Cafelat Robot Magnetic Arm Latch

While using the Cafelat Robot there are times when you'd like the arms to stay in the up position without needing to use a hand. This design does this while staying relatively unobtrusive and small.

These were printed in PETG as a bit of flexibility is needed when pushing the print over the Robot arms. I've printed with a layer height of 0.12 and 0.20. Both work. I used a higher than needed infill using the Gyroid pattern as I think it works well with PETG. The hardware is M3-20 mm bolts, nuts and washers. The left magnet is 3/16" diameter x 3/8" long and the right is 3/16" diameter x ¼" long. Both are Rare Earth Neodymium N42, but I think even stronger ones are available in those sizes. I've found that the magnets could be pushed into the print and stay in place. Because of the difficulty of gluing to PETG, I've included a small glue pocket which could be filled with an epoxy that bonds to the magnet and once set forms an anchor for the magnet.  In the up position the Robot arms meet at about a 85° angle so the mating surface of the right piece is canted back by 5° so the two parts meet flush.