3D Printed PCB Microfluidics

Abstract

The combination of printed circuit boards (PCB) and microfluidics has many advantages. The combination of electrodes, sensors and electronics is needed for almost all microfluidic systems. Using PCBs as a substrate, this integration is intrinsic. Additive manufacturing has become a widely used technique in industry, research and by hobbyists. One very promising rapid prototype technique is vat polymerization with an LCD as mask, also known as masked stereolithography (mSLA). These printers are available with resolutions down to 35 µm, and they are affordable. In this paper, a technology is described which creates microfluidics on a PCB substrate using an mSLA printer. All steps of the production process can be carried out with commercially available printers and resins: this includes the structuring of the copper layer of the PCB and the buildup of the channel layer on top of the PCB. Copper trace dimensions down to 100 µm and channel dimensions of 800 µm are feasible. The described technology is a low-cost solution for combining PCBs and microfluidics.

Keywords: 3D printing; PCB; PCB-MEMS; microfluidics; rapid prototyping.

Figure 1

Printer build plate with holder for a PCB; the marked areas are alignment posts.

Figure 2

Technology steps: (a) PCB production—the etch resist is exposed by the 3D printer after the copper layer is etched as usual; (b) printing channel layer—the 3D printing process is carried out on the structured PCB; (c) finalization—unpolymerized resin must be removed from the cavities.

Figure 3

The view in the CAD system and one realized prototype: (a) CAD view of the combined design—the PCB with the copper traces is in the back; the channels and the connectors are opaque gray; (b) photo of one realized prototype—the channel material is opaque for better visibility of the fluid.