Many are saying that additive manufacturing is the key issue for production
engineering in the future. Conventional manufacturing technologies are being
supplemented to an ever increasing extent by three-dimensional printing, which
is already in successful operation in many sophisticated fields like the medical
engineering, automotive and aerospace industries. The foundry, steel and
aluminium industries have also recognised the potential of 3D printing.
A look under the bonnet of the demonstration
vehicle shows the potential that industrial
3D printing has for the automotive industry:
few components but with more functions
and considerably less weight.
The new crash-proof front end structure of the old
VW Caddy, which weighs 34kg, is made from the
extremely strong and tough high-performance alloy
Scalmalloy from the Airbus subsidiary APWorks
using a 3D printer supplied by the German
company EOS. The 3iprint project that was carried
out under the leadership of the development
service provider csi won the “German Innovation
Award 2018” in mid-June. The aim of the Caddy
concept is to indicate what is technologically
possible in automotive production using new
design methods and new materials with the help
of additive manufacturing.
Three-dimensional manufacturing processes,
which is the general term used for the various
additive production technologies with all the
different kinds of 3D printing systems, are
where the future lies. Additive manufacturing
with plastics, metals and ceramics is already an
essential feature of industrial production today.
Almost 40% of the German companies surveyed
in 2016 already used 3D printing, as the consulting
firm EY determined. The potential in all the different
fields is tremendous. 3D printing with concrete
could revolutionise the construction industry, while
the bioprinting of living tissue is already possible –
and even the printing of human organs is an issue
that is the subject of serious research.
3D printing is creating new opportunities for the
metal industries from aluminium and steel to
titanium and special materials – whether foundries
and steel mills or forging and sheet processing
companies are involved. With 3D printers,
structures are produced layer by layer on the
basis of digital design data. Material is only used
where it is needed. Additive technologies have
their strengths where conventional manufacturing
processes like casting, milling or forging reach
their limits. 3D printing gives designers unlimited
geometric freedom. Complex components with
a bionic structure and integrated functions can,
for example, be produced with varying wall
thicknesses, cavities and honeycomb structures –
like the heavy-duty, lightweight metal, automotive
structure from the 3iprint project.
The production of small batches and even of
individual components is economically viable with
3D printing too. Die casting moulds or forming
tools are not needed, which can quickly lead to
tool cost savings of several tens of thousands
of euros. Individualised components, prototypes
and spare parts that are rarely needed are
therefore considered to be the domains of additive
manufacturing. 3D printing is not, however, the
universal “assault weapon” for attacking the
bastions of established production engineering.
The manufacturing expert Franz-Josef Wöstmann
from the Fraunhofer Institute IFAM in Bremen says:
“Additive manufacturing is a supplement not a
substitute.”
3D printing reaches its limits at the latest
where large product quantities can be made
economically with conventional manufacturing
processes. This is primarily the case in the
high-volume segment of the automotive industry.
Additive manufacturing with metal is not
productive enough for mass production in series
at the present time. Dr Stefan Geisler, innovation
manager at KSM Casting Group in Hildesheim,
is certain: “3D printing will be increasing for
premium vehicles and for a limited number of
components, but it will not succeed in replacing
foundries.” He is convinced that the quantities
needed in the volume market cannot be reached
even with the faster layering speeds possible, for
example, using additive manufacturing with wire.
Geisler points out: “What is often forgotten is that
additive manufacturing cannot overcome the laws
of physics either. In the final analysis, all that are
involved there too are processes: melting and
cooling. There are limits to the speed at which this
is possible.” In addition to this, the printed articles
need to be machined into finished functional
components.
Another definite disadvantage of additive
manufacturing with metal is the high energy
consumption involved. Dr Wolfram Volk, Professor
of Metal Forming and Casting at Munich Technical
University, calculates that about twice as much
energy as in conventional casting is required for
the laser melting of metal, from powder production
to the finished component.
Additive processes are becoming an increasingly
common element of existing process chains.
How additive manufacturing and machining
can be combined to carry out comprehensive,
hybrid processing in a single machining centre
is demonstrated by, for example, the machine
tool manufacturers DMG Mori and Hermle. A
market leader, DMG Mori supplements laser
metal deposition by subsequent machining in the
form of turning and milling. Its competitor Hermle
extends a multiaxis machining centre by a thermal
spraying process using its MPA (metal powder
application) technology, in which metal powder
NOT ONLY HEAT MANAGEMENT BUT ALSO PASSIVE SAFETY,
LIQUID STORAGE AND OTHER FUNCTIONS WERE INTEGRATED IN
THE ORGANIC, LOAD-DRIVEN DESIGN OF THE FRONT MODULE.
PHOTO: CSI
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