The swaging and flat-grinding process to improve the mechanical property. Auger with one spiral wire on the surface is available for Archimedes screw.
Auger
An additional filar twisted on top of a cable tube to create an auger screw-type component.
Swaging
Decreasing O.D. while maintaining inner lumen and stiffness by forging surface, can improve the elongation resistance.
Flat-Grinding
Grinding on the surface in the whole length. It improves the flexibility of the metal tubes without decreasing the inner lumen.
Marking
We can put a mark to make clear the position of the metal tubing.