ADDITIVE MANUFACTURING PLASTIC & METAL PROCESSES IN A SINGLE MACHINE
scaling the object before it is printed.
According to the company, prototypes
have been well received, particularly from
the automotive industry where glass-fibre
filled plastics are commonly used. Margins
there are low and there is a constant need
to adapt, so with a 3D printer that no
longer relies on its own ecosystem but
works with readily available, standardised
materials and tools, the potential exists to
significantly reduce the costs of AM,
AIM3D underlines.
Most recently, the company has
suggested spares for discontinued parts
HepcoMotion’s slimline
bearings and the NV20 slide
from its GV3 linear guide
system provided
the best
solution for
AIM3D’s
needs
as an
area where
its machine and
process can offer a solution. Exampling a
component of a box lock, a spare part
required in large quantities in, for example,
regional buses. The original lock latch was
a zinc die casting. Using the ExAM 255, a
spare part made of steel boasts a longer
service life. Indeed, many previously diecast
industrial parts can already be printed
cost-effectively in the company’s
equipment. ■ (AM news update, p16)
Perfect alignment, not so easy –
the UK’s HepcoMotion helps out
The ExAm 255 uses two print heads in
order to easily deal with possible material
changes. During the printing process, the
second print head that is not being used,
is constantly being lifted by 10 mm, so it
does not collide with the object to be
printed.
“To make the printing process as
accurate as possible, it is crucial that the
two print heads are perfectly aligned, even
at fast speeds. In order to avoid shock
during printing, the support of the print
bed must also be constructed so that it is
completely stable”, explains Rene Zielke,
head of plant development.
“In addition, since the mechanism for
raising and lowering the print heads is
such a visible interface between the user
and machine, it was important to us that
the linear guide looked and felt highquality,”
she adds.
While the AIM3D engineers aimed at
drastically reducing the cost of additive
manufacturing, they did not want to do so
by compromising on quality. However,
finding this combination of features at an
acceptable price proved more challenging
than expected. The HepcoMotion (https://
is.gd/wozuyu) solution showed itself
superior, with slimline bearings and the
NV20 slide from its GV3 linear guide
system the best answer.
The bearings are directly mounted to
the two changeable printer heads and,
along with HepcoMotion’s NV20 slides,
they ensure that the printer head is moved
up and down at a speed of 2.5 m/s with
absolute precision. The required X-Y
movement is achieved by three ballscrews;
two on the X-axis and one on the Y-axis.
Z-axis movement for the print itself is
achieved via two ballscrews.
CEM E-1 Extruder
print heads. The
printer can process
almost any injectionmoulded
granulate up to a
diameter of 3 mm. Explains Radon:
“The really special thing about the
E-1 Extruder is that the customer
does not have to purchase expensive
polymer filaments or metal powders.
The same material can be used for
prototypes and final manufacture, making
the transition from prototype to finished
product more economical and faster for the
end user.
“In my opinion, we are the only company
so far to have developed such a universally
employable 3D printer. Although there are a
few that work with polymer granules, they
do not offer choice in the range of materials
and this is a unique feature of our system,”
explains Rene Zielke, who is head of plant
development.
The system sees inexpensive metal
injection moulding granulate turned into fine
filament applied in layers. The ExAM system
does not need to be tuned to a new metal,
but usually only to the matrix material – the
plastic carrier. This matrix material is
usually very similar for most metal injection
moulding pellets, thus enabling fast and
cost-efficient material adjustments.
Only the plastic component of the metal
injection moulding pellets is melted during
the printing process. The metal powder,
which is bound by the plastic, thus forms a
green compact, which is still relatively
fragile. Following this, the component may
be reworked before the actual sintering
process, which in turn reduces tooling and
machining costs during post-processing.
During a following sintering process, the
plastic component is then dissolved
chemically and thermally, and the
temperature in the oven is increased
almost to the melting point of the metal.
This leads to a connection of the metal
particles at a molecular level, which
ultimately results in a stable metal part.
The resulting sintered part is slightly
smaller than the printed part, as it shrinks
during the sintering step. This shrinkage is
mostly homogeneous in every direction and
independent of the material used, meaning
that it can be easily considered by simply
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