Circumbra

grabcad

To commence, the main shape was inspired by the circumcircle. Initially, I overlooked the device's weight; however, I later recognized its significance for both horizontal and vertical placements. Through research, the dry tensile strength of a kitchen paper towel was found to be 650g. Consequently, I designed the main prism part to weigh over 650g to ensure balance during user-initiated tears. For the plastic version, the prism part has a weight of 951g, using PET density for calculations. Additionally, a small FEA analysis was conducted to assess deflection under 7N force (similar to paper tearing). Results confirmed minimal device deformation. Users can customize the prism part's surface and color. Injection molding is suitable for manufacturing all plastic parts, with an option for enamel coating to achieve a metal-like appearance. The sheet metal version features 2mm brushed aluminum, providing a weight of 1.1kg for the prism part - ample for stability. This premium finish makes it ideal for modern household kitchens.