Grob-Forming

The Grob cold forming procedure is based on the principle of breaking up the general forming work to be produced into many individual forming steps. A pre-form (e.g. deep-drawn bowl) is pushed onto an interlocked tool mandrel and fastened with a pressure plate. Two rollers facing the mandrel on either side rotate around one axis each to form the pre-form according to their geometry and that of the tool mandrel by plastically deforming the material by touching the outer-most point of their circle. The mandrel is turning synchronously in time to the rotating rollers so that rotation of the rollers by 360° according to the rotating angle of the mandrel to the component area to be formed subsequently, takes place. At the same time as the rotating movement, the mandrel is evenly axially advanced so that the pre-form is formed in the axial direction via the workpiece height to be produced.