stereolithography

A. Frick (a), C. Stern (a), U. Berger (b)
a Polymer Sciences and Processing, Aalen University of Applied Sciences AAUAS, Aalen 73430, Germany
b Department of Mechatronics, Aalen University of Applied Sciences AAUAS, Aalen 73430, Germany

Abstract

A larger number of polymeric prototypes with special material properties are often demanded for research and development. Thereby, it is most essential that the prototypes are made from the target material and the related processing technique. A sophisticated and fast possibility to obtain a mold for replicating parts (prototypes) by injection molding is making inserts for hybrid molds, using a rapid prototyping (RP) technique. RP technique (e.g. stereolithography) allows shaping complex mold cavity geometries as well as curved cooling conducts, what is not possible by conventional manufacturing.

The manufacturing of high quality micro parts by injection molding requires a plasticizing unit with small screw channel volume to reduce the residence time of the polymeric melt. Nowadays, the minimal commercially available screw diameter is 14 mm. A newly developed plasticizing unit with a screw diameter of 12mm, which was done at AAUAS in collaboration with ARBURG, permits a gentle processing of polymers, spending only half of the residence time. This is an advantage when micro prototypes are manufactured in a single-cavity mold.

The present work points out, how the combination of the benefits of stereolithography and micro injection molding can be successfully used for producing micro prototypes. By means of some examples, it is shown that the performance of small plastic products (part mass in the milligram range) can be optimized by choosing the right material and processing technique. Thus the spectrum of application of micro parts can be extended.