In mid March there was a sudden run on masks and visors, as people sought to minimize the risk of infection by coronavirus. It quickly became hard to find them on the market. Thanks to their technical infrastructure however, institutes and facilities at the University of Stuttgart were able to bypass the shortages and supply local facilities.
The Institute of Polymer Technology (IKT) at the University of Stuttgart soon sprang into action putting its expertise in extrusion and 3D printing to good use by producing visor films, as well as complete face shields. Around 700 meters of film, 300 millimeters wide and 0.6 millimeters thick rolled off the roughly seven meter long production line (“extrusion line”) at the IKT. This was in addition to another 150 meters of film, likewise with a width of 300 millimeters but with a thickness of 0.25 millimeters. One meter of film produced three face shields, meaning that film for roughly 360 film face shields could be produced per hour. Production is still ongoing.
The film used for the visors as well as the filaments required for the process of laying down strips of material (FFF or FDM in short) were produced on the IKT’s extrusion lines and used in the IKT’s 3D printing laboratory. Alexander Geyer, Head of the Processing Technology department at the IKT, said “The IKT stands out from other processors thanks to our expertise with plastics, because we can produce everything ourselves. This means we can modify the materials and customize their properties. We can produce the filaments needed for 3D printing with the exact diameter using whichever material is desired by the specific 3D printer. The transparent film needed for the face shields can be produced in large quantities using our systems technology”. Jens Thurnherr, technical employee and extrusion expert, emphasizes that it has been possible to produce particularly clear films that are tailor made for the visors thanks to the precisely configured extrusion process: “That was the challenge”. The IKT team relied on a bio-based and biodegradable polylactide (PLA) for both the film and the filament.
Visors complete with brackets were supplied to places such as the University Hospital Tübingen, the Marienhospital and the Tafel social services organization in Stuttgart, and others. The biggest purchasers of the film however were the scientists at the ARENA2036 research campus and the neighboring institutes at the University of Stuttgart. They are also using their facilities, which are normally used to produce prototypes for automotive, aircraft or mechanical engineering applications, to produce face shields, and have a high demand for the film produced by IKT.