W. Michaeli, A.
Spennemann, and R. Gärtner,
Institut
für Kunststoffverarbeitung (IKV), Ponststraße 49,
D-52062
Aachen, Germany
The micro
injection moulding represents a key technology for the economic production of
medium and large series of micro mouldings and the assembly of micro-systems.
Furthermore, plastics materials show a wide range of special characteristics
which offer a great variety of adjustable product properties.
During recent
years fundamental research on the injection moulding of micro parts has been
performed at the Institute of Plastics Processing (IKV) at RWTH Aachen
University /1/. Until this time there have been no suitable injection moulding
machines available for the production of single micro parts, so injection
moulders produce big, but precise sprues to achieve the necessary shot weight
/2/. Very often over 90 % of the plastics materials are wasted.
Considering costs of up to 60 $ for one kg of special material, e.g. for
medical applications, this waste can be an important cost factor. Moreover, the
big sprue increases cooling time and, along with that, cycle time.