By adding active driving function to the pressure plate or work
ring, the relative movement speed between the workpiece and
the grinding disc can be effectively controlled. This helps to
reduce the tendency of wear and deformation on the lapping
plate surface, allowing the lapping plate to maintain lapping
accuracy for a longer period of time. Additionally, the
controllability of the speed ratio between the lapping plate and
the work ring makes it more convenient to control the
workpiece profile. In some cases where flatness is extremely demanding, the
precision of the lapping process has reached its limit due to the
trajectory generated by conventional lapping actions. Further
breakthroughs are not possible. By adding the reciprocating
swinging function to the pressure plate or work ring, the
repeatability of the grinding trajectory can be further reduced,
thereby further enhancing the lapping precision.