Determination of Suitable Geometrical Ranges for the Manufacture of Microfluidic Channels by Low-Cost Additive Manufacturing Techniques

Additive manufacturing of microfluidic devices is a field of increasing interest due to the great variety of fields where they can be used, especially in physicochemical, biological and medical ones. These devices include internal channels whose manufacture can be challenging as it takes place close to or into the micro geometric scale. On the other hand, the use of low-cost techniques can provide access to certain services in depopulated areas in different fields, so this approach can be of interest in the development of new products under new production and living contexts. In this work, the geometrical ranges of practical application for the manufacture of microfluidic channels by two of the most common additive manufacturing techniques for polymeric materials (Fused Filament Fabrication and the Stereolithography) are analyzed by means of an evaluation of the dimensional accuracy obtained in samples with channels of circular section. The circular channels present diameters that vary from 2 mm to the minimal size feasible which each printer (a Markforged Onyx One, a Ultimaker S5 and a Formlabs Form3). The Ultimaker S5 (FFF) equipment is the one that presents the best results, being the dimensional deviations around 0.2 mm in a wide range 1 < d nom (mm) < 2; and contrary to the expectations, the SLA system provides the worst results, with a growing trend starting from deviations of 0.6 mm. An obturation effect in the channels has been also detected, being critical in the case of nominal diameters lower than 0.8 mm for the Ultimaker S5 system. In general, it can be concluded that the FFF technology is a more reliable option compared to SLA under the printing parameters considered in this work and for the materials used in this study.