centerdrill Standard Flow Punch Former

The standard versions include the centerdrill short and long models. They differ only in the length of the cylindrical part; the angle of the conical part is identical. When using these versions the material displaced against the direction of feed remains on the surface of the workpart and forms a collar.

Both models are also available in the flat version, with cutters ground into the belt that remove the collar in
the same operation, resulting in a smooth surface.

 

 

Design of the centerdrill
Flow Punch Former

The centerdrill flow punch former consists of a centering point, a tapered and a cylindrical forming piece, a belt, and a support shank. Based on this design principle, several standardized flow punch formers were developed for different purposes. They vary basically in the length of the cylindrical forming piece and the design of the belt area.

 

Which centerdrill model for which Application?

 

The selection of the appropriate flow punch former basically depends of the respective metal and its wall thickness, of the desired surface (plane or with collar) and whether a bushing shall be formed for a thread or a rim hole.

 

Bore hole for M8 threads with collar:

Short version: if a M 8 thread shall be formed into a 2mm thick sheet of S235JR (St37/2) we recommend using the short Ø 7,3mm flow punch former – a former, in which the cylindrical part is only that long that the resulting bushing will be slightly tapered at the run-out.

 

Long version: if the same application shall be realized in a 3mm thick sheet we recommend using the long Ø 7,3mm centerdrill type since this version would not form the bushing correspondingly due to the shorter cylindrical part

 

Bore hole for M 8 thread with plane surface
(without collar):

Short/long version: If the surface of the work piece to be processed shall be plane and/or flat we recommend using the short-flat or long-flat centerdrill type.

 
Through boring:

If a through boring is to be formed we generally recommend the long centerdrill type since it fully forms the bushing by means of its extended cylindrical part.

 

 

 

Flow Punch Forming Tools
in Special Design

If our standard products cannot be used or are not adequate for your specific application, we also manufacture custom flow punch formers according to drawings. We will be happy to consult with you regarding your special requirements. The following are examples of such special designs:

 

Cut-off tip	Pointed angle
Rounded tip	No belt
Extended cylindrical working part	No cylindrical working part
With drill tip	With swirl