Shrink and Press Fitting

Shrink fitting is accomplished by heating a part so that a hole in it expands, after which another piece may be fitted, usually under pressure, into that hole. The outer piece then contracts as it cools, creating a tight seal. Some sinter-like bonds may form, but shrink fitting works primarily by friction bonding. It requires thermal energy and less force is needed to achieve the final bond. If the material to be shrink-fitted is metallic, heating may be accomplished by induction.

Press fitting is similar to shrink fitting except that parts are not heated and higher pressures are necessary. Press fitting requires less energy but the bond is weaker. Also, if bonded material has a buckling problem press fitting is not suitable as a joining technique.