Abstract: An experimental study on cutting material at nanometer scale is conducted by applying the principle and technology of scanning probe microscope (SPM). It is revealed from the experiments that cutting inside SPM is an excellent and direct way to research the material removal process at small size. Based on the experimental results，the mechanism for the chip formation in the cutting of amorphous alloy is discussed. It is found that the deformation along the direction of chip flow occurres at first before localized shear really happened，and a simplifying geometrical model is proposed to illustrate the deformation.

Key words: Chip formation, Nano-machining, Scanning Probe microscope, characteristics investigation, organic Rankine cycle, twin screw expander