Modulated toolpaths for chip breaking

Researchers at UNC Charlotte and at the US Department of Energy's Y-12 National Security Complex have recently shown a new way to ensure chip breaking when turning. In NC machines, the toolpath can be modulated along the feed direction to cause interrupted cuts and ensure chip breaking. If the amplitude of the oscillation is too small, or if the timing is such that the waviness created on one rotation lines up with the wave created on a previous rotation, then the chip will be continuous and not broken. It is interesting that through amplitude selection and oscillation frequency, chip length can even be programmed. Because the oscillation is tangent to the desired surface, the chip breaking waviness appears in material that is later removed. This strategy works in all kinds of materials, from nickel alloys to polymers, and the chips always break.