With flow forming pursuant to DIN 8583, rotationally symmetrical hollow bodies are formed from a tube or bowl with a cylindrical, conical or curved surface line.
Flow forming in detail
A preform is slid onto the mandrel and clamped securely. As a rule, three or more rotating flow forming rollers press radially onto the rotating work piece, such that the material spreads in an axial direction. The wall thickness is thus reduced and the work piece is lengthened. The process is also frequently referred to as cylinder flow forming or stretching, whereby a distinction is made between forward and backward stretching. An essential criterion regarding the process to be used is the question of whether the workpiece is solely of tubular form or if it has a bottom and can be clamped. In the case of forward stretching, it is also possible to form teeth and so to produce a range of different internally toothed gear components.
Advantages of flow forming
The aim of flow forming is always to achieve a reduction in wall thickness. The final state is attained by pure compressive loading. The pressure applied to the material first of all serves to increase the work piece’s strength and also lengthens the material. The result is an extended work piece with enhanced material properties, a higher load-bearing capacity and a longer service life than components produced by metal cutting processes.