Method for multiple cutoff machining of rare earth sintered magnet

A method for multiple cutoff machining a rare earth sintered magnet block using a multiple blade assembly comprising a plurality of cutoff abrasive blades coaxially mounted on a rotating shaft at axially spaced apart positions, each said blade comprising a core in the form of a thin disk and a peripheral cutting part on an outer periphery of the core, said method comprising the step of rotating and feeding the cutoff abrasive blades to cutoff machine the magnet block into a multiplicity of pieces,

• said method further comprising the steps of:
• setting the multiple blade assembly on one side of the magnet block such that it is movable parallel to a plane of rotation of the blades,
• rotating the blades,
• starting the machining operation of the magnet block and moving the multiple blade assembly from one end to an other end on one side of the magnet block to form cutting grooves in the magnet block,
• interrupting the machining operation at the other end on the one side of the magnet block before the magnet block is cut into pieces,
• moving the multiple blade assembly from the one side of the magnet block to an other side of the magnet block parallel to the plane of rotation of the blades, without moving the magnet block, and
• restarting the machining operation of the magnet block and moving the multiple blade assembly from one end to an other end on the other side of the magnet block to form cutting grooves in the magnet block until the cutting grooves formed from the one side and the other side merge with each other, thereby cutting the magnet block into pieces.