It also reduces the thermal stresses that are always present.
Stretching is done by gripping the ends of the entire runout extrusion length and stretching it by around 1% using a hydraulic piston.
This operation establishes the final profile dimension after pressing. Stretching affects profile shape, particularly for flange angles and gap openings in semi-open profiles.
In certain instances, these dimensions may be calibrated in conjunction with the stretching operation.