I had several different notions about how to best create pivoting joints.
- Live hinges, flexures made of plastic, would be too inaccurate
- Monolithic creation of all pivots during growth in the SLS machine would be too innacurate
- bearings would be really cool, but too expensive
I finally settled on making the pivots out of stock shoulder screws, and reaming out the parts to a proper fit, and relying on the porous, lubricious nature of the SLS nylon as a bearing surface.
Presently the linkages are a work in progress. Standard R/C equipment will be used wherever possible to keep costs under control, but the eyebrows are proving to be difficult, as they’re in close proximity to the eyelids.
Motors will be R/C servo motors, the kind in small aircraft, boats and cars. The smaller the better, so long as they have the torque.
Presently i am using two types. A vary small one for the eyebrows, eyelids, eye pan and tilt, and slightly larger ones for the face actuation of pan, tilt and roll.