SHOW PREVIEW
ARBURG OPENS UP
INDUSTRIAL ADDITIVE MANUFACTURING
SEE THE FREEFORMER AT EMEX 2018 – GET UP CLOSE AND PERSONAL – WHILE
IT'S IN OPERATION.
The Arburg freeformer open additive manufacturing
system, distributed in New Zealand by Aotea,
is what your business needs to produce high-quality
additive manufacturing functional plastic parts;
ideal for one-off parts or small-volume batches.
With the system users can transform 3D CAD data
quickly and simply – without a mould – providing
greater freedoms in the selection, combinations
and processing of plastics.
A technician from Arburg will be at EMEX to talk
you through the technical side of the machine and
what you as an end-user can achieve with it.
Open freeformer manufacturing system
The industrial additive manufacture of functional
parts is highly demanding. The freeformer and the
Arburg Plastic Freeforming (APF) were developed
as an open system which affords users independence:
Customers can qualify their own original
material and optimise the freely programmable
process parameters specifically to the relevant
application – starting from the settings for the
geometrical slicing and temperature, through to
discharge.
But what does this mean? The APF process
uses qualified standard granulates, which are
also used for conventional in-jection moulding,
can be processed. For this, the freeformer is
equipped with a material processing unit featuring
a special plasticising screw. Plasticising is followed
by freeforming without the use of a mould. A
nozzle closure actuated via high-frequency piezo
technology discharges tiny plastic droplets, which
are applied in a very precise and flexible manner
by means of a moving part carrier. This enables
the desired three-dimensional plastic parts to be
built up layer-by-layer.
Droplets render part construction flexible
Individual setting options comparable to those for
injection moulding are made possible, provided
droplet size and process control can be influenced
in a targeted manner.
For this purpose, various nozzle sizes with
diameters from 0.15, 0.2 and 0.25 millimetres
are available. The discharged droplets, however,
are not round and their shape is significantly
influenced by the viscosity of the material. This
needs to be taken into account during layer
build-up. The droplet height determines the layer
thickness. This varies between 0.14 and 0.34
millimetres. The so-called form factor is also
used to determine the volume of a droplet. This
describes the width to height ratio of the not-precisely
round droplets. The layer thickness and
form factor therefore also depend on one another.
This is taken into account by mathematical
algorithms during slicing and consequently during
creation of the machine-specific NC program.
Doubling of the form factor, for example, results
in an allowance of four times more space for a
droplet.
It’s now possible to create different structural
properties in a targeted manner. The more
densely the droplets are positioned in relation to
one another – or the more tightly the parts are
‘packed’ - the higher the mechanical properties
are. Today, depending on the material, part
densities of up to 95% can be achieved compared
to injection moulding, enabling tensile
strengths of up to 97% to be achieved,
for example (tensile test according to
DIN EN ISO 527-02).
With smaller layer thicknesses, finer
surface finishes can be achieved.
Greater layer thicknesses, in turn,
shorten the build times.
Individual part optimisation
In comparison with other standard
processes on the market, with
freeformer it is possible to optimise the
quality and strength of additively manufactured
parts using APF, depending on
the specific material employed.
A prerequisite is an ‘open manufacturing
system’. With the freeformer, all
the process parameters are freely programmable
– from the settings for the
geometrical slicing, positioning of the
droplets and temperature, through to
discharge. This great freedom, however,
requires a structured procedure for
qualifying materials and determining
pre-optimised process settings. The
material database for the APF process
is growing continuously and contains
setting data for a wide variety of thermoplastics.
These include additive standard
materials ABS, PC, PA12 (amorphous),
as well as partially crystalline PP, and
special plastics such as the high-temperature
material PEI, elastic TPU
and biopolymers. Taking these as
the starting point, modified original
materials can also be used quickly and
easily, for example, a PC approved for
the aerospace industry or a resorbable
PLA for the medical technology sector.
36 April 2018