Micro-stereolithography tools for small-batch manufacture of polymer micro-parts

Abstract

Rapid tooling solutions can be used to manufacture prototypes and small batches of parts that are critical to part and tool design verification and thus to minimize the production cost and lead time in developing new products. Layer-based manufacture of prototypes is a proven technology for an early assessment of the designs of products and, with the introduction to the market of new micro-stereography technologies, rapid tooling becomes an important option for low-volume production of polymer micro-components. Thus, to broaden the use of these technologies, it is necessary to understand the behaviour of rapid tooling inserts under cyclic thermodynamic loads. The paper investigates a rapid tooling solution for fabricating ‘soft’ inserts that are validated by injection moulding small batches of polymer parts. The mouldings produced using such soft tools are analysed and conclusions are made about the tool-making capability of the micro-stereography process. In particular, it was found that the soft inserts were fabricated with sufficient accuracy by employing this rapid tooling process. Also, it was experimentally validated that they could be applied successfully to produce small batches of functional parts, and in particular to a lens micro-device. The most important factors affecting their injection-moulding capabilities were the build orientation of the inserts and the process settings to account for the build-up of thermal energy during the replication cycles.