Plastic bobbin and a method of manufacturing such a bobbin

A plastic disks (1), comprising a cylinder body (2) and a periphery of the flange for wherein the body (3), and is equipped with a u-shaped groove. Each end flange more than (3) is basically the radial direction flange unit is separated (4), wherein the flange element (4) along the cylinder body (2) are distributed. The manufacturing method of the bobbin, a a u-shaped groove with the injection moulding. The u-shaped groove production which is plural, wherein a side of the wall body of multiple are separated, wherein the wall element along the length distributed groove. Making the groove bending in order to form a cylinder body (2); and end part of the bending position that.