Below is a collection of 3D printing models I've developed for various research projects. All of these were designed using OpenSCAD and have been printed (in PLA) and verified using a Makerbot Replicator 1.
This insert fits tightly into disposable Eppendorf cuvettes (Uvette). It was designed with the intention of removing the headspace above an oxygen sensitive sample without having to purchases expensive quartz cuvettes with PTFE stoppers.
This is a customizable rack originally designed for holding capillary electrophoresis vials. The scad file allows you to change the array size, as well as the diameter of the vial slots.