Tuesday, 27 June 2017

Design tutorial: Modeling a jar lid in Fusion 360

Old tea jar lid
    Remember this thing from last year's '3d Printing around the house'? Well, it's suffered a similar fate to the one it replaced, got dropped and the handle snapped off at a thin point near the base, so I've made a new one with a thicker base as a replacement.

New tea jar lid with old lid handle on lower right
     Size wise, it's about 17 cm across at the rim, so normally I'd have just printed it on my Mini Kossel, but I'm currently in the middle of rebuilding it, so I designed this lid for printing on the Micro Kossel's 10 cm build plate instead. The Fusion 360 source file can be found here, and the STLs are on Thingiverse.

Fusion 360 design file
     After measuring the diameter of the existing lid, both the opening and lip, I sketched up a couple of circles that size in F360, then traced some 10 cm circles to determine the maximum size of an individual section of the lid, this worked out to 6 sections with one small part in the center for the handle. Second step was to draw a cross-section profile and revolve it to create the basic sections, one with a 60 degree angle for the outer sections and a simple full revolve for the handle. Last step of the design process was to add some angled holes for the screws that hold the sections together.

Partially assembled lid with M3x15mm screws
     After the design was finished, it was just the standard slice and print process, it takes about 2 hours for each arc section and about 1.5 hours for the handle section, so about 13.5 hours in total. After printing, final assembly took about 15 minutes to screw everything together.
Finished lid in use