Star Wars fans will appreciate this fun one piece moving print of a BB8 style droid. It prints flat... so not a ball but (on an accurate well set up 3D printer) the centre section rotates freely from the outside / head.
This is small and easy print but does require you to pause your machine twice during your print to change the filament colour. With a 1mm thick Raft, change the filament color at 2mm (29%) and 7mm (86%) through the print. Following this simple process should provide a great fun print.... the color change point is critical to the result. May the force be with you!
Two options have been provided. One is a 'Just fro Fun' print as a fun example of how moving / linked parts can be built in a single print. The Key Fob version has a slightly different top with a hole for a key ring. At standard scale the total diameter of the design is 35mm. Scale it up uniformly if you want to make it slightly bigger (if you have clearance / sticking issues stopping it from freeing up to rotate) but not down as that will reduce the fine clearances.
Due to the fine clearances used in this design the rotating centre may need to be gently broken away to make it spin freely.Printed on an accurate 3D printer this should be relatively easy to achieve by running a finger nail around the grooves (Refer to the images).
Please refer to the images and instructions for additional information.
Two Colour Files: At the request of several Thingiverse members two files have been added for multi-colour machine users. Part "A" is for the bottom and top sections (White). Part B is for the centre section (Orange). There is a version for a key fob and one just for the BB8 model.
Note: If you like this check out the rest of my fun and practical designs... and post images of your prints!
Raft is recommended (This thickness needs to be factored in for colour changes... allow 1mm).
Do not use any support as that could stop the ability for the centre section to rotate.
Change colors at 2mm (29%) and 7mm (86%) through the print with a 1mm Raft. Easy to do...
Print with 2 shells and high infill (75% recommended). This will ensure it is strong enough to be used as a key fob.
Remove Raft and free the centre section
Break / cut away the Raft then free the centre section until it rotates freely. If your print won't free up is may be because your machine cannot handle the fine clearances. If this is the case try uniformly increasing the scale by 5%. This will increase the clearances.