Preliminary study on the manufacturing feasibility of microfeatures for microfluidics by DLP stereolithography

Lab on Chips (LOCs) are devices mostly based on microfluidics (i.e. structures for liquid handling with cross sections of 1 - 500 ?m and femtoliter to nanoliter volume capacity), which allow to perform one or several chemical, biochemical or biological analysis in a miniaturized format on a single chip. The emerging Additive Manufacturing (AM) processes could produce a complete LOC with microscale complex 3D shapes in a single step without the need for assembly processes. Stereolithography, especially when exploiting the Digital Light Processing (DLP) technology, is the most promising AM process for this purpose. In this study, a suitable benchmark part was designed to assess the feasibility of manufacturing microfeatures by DLP-SLA and to evaluate the performance of the employed system in terms of the minimum feature size, dimensional accuracy and spatial repeatability. A proper experimental campaign was specifically studied to point out the effect of the main process parameters (namely, layer thickness and exposure time) and the feature position within the building platform on the process performance. The results demonstrated the manufacturing feasibility of the selected microfeatures. Moreover, they showed that both the process parameters influence the minimum feasibile feature size and that the dimensional accuracy changes with the feature position.