Process:
The tube is fed longitudinally through the rear of the machine while the aluminum fin strip, which is usually located below the bare tube rack, is tension wound around the circumference of the tube perpendicularly.  The fin strip is carefully guided to the primary forming roller and spindle roller by adjusting the angle and rolling force of the primary forming roller, the external fibers of the fin are rolled with a uniform taper.  The fin curls as a result and hugs onto the circumference of the tube, and hence forming a spiral finned tube.