulding." As injection mouldable
materials, metallic glasses open up
new avenues for mass production -
and for use in a wide range of industrial applications.

Superior process for
modern applications
A few years ago, metal injection
moulding (MIM) was still the most
promising near-net-shape manufacturing process for metal components.
The process was then optimised, and
costs reduced for a range of specific
applications. At the same time, however, the limitations of this process
became increasingly apparent. MIM
requires a number of process steps
and often rework, as tolerance compliance can be an issue. During the

september 2019

Plastics News Europe - September 2019

Table of Contents for the Digital Edition of Plastics News Europe - September 2019