This type of shaping mainly relies on the compressed air introduced into the profile from the core die of the machine head.
Generally, the air pressure reaches 0.02 to 0.1 MPa, so that the profile surface can be completely attached to the cavity surface of the shaping device.
Because there is a certain pressure inside the profile, and the contact time between the profile and the sizing device is longer, when this sizing method is adopted, a profile with a higher external surface dimensional accuracy and a brighter surface can be obtained.
