Research on the ultra-precision ductile cutting mechanism of KDP crystal

To achieve ductile processing of brittle materials is a key factor to obtain high quality finished surface. A new strategy was carried to clarify the brittle-to-ductile transition mechanism. The KDP crystal was processed by a mono diamond tool with arc-nose, and the plastic deformation can be found in the inside chip by optical microscope, also apparent transitional zone of brittle fracture to plastic deformation along the width direction of chips. It can be inferred that the width of plastically deforming area is sensitive to the cutting parameter feedrate. The critical cutting thickness was calculated by the parameters measured from the chips. At last a new model for calculating the critical cutting thickness of KDP crystal was given.