Title: Producing parts with multiple layer thicknesses by projection stereolithography

Authors: Pekka Lehtinen; Matti Kaivola; Harri Korhonen; Jukka Seppälä; Jouni Partanen

Addresses: Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076 Aalto, Finland ' Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076 Aalto, Finland ' Department of Biotechnology and Chemical Technology, Aalto University, P.O. Box 16100, FI-00076 Aalto, Finland ' Department of Biotechnology and Chemical Technology, Aalto University, P.O. Box 16100, FI-00076 Aalto, Finland ' Department of Mechanical Engineering, Aalto University, P.O. Box 14100, FI-00076 Aalto, Finland

Abstract: We present a novel method to increase the manufacturing speed and versatility in lithography-based additive manufacturing processes. Usually, a part made with additive manufacturing consists of equally thick layers that are fabricated upon one another. We use a projection stereolithography (PSL) system to manufacture parts containing several layer thicknesses, which reduces the manufacturing time and adds controllability to the system. The method is based on the possibility to control the cure depth by adjusting the operation wavelength. To demonstrate the applicability of the PSL system for this purpose, we used two different operation wavelengths to produce parts that include 50- and 300-µm layers. The method presented in this paper can be used in several PSL techniques to increase their performance by offering a new tool to control the layer thickness without affecting the manufacturing resolution.

Keywords: 3D printing; additive manufacturing; AM; cure depth; layer thickness; multiple layers; penetration depth; photopolymers; projection stereolithography; PSL; SL; SLA; stereolithography.

DOI: 10.1504/IJRAPIDM.2017.087542

International Journal of Rapid Manufacturing, 2017 Vol.6 No.4, pp.235 - 244

Received: 25 May 2016
Accepted: 12 Oct 2016
Published online: 18 Oct 2017 *

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