Desktop Millifluidics With SLA 3D Printing

This report delves into the implementation of millifluidic geometries using stereolithography (SLA) 3D printing. SLA printing enables chip geometries not possible with traditional lithographic techniques, which rely on laminated layers of 2D devices. What 3D printed chips bring to the table are improved performance, while reducing the cost of customized design. 

Read on to learn best practices for fabricating millifluidic chips in-house on the Form 3, with example prints and test results. The report will outline best practices, design considerations, and unique applications that SLA technology brings to the world of millifluidics. By the end, users will understand what is possible on a Formlabs printer, and be able to request a free sample part to view a millifluidic chip printed in Clear Resin. 

With its high accuracy and ability to produce watertight parts, SLA 3D printing is on the leading edge of a new way to fabricate miniaturized fluid transport systems, known as millifluidics. Complex chips of networked channels smaller than a millimeter in diameter are designed to efficiently mix fluids, separate suspended materials, and many other functions within experimental scientific equipment. Millifluidic chips have applications in biotechnology, chemical engineering, and pharmaceutical engineering. This also makes them vital for educational institutions training the next generation of scientists and doctors.

Globally, most millifluidic channels are manufactured using lithography masking, where troughs are selectively etched onto glass plates in a 2.5D pattern. Outsourcing the custom fabrication of fluidic designs using this process typically comes at a high cost (bringing a traditional photolithographic technique into your own lab is also costly) that is not always economical or time efficient. Additive manufacturing offers a solution for rapidly producing functional millifluidic chips on demand. Without any additional cost for complexity, a custom chip can be made at the same cost as a generalized one. With the a SLA 3D printer from Formlabs, chips can be manufactured as needed and in only a few hours, removing the need of dealing with bulk purchases and shipping times.

The Formlabs resin library has specific material solutions for many of the fields that implement millifluidics with a selection of biocompatible, temperature resistant, and optically clear resins.

Across all fields that implement millifluidic workflows, there are certain properties of a chip material that are necessary to conduct useful experiments.

Optical clarity enables visual confirmation and assessment of fluid behavior and channel performance. Internally, the material must be optically clear, and the surface should be easily polished. The Form 3 prints translucent parts in Clear Resin, which guarantees visibility into the mixing channels. All parts in this report were printed on the Form 3.