Production of short metal fibers

Process for producing short ultra-thin metal fibers having a cross-sectional dimension of less than 200 microns by directly cutting a metal block having a surface comprising the steps of:

• (a) rotating said metal block such that said surface is moving at a cutting speed;
• (b) contacting a cutting edge of an elastic tool to said surface at an entering cut, the cut having a width corresponding to a length of the fibers to be obtained, said elastic tool upon such contact self-generating self-excited vibrations;
• (c) feeding said elastic tool towards said surface at a feed rate such that
• (1) said cutting edge is dislocated in a feed force direction,
• (2) the amplitude of said self-excited vibrations is larger that said feed rate,
• (3) said cutting edge separates from said surface once per cycle of each self-excited vibration, and
• (4) the cutting loci of the cutting edge contacting said surface are equal in n times and n+1 times of cutting,
• to finely cut, break, and separate said fibers from said surface;
• (d) and wherein the rake angle of the cutting edge is between 0.degree. and a negative angle;
• and in accordance with the material nature and thickness of fibers to be produced, the cutting speed is determined between 20 and 200 m/min, the feed rate between 0.001 and 0.02 mm/rev, and the self-excited vibration between 1 and 7 KHz, thereby producing a needle-shaped fiber in each cycle of said self-excited vibrations having said cross-sectional dimension and having a length corresponding to said entering cut, each said fiber having a smooth, bright face, a rugged face, and a destroyed face.