METHOD FOR MAKING SMALL DIAMETER OPENINGS AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 2002 - IPC

FIELD: machine engineering, possibly manufacture of small-diameter openings in sheet blanks of composite fibrous material in different branches of national economy. SUBSTANCE: method comprises steps of applying efforts constantly oriented normally relative to blank plane for making finished opening; heating deformation zone until temperature less by (20-60)C than melting temperature of binder and at applying efforts normal relative to blank plane simultaneously applying oscillation efforts in direction parallel relative to blank plane. Apparatus includes punch with cone working portion, holder and die with built-in inductors. Punch is rigidly mounted by its upper end in tool-concentrator joined with ultrasonic device. Holder and die have annular turnings coaxial to guiding holes and having diameter equal to doubled diameter of guiding hole and depth equal to 1/8 of blank thickness. EFFECT: enhanced quality of parts made of composite fibrous material due to integrity of fibers, improved strength of punch. 3 cl, 4 dwg