YT user aonemarine made this video review of Machinable wax 3d printing filament made specially for lost wax casting. You print the object you want in wax, make a mold and melt the wax away to poor molten metal in it.
The lost PLA casting method is well known but it needs much higher temperatures to melt the PLA away. Wax is much easier to work with.
There have been some wax-like filaments and resins but there is still no wax filament solution that is well established. Maybe this will be the one.
Here is the video describing the wax:
Here is the video tutorial on how to cast metal with it (wax investment casting):
He uses the wax filament made by http://machinablewax.com/index.php