CNC turning and milling

The bottle cap has a cylindrical body with a threaded top. The cylindrical body is most likely made by CNC turning, while the threaded top is most likely made by CNC milling.

CNC turning is a machining process in which a workpiece is rotated on a lathe and a cutting tool is used to remove material from the workpiece to create the desired shape. CNC milling is a machining process in which a cutting tool is moved across the workpiece to remove material and create the desired shape.

Both CNC turning and milling are very precise machining processes, which is why they are often used to manufacture bottle caps. Bottle caps need to have a very precise fit in order to seal the bottle properly.