bioplasticsMAGAZINE_1406

3D printing
Low cost
extruder
Specifications of the low cost extruder
Plastics (tested)
Production rate
Motor
Heating
Total performance
Producing affordable
bio filaments
for 3D printing
PLA, ABS
0.5 kg / h
60 rpm, 14 Nm
Up to 300 °C, 48 V, 230 W
0.2 kWh
In recent years the use of low cost 3D printing has become a
significant factor. A student project at the Institute of Plastics
Processing (IKV) in Industry and the Skilled Crafts at
RWTH Aachen University deals with the design and the engineering
of an extruder that produces 3D printer compatible
filaments. Central aspects are low costs and the use of easily
available components. The result is an extruder which manages
the challenge of uniting functional performance and the
minimization of costs. It has the ability to produce customized
plastics filaments in a fast and easy way.
The personal low cost 3D printer market grew between
2008 and 2011 at an average of 346 % per year. [1] In the
context of Fused Deposition Modelling (FDM), there are
different requirements that need to be fulfilled by the extruded
filament. The filament should be highly customizable and
available at comparatively low volumes and low cost. To meet
the requirements of small businesses and individuals, a small
and very cheap extruder is needed, which is able to produce
filament with appropriate technology.
The engineering of a low cost extruder
The popular, low cost versions of 3D printers are designed
to be working with thermoplastics (usually PLA or ABS) in
filament shape. These filaments are, compared to pellet
costs, relatively high priced. Especially in the case of using
multiple colours or material properties the user needs to
purchase larger amounts of filament. From this situation,
the idea to produce cheap filament from pellets emerged.
Colours should be individually mixable and produced in small
quantities.
From the beginning, the project was sponsored by the IKV.
Beside the financial grant and the provision of laboratory
extruders, premises as well as professional skill led to the
successful preparation of the theoretical foundations for
single-screw extruders. Hereby, the scientific approach
for designing and engineering the low cost extruder was
ensured. Since the goal was a low cost implementation,
the core components of an extruder should be replaced by
simple, products commercially available in any hardware- or
DIY-store.
Components of the low cost extruder
From a cost-perspective point of view it is obvious that one
cannot fall back to complicated screw geometries like threezone
screws used in conventional extruders. Therefore a
screw with a simple geometry has to be used. In this case
24 bioplastics MAGAZINE [06/14] Vol. 9