The compatibility of computer-aided design (CAD) with computational fluid dynamics (CFD) softwares was used to establish a digital and lean development method for 3D-printed reactors which allows for shorter development cycles and targeted process setup. CAD modeling, as the starting point of an additive manufacturing process, creates 3D-designs, which can be directly evaluated by CFD simulation. Thus, challenging assumptions or issues regarding the performance of a tubular reactor can be visualized and redefined to create iteratively new strategies and solutions in a cost- and time-effective way. Our approach enables to build and deliver reactor designs incrementally and faster as it can be performed digitally and tailored to specific requirements. The developed reactor design subsequently can be fabricated directly by 3D printing techniques. The method is based on an established 3D-printed tubular bended reactor for emulsion polymerizations, without being limited to a specific case and enabled the lean fabrication of a tubular reactor being developed to proactively use Dean vortices by reducing dead zones in a more compact design. Optimized flow patterns were further obtained by the tailor-made implementation of static mixing elements at targeted positions of the reactor design. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.