The Accuracy of Micro-molds Produced by a UV Laser Induced Polymerization

This research work deals with the development of a simple and practical method for manufacturing metallic micromachine parts on the order of 0.01–1.0 mm in size. In this method, an ultraviolet laser beam is irradiated onto the surface of a liquid photopolymer material through a mask. The irradiated pattern is then developed to produce a solidified photopolymer mold. Finally, the metallic part is made by an electroforming process. This paper deals with the first process, the making of the photopolymer mold. At first, the accuracy of the mold is estimated by applying the theories of diffraction and absorption of light. Next, the accuracy is examined experimentally. The results show an accuracy of ± 1 μm can be obtained when a proximity transfer of 10 μm between the mask and the photopolymer surface is used. By stacking thin films, thick and high aspect ratio molds with a reasonably high accuracy are made.