Working Process
  DRABUS frictiondrilling technology can be applied in one smooth movement.
The process itself can be subdivided into the following steps.

The example below describes the process of a type A DRABUS frictiondrill.
 
During step 1 the tool is pressed with a relatively high force against the workpiece in order to obtain initial frictional heat generation. This causes a plastic deformation of a maximum 5% of the total deformed workpiece material.
In step 2 the temperature of the tool and the workpiece increases substantially resulting in a decrease of the normal force required.
In step 3 the entire surface of the cone is in contact with the workpiece material and the temperature of the tool and workpiece reaches its maximum (depending on the workpiece material).
 
In the last step the outer bush is deformed. For this deformation a relatively high force is also necessary. 
This step is also called 'the calibration step'.