PHASE FOCUSING METHOD FOR SCREW-LIKE GRINDING WHEEL AND APPARATUS THEREFOR

PROBLEM TO BE SOLVED: To provide a phase focusing method for a screw-like grinding wheel and an apparatus therefor, capable of precisely performing phase focusing of a screw-like grinding wheel by highly precisely detecting contact and non-contact states of the screw-like grinding wheel. SOLUTION: In performing phase focusing of the screw-like grinding wheel 14 relative to a disc dresser 32 prior to engagement of the screw-like grinding wheel 14 with the disc dresser 32 during dressing, it is determined whether or not the screw-like grinding wheel 14 is in contact with the disc dresser 32 based on a voltage V in response to an elastic wave of the screw-like grinding wheel 14 in contacting the disc dresser 32. When the voltage V is not in excess of a threshold value Vo even if the screw-like grinding wheel 14 is in contact with the disc dresser 32, the rotational speed of the disc dresser 32 is raised for determination of a forced contact and, based on the phase of the screw-like grinding wheel 14 at this time, the screw-like grinding wheel 14 is positioned at an engageable middle phase. COPYRIGHT: (C)2010,JPO&INPIT