OpenSCAD Rubbermaid 21-cup container rim profile

thingiverse

This is an OpenSCAD module that generates a rim profile shape of a Rubbermaid 21-cup translucent food container, commonly used for filament dryboxes. I needed a parametric model I could work with, not an STL or a parameter-less STEP file as provided in other Things here. For example, https://www.thingiverse.com/thing:3138757 and https://www.thingiverse.com/thing:3245554 don't cut it for me. The rim is composed of three distinct arcs: a small-radius arc for the corners, a medium-radius arc for the short sides, and a large-radius arc for the long sides. Combining different-sized arcs means that nothing meets at neat 90-degree angles, so I had to optimize the arc start and stop angles and center positions to fit within the constraints of the container rim. This profile generates an entire surface with the lid profile in place. Use the 'offset' parameter to generate a surface larger or smaller, and use the OpenSCAD 'difference' function to cut the rim out from a larger profile to make a lid that wraps around the container's rim. The lid will be tight with no clearance, so I suggest your cutout is 0.1-0.2mm larger than default. An example of how this works is given in the OpenSCAD file. This object measures about 240mm long. A Prusa i3 printer has a build surface large enough to print this.