A 16-year-old swimmer who suffered a stroke and partial
paralysis is now recovering thanks to an orthotic
fin prototyped and 3D printed by two product design
Master’s students at Barcelona’s Polytechnic University of
The fin, 3D printed on a dual-extrusion BCN3D
Sigma R17 3D printer, has helped the swimmer, named Pedro,
to improve his body positioning in the water, swim for longer
without fatigue, and allowing him to build upper body muscle.
Swimming to recovery
Pedro suffered a ganglion basal hemorrhage in 2012,
causing the right side of his body to become paralyzed. While
he gradually recovered thanks to physiotherapy, the
muscles in his right hand remained permanently contracted due
to post-stroke spasticity, which affected his movement in the
This led his swimming club to contact the UPC’s CIM center for a
customized solution to help his right hand. The
students, Marc Roca and Iñigo Martínez-Ayo, took on the
project to design and manufacture a device within a short time,
so as to allow Pedro to continue swimming.
Pedro about to take a
dive with the 3D printed fin. Photo via BCN3D.
Ten prototypes for under €100
Having settled on an orthotic fin, Roca and Martínez-Ayo
set about prototyping the product to ensure maximum
efficiency and a comfortable fit, using a BCN3D
Sigma R 17 3D printer.
By 3D printing the test designs, the designers were able to 3D
print ten functional prototypes with different shapes and
materials within their materials budget of €100.
Combining Nylon and PVA
The designers settled on manufacturing the fin using Nylon due
to its relative durability, flexibility, and resistance to
corrosion, especially when exposed to chlorinated water.
Thanks to the dual extrusion capability of
the BCN3D Sigma R 17, the designers were
able to 3D print the fin in Nylon whilst simultaneously
printing supports out of water-soluble PVA material. This
facilitated the printing of complex shapes and geometries
without the need for extensive post-processing.
The entire product was developed within four weeks, allowing
Pedro to return to the pool with only a short period away, an
especially important consideration
when designing for sports injuries.
Pedro swimming after wearing
the 3D printed fin. Photo via BCN3D.
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Featured image shows the 3D printed orthotic fin on Pedro’s
spasticity-affected hand. Photo via BCN3D.