Has anyone tried mixing PLA with 3M microspheres, (other microspheres are available).
Microspheres are sold as a lightweight filler material for use with glassfibre and plastics. They range from about 10 to 100microns in diametre and the smaller sizes can be used in injection molding. They seem to be away of adding both strength and lightness.
It occures to me that microspheres might be added to the molten plastic mix in the extruder head at the time of printing. Thus giving a lighter structure.