Patent ID: 8573022

Claim:
A method of manufacturing a tube having a surface, at least two primary grooves located along the surface, and a longitudinal axis, the method comprising: a. using a tool having a tool tip (i) to cut with the tool tip through the surface of the tube located between the at least two primary grooves to a cutting depth, and at an angle relative to the longitudinal axis, to form layers, wherein at least one layer is formed by cutting with the tool tip through the surface of the tube at two different angles relative to the longitudinal axis; and (ii) to lift the layers relative to the surface with the tool tip to form a plurality of protrusions, wherein at least some of the protrusions are adjacent each other, wherein at least one of the plurality of protrusions comprises a protrusion base and a protrusion tip and wherein the protrusion tip is more distal the surface than the protrusion base and thicker than the protrusion base.