Parametric/Customizable Pharmaceutical/Pharmacy Bottle Cap

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See this project's Appropedia page for more information. An example STL is included but you can customize it to your needs. You'll need a bottle that needs a cap and a measurement tool (calipers or ruler/scale). Here's how to use this file: Measure the bottle that needs a cap. The important dimensions are the outer diameter of the opening and the height of the mating area. Download the FreeCAD file and open it. In the design tree, under "Application", double click "Design Spreadsheet" to open the parameters table. Change the parameters to match your cap's needs. Below are descriptions of the parameters as well as recommendations for values. Inner Diameter is the internal diameter of the cap. This should be approximately the outer diameter of the bottle opening plus a mm or two for clearance. Rim Height should be approximately the height of the mating area of the rim minus a bit to allow the tabs to work. Cap Diameter should be a bit less than Inner Diameter to allow a step that prevents the cap from sliding too far down. Cap Extra Height is optional. It adds an extra boss to the top of the cap that can be used for grip or to stack with other caps. If not being used, set it to 0.05mm. Thickness sets the thickness of most cap sections - usually 1.5-2mm is appropriate. Tab Count determines how many tabs there are. The more there are for a fixed tab coverage, the more they can each flex but the more fragile they are. 4-6 or 5-8 is generally appropriate. Tab Thickness determines how thick the base of the locking tab is. It should generally be equal to thickness. Tab Tooth Thickness determines the thickness of the locking tooth itself at the base. It should be set to about half of Tab Thickness, generally. Tab Length determines the length of the tab. Longer tabs flex more and are more fragile but will mate more easily. 3-5mm is generally a good range for 2mm thickness. Tab Total Coverage determines the amount of circumference taken by tabbing. Higher tab coverage will make each tab stronger but will make it harder to mate to the cap. The larger the cap is, the lower this should be. For 25-50mm diameter caps, 40-50 should be appropriate. For 50-100mm diameter caps, consider 20-40. In the design tree, select Cap Body then select File -> Export... in the menu bar. Export the cap as an STL and proceed to slice and print. When printing, there should be no supports needed. Infill can be set low - consider 10-20% with shells set to 2mm to better utilize plastic. Print time varies. With a 0.6mm nozzle and 50mm/s print velocity, I was able to print a ~38mm diameter cap in ~12 minutes. With a 0.4mm nozzle, this would take about 2.25 times as long or ~27 minutes. With double the print velocity, it would take about half as long or ~6 minutes. Account for printing multiple parts to get a fit. Usually one or two prototypes is enough to confirm that dimensions are appropriate.