Tool for machining a cmc by milling and ultrasonic abrasion

Abstract

The invention relates to a tool for machining hard materials such as metal-matrix or organic-matrix composite materials, comprising a cylindrical sonotrode ( 22 ) connected, along the axis (A) of said cylinder, to an assembly vibrating at a predetermined ultrasonic frequency and rotated about said axis, and at least one nozzle ( 3 ), on the surface to be machined and at the terminal end ( 24 ) of the sonotrode, for ejecting a liquid in which abrasive particles are suspended, said particles being vibrated at said ultrasonic frequency by the sonotrode so as to form a drilling head along the axis (A) of the cylinder, characterized in that the circumference ( 23 ) of the sonotrode is covered with particles of a so-called superhard material in order to form a milling head capable of moving in a plane that is substantially perpendicular to said vibratory axis (A).

1 . A tool for machining hard materials such as metal-matrix or organic-matrix composite materials, comprising a cylindrical sonotrode ( 22 ) connected, along the axis (A) of said cylinder, to an assembly vibrating at a predetermined ultrasonic frequency and rotated about said axis, and at least one nozzle ( 3 ) for ejecting, on the surface to be machined and at the terminal end ( 24 ) of the sonotrode, a liquid in which abrasive particles are suspended, said particles being vibrated at said ultrasonic frequency by the sonotrode so as to form a drilling head along the axis (A) of the cylinder, 
       characterized in that the circumference ( 23 ) of the sonotrode is covered with particles of a so-called superhard material in order to form a milling head capable of moving in a plane that is substantially perpendicular to said vibratory axis (A). 
     
     
         2 . The tool as claimed in  claim 1 , in which the so-called superhard material is polycrystalline diamond. 
     
     
         3 . The tool as claimed in  claim 1 , in which the so-called superhard material is cubic boron nitride. 
     
     
         4 . The tool as claimed in one of  claims 1  to  3 , in which said abrasive particles are made from boron carbide. 
     
     
         5 . The tool as claimed in one of  claims 1  to  3 , in which said abrasive particles are made from polycrystalline diamond. 
     
     
         6 . A method for machining hard materials such as metal-matrix or organic-matrix composite materials, using a tool as claimed in one of  claims 1  to  5 , the sonotrode ( 22 ) vibrating in a direction (A) substantially perpendicular to the surface to be machined, and moving in a plane that is substantially perpendicular to its vibration direction. 
     
     
         7 . The method as claimed in  claim 6 , in which the sonotrode ( 22 ) is vibrated at a frequency that is substantially equal to 20 kHz. 
     
     
         8 . The method as claimed in either of  claims 6  and  7 , in which the speed of rotation of said sonotrode is between 10 000 and 40 000 rpm. 
     
     
         9 . The method as claimed in one of  claims 6  to  8 , in which the tool operates in successive cuts, the depth of each cut being 0.5 mm or less. 
     
     
         10 . The method as claimed in one of  claims 6  to  9 , in which the axial feed rate is greater than 500 mm/min. 
     
     
         11 . The method as claimed in  claim 10 , in which the axial feed rate is between 500 and 1000 mm/min.