This centrifugal compressor was created for use by Dr. Kazuya Tajiri at Michigan Tech for research into rocket engines. The impeller was updated from a model by Christophe Augier on Thingiverse.com. The casing for the compressor was created as a collaberation between David Eychaner and myself. 

The FreeCAD, OpenSCAD and STL files for each of the printed parts are included below. The compressor can be printed in three parts and assembled by placing the impeller on the lower casing and then simply placing the upper casing on the designated rods.  A motor can be inserted through the lower casing to power the impeller. 

The print cost roughly $2.45 overall and can be powered by a small RC motor costing $13.99 at https://www.amazon.com/dp/B0752D1JCC/ref=psdc_2234129011_t3_B076B1GGWJ The compressor can be fully built for $16.44, or less depending on the chosen motor. This is a significant price reduction compared to even the least expensive centrifugal compressors. The most compatible centrifugal blower cost $118.42 at https://www.patrickssupply.com/Fasco-A202-1-Speed-Lennox-Draft-Inducer-Blower-11-p/a202.htm This makes the open source compressor $101.98 less expensive even at the lower end of the market.