PLA Bioplastic comes as a long string of filament in a spool. It is fed into a 3D printer and melted/extruded like a computer controlled hot glue gun.
Layer-after-layer, the 3D printed object is built much like a log cabin.
Here is a great write-up on PLA material at Creative Mechanisms...
Polylactic Acid (PLA) is different than most thermoplastic polymers in that it is derived from renewable resources like corn starch or sugar cane. Most plastics, by contrast, are derived from the distillation and polymerization of nonrenewable petroleum reserves. Plastics that are derived from biomass (e.g. PLA) are known as “bioplastics.”
PLA material is carbon neutral, BPA free, made from a renewable resource, compostable, biodegradable, does not emit toxic fumes, and does not leech chemicals.
But it is still plastic, and upon first use you would get that plastic taste. It gets better over time as the smoke resin covers the interior walls, but we decided to do something about it.
Each pipe is treated with the smoke of Cherry Captain Black Pipe Tobacco upon bagging to lock in that tobacco taste and afford you a better first hit.