Adapting FDM 3D-printing for the manufacture of microfluidic devices

Abstract: Microfluidic devices have so far not seen widespread use, even though they could potentially be cheaper, better and faster than traditional methods. A possible reason for this is the lack of a middle step between one-of-a-kind experimental devices and cheap mass produced devices. With ongoing improvements in resolution it is starting to look possible that 3D-printing will fill this role. This thesis sought to investigate what factors limit the currently quite poor effective resolution of fused deposition modelling (FDM), an otherwise very advantageous 3D-printing technique. Specifically it looked at the effect of some of the various settings that govern the printing process, as well as the effect of nozzle diameter. The best effective resolution (here the most the width of a channel could deviate) achieved was 15 µm, close to the optimal resolution of 12.5 µm of the 3D-printer used. The effective resolution did however vary seemingly randomly between 15 µm and 30 µm, with no correlation to any of the properties measured other than possibly the layer height. The data did however show a possible mechanism for a specific defect often seen at corners. It seems a mismatch between movement speed and the amount of material deposited may cause bumps that risk blocking small channels.