Nylon Monofilament by Melt Spinning

Fishing line and strimmer line are single strands of nylon. Molten nylon is extruded through tiny holes, a spinneret, into strands, which are cooled, stretched to line up the polymer chains and give strength, and wound on spools. Hole size and stretching set the line's thickness and breaking strength. It is the 3D-printer filament line made much finer, and drawn.