Multi-material DLP printing: Enhanced layer stacking precision with common flexible interface support

Abstract

Multi-material photocuring technology is an effective approach for fabricating multifunctional integrated devices, widely utilized in fields such as mechatronics, biomedical engineering, and aerospace. However, current multi-material additive manufacturing technologies exhibit low positional accuracy in thin layers, which is sensitive to build size and may lead to inconsistencies in material layers. Additionally, the material exchange process often introduces air bubbles into the cured layers, adversely affecting mechanical properties and potentially causing structural failures. This study presents a novel digital light processing technique based on multi-resin reservoirs with a flexible release interface supported by a common datum, investigating the impact of common platform support on layer stacking accuracy within multi-material systems. Furthermore, the research reveals the mechanisms by which bubbles are entrapped during the immersion of multi-material printed devices into the resin reservoir and proposes the Two-Sides Cooperate to Enter the Reservoir (TSCETR) method to mitigate bubble residues within the cured layer space. Ultimately, multi-material microfluidic devices featuring complex flow channels are fabricated, demonstrating high precision in channel characteristics. This innovative multi-material printing system enhances the stacking accuracy of multi-material layers and effectively reduces bubble defects in printed devices, offering a promising pathway for advancing the surface customization of microfluidic devices.