Apparatus and methods using the apparatus for treating metal wire

A method of treating a metal wire by multiple reverse bending comprising the following steps:

• providing an apparatus comprising a first roller having a first roller diameter, one or more intermediate rollers having intermediate roller diameters, and one exit roller having an exit roller diameter,
• wherein the first roller, the one or more intermediate rollers, and the exit roller form a sequence of rollers,
• wherein the first roller, the one or more intermediate rollers, and the exit roller each comprise a circumferential groove for receiving the metal wire, the circumferential groove being organized in one groove plane,
• wherein the exit roller diameter is larger than the first roller diameter, and
• wherein any one roller in the sequence of rollers has a roller diameter that is not smaller than a preceding roller in the sequence of rollers;
• continuously providing the metal wire having a metal wire thickness and a metal wire width,
• wherein the metal wire thickness is a smallest calliper size and the metal wire width is a largest calliper size when measured in all directions perpendicular to the metal wire, and
• wherein a ratio of the metal wire thickness to the metal wire width is smaller than 10;
• and
• running the metal wire through all or part of the sequence of rollers in a multiple reverse bending path from an entry roller to the exit roller,
• wherein the entry roller is the roller of the apparatus that that first bends the wire,
• wherein
• the entry roller is selected such that a ratio of a diameter of the entry roller to the metal wire thickness is between 20 and 50.