NEW PLASTIFICATION CONCEPTS FOR MICRO INJECTION MOULDING

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.