Design, Development, Integration, and Characterization of a Control System for Surface Texturing of Parts Printed by an MSLA 3D Printer

Abstract

University of Liège Falculty of Applied Sciences Design, Development, Integration, and Characterization of a Control System for Surface Texturing of Parts Printed by an MSLA 3D Printer Laura TOUSSAINT Supervised by Pr. Jean-Michel REDOUT´ E Academic year 2024-2025 The Microsys laboratory has designed and proposed a proof of concept for a Masked StereoLithography Apparatus (MSLA) 3D printer, able to print layers with a thickness on the order of one micron. This concept could modify surface texturing to achieve rough ness values between 0.5 and 2µm RMS. Thanks to previous research, the z-axis of the printer studied achieves an accuracy of 1.25µm. The goal of this work is to extend this achievement to the x- and y-axes, corresponding to the section of the printed parts. Nowadays, the xy resolution of MSLA printers is influenced by the pixel size of the LCD screen and the uniformity of the light source. The aim is to improve this resolution without changing the traditional LCD screen. The studied printer has pixels of size 31.5µm x 31.5µm. The objective is to divide this resolution at least by 4 and to enable static and dynamic micrometric displacements of the screen. Two methods are proposed and can be combined: the superposition of two different LCD screens and the use of piezoelectric elements to displace these screens. In the first method, the two screens are overlaid, one on top of the other. If their pixels are perfectly aligned, no difference should be noticeable. However, if the screens are slightly shifted so that their pixels are no longer perfectly aligned, the xy resolution will then depend on the relative position of the pixels of both screens. Since adding a second screen requires many mechanical changes, this work focuses on the characterization of possible micrometric movements of only one LCD screen. The process is still designed to enable the future presence of a second screen. This movement is induced by two piezoelectric elements (the second proposed method). Theoretically, the first piezoelectric component can elongate and push the LCD screen from 0 to 25µm along the x-axis. The second one can do the same along the y-axis. This work focuses on the characterization of these piezoelectric elements and the implementation of the software to drive them.