My friend Eddie has a small coffee grinder that has given him many years of faithful service but a broken part has rendered it less useful than it could be. I’m not sure what the official term is, but I’ll call it the sweeper. It’s the part that sweeps the ground coffee out to the exit chute as it is ground. I thought I’d try to 3D print a replacement part.
3D Printing precision parts can be tricky as there are limitations when you are depositing layers of molten plastic on top of one another to make a part. Luckily, the most precise bit of this part is the brass hex bush, which I could re-use. I used the basic measurements of the broken sweeper to create a quick model in Google SketchUp. You can use any of the more complex (and expensive) design packages, but for 99% of the work I do, SketchUp works just fine (and it’s free).
Here’s the printed part, fresh off the Makerbot 3D Printer. It needs a few stray bits of filament trimmed, but otherwise ready to go.
Tidied up, with a quick sand and trim (you wouldn’t want any bits falling off into the coffee). The brass bush will just friction fit into the new sweeper.
And here’s the new sweeper installed and tested with some coffee grounds. The tolerance is pretty tight so as not to leave any coffee behind. I used ABS plastic for this print as it’s the most food-safe feedstock I have. It melts at 220 degrees Celsius so even if any bits do get into the coffee grounds, the extraction water wouldn’t be hot enough to melt it into the finished coffee.
And that’s it. One less appliance heading to the landfill for want of a single broken part. Best of all, now the part exists digitally, anyone who needs a spare can print their own. I’ll upload the part to Thingiverse on the off-chance someone else in the world needs one.