A New Bending Technique for Very Thin Metal Tubes

A new bending technique was presented for forming very thin metal tubes, which is characterized by ball filler in the tube as force-transferring media during bending process. Due to the good flow capacity and non-uniform pressure, ball filler is considered as an alternative filler to bend very thin tubes. The experiments of ball filler push bending were carried out for very thin copper tubes. The results indicate that the back pressure and lubrication condition have great effects on the forming quality of the tubes. As the back pressure increases and/or lubrication condition improves, the tube surface quality is improved. The ovality of the bent tube is small, and the intrados and extrados wall thickness are both thickened and changed uniformly, which indicates that the new process applied to form the very thin tubes is feasible.