Patent ID: 9033762
Filing Date: 2015-05-19
Classification: B24B,Y10T

Abstract:
1. A method for preventing a slip of a work piece in a grinding machine that includes: a master main spindle provided with a center that supports one end of the work piece; a slave main spindle provided with a center that supports the other end of the work piece; and a master servo motor and a slave servo motor that synchronously drive the master main spindle and the slave main spindle for rotation, wherein at least one of the center provided for the master main spindle and the center provided for the slave main spindle is pressed toward the other one of the centers to generate friction forces between the work piece and the centers to thereby synchronously drive both ends of the work piece for rotation, and, in this state, a wheel head is caused to cut into the work piece to grind the work piece, comprising: before grinding, executing a slip detection cycle that detects a limit current value for the servo motors, at which the work piece and the centers slip, and during grinding, when any one of current values of the servo motors has reached a slip threshold value computed on the basis of the limit current value, changing a grinding condition to prevent a slip between the work piece and the centers in advance, wherein the slip detection cycle is configured to rotate at least one of the master main spindle and the slave main spindle by a corresponding one of the master servo motor and the slave servo motor to thereby detect the limit current value at which the work piece and the centers slip.