A bobble using the head of a model pig - see - http://www.thingiverse.com/thing:23029 - Lucky Pig. It is printed with PLA, a hard, rigid plastic, that makes a sensitive spring. The spring is a 3 dimensional version of Fermat's spiral, see - http://www.thingiverse.com/thing:1771653. OpenSCAD code is included.

MakerBot

MakerBot Replicator (5th Generation)

Yes

Yes

0.3 mm

The spring works well but cannot be constructed without support. To avoid excess support use a high support angle, say 82 or 83 degrees. Needle nose pliers can be used to remove most of the support; follow with tweezers for clean up.

Lucky_pig_head.scad takes lucky_pig_small.stl as input, extracts the head, and outputs lucky_pig_head.stl. Lucky_pig_bobble.scad takes lucky_pig_head.stl as input and outputs the bobble. Substitute an stl file of your choice for lucky_pig_small.stl to create your own head and pass it to lucky_pig_bobble.scad. Instructions are included in the openSCAD code.