Rim Assembly, Littmann Cardiology III Stethoscope

thingiverse

This model has not been thoroughly tested or proven to work. It is provided for informational study purposes only. The large membrane holder on a Littmann Cardiology III stethoscope's 44mm OD end can be replicated with this rim assembly. The design can be scaled down to fit the pediatric end of the stethoscope, and it may also suit other models of stethoscopes and membranes. A factory replacement rim assembly is available in a 3M/Littmann parts kit (40003), which includes large and small membranes, large and small rim assemblies, and earpieces. The large rim assemblies are not sold individually. The original rim assembly is made of rubber, making it ideal to use a flexible filament, possibly scaled down so that it stretches over both the membrane and the grooved edge. A second model features a slightly more pronounced lip for flexible materials. Issues arise when printing in PLA: the first model has difficulty seating the membrane firmly against the stethoscope body without rolling or damaging the outer rubber edge of the membrane. The printed rim fits the stethoscope and membrane, but not both simultaneously. Using a different material composition may affect this instrument's function and performance. Additionally, the 3D-printed surfaces are not smooth and would be difficult to keep clean.