Abstract

The fast‐growing 3D printing industry is improving its hardware at an accelerated pace. This includes higher‐resolution printing combined with a wider range of photosensitive resins. The parallel development of rapid tooling (RT) for injection moulding enables upscaling 3D printed designs. Within microfluidics, where prototyping and scalability are key, the development of 3D printed RT for injection moulding could prove a competitive alternative to more traditional tooling methods. In this work, we investigate the dominating parameters impacting 3D printed RT for injection moulding, enabling the delivery of durable, high resolution and optically transparent microfluidics. We found that reducing the sidewall waviness to 1.9 ± 0.4 µm and the interlocking angle to 1.9 ± 0.8°, enhances the mould release success rate to 100 ± 0.0%. We have reduced surface roughness from 1.1 ± 0.1 µm to 0.2 ± 0.0 µm by increasing layer exposure during printing. In turn, this improved the optical transparency of moulded replicas to >228 lp/mm line resolution and increased image contrast and amplitude. Ultimately, the established procedure proved capable of running a small‐scale production (∽500 parts) of a droplet generator with 50 µm channels, with a lead production time of under 3h from CAD to a functional device. This article is protected by copyright. All rights reserved.