The Flow Punch Forming
Process in Detail

Flow punch forming is based on a combination of axial force and relatively high speed, which results in heat from friction. The frictional heat and high contact pressure plastify the material. A high speed operation allows production of

Threaded bushes
Bearing bushes
Soldered bushes
Through-holes
Through-holes with sealing edges for round profiles

Because the material is compressed during this process, any threads formed subsequently have increased load capacity and can withstand tougher drawing forces. With centerdrill additional processes such as reinforcing welding, riveting down, or welding screw nuts into place are now a thing of the past. The special geometry of the centerdrill and the use of carbide allow a longer tool life up to several thousand forming operations.

Step 1

The point of the centerdrill is positioned so that it just touches the material, then it is pressed down on the material with high axial force and speed.

Step 2

Feed pressure and speed generate the necessary frictional heat of approximately 600° Celsius that is needed to render the material plastic and thus formable. The centerdrill penetrates the material in a matter of seconds.

Step 3

The centerdrill displaces the metal horizontally and vertically, whereby the material is displaced primarily downward, producing a bushing. The feed pressure decreases and the feed rate increases gradually as the centerdrill penetrates through the metal.

Step 4

The flow-punch formed bushing is now complete. The material displaced against the direction of feed has been transformed into a sealing edge in the form of a collar. This collar can be removed by cutting during the same operation with the centerdrill flat version that uses cutters ground into the belt

Step 5

The bushing is immediately ready without stock removal for chipless production of a thread using the centertap. The cold- formed thread increases the hardness of the material.

Step 6

The result: loadable connections that can withstand high drawing forces. Without drilling and subsequent riveting down or welding screw nuts into place.

The Flow Punch Forming Process in Detail