Method for Calibrating the Measurements of an Annular Body

A method for calibrating the internal measurements of an in particular annular body comprising a partially crystalline or thermoplastic plastic, the method comprising:

• inserting the annular body into a receiving device;
• introducing of an oscillating body into the interior of the annular body with axial advancement with simultaneous excitation of the oscillating body (20, 30, 32) to mechanical oscillations;
• locally heating the annular body to at least the glass transition temperature of its material by mechanical transmission of these oscillations to the annular body;
• continuing the axial introduction of the oscillating body until a calibration portion of the oscillating body plunges into the annular body;
• cooling the annular body to a temperature below the glass transition temperature of its material;
• and
• optionally removing the annular body from the receiving device after a retraction of the oscillating body.