Estimation of material removal rate distribution in double-sided polishing of thick square workpiece considering workpiece attitude

A workpiece attitude during polishing process is known to affect material removal rate distribution, which is one of the most significant properties in polishing process. Though, the effect of the attitude in double-sided polishing process has not been discussed in the past literatures. Hence, a method for estimating the distribution in double-sided polishing of a thick square workpiece considering the attitude is developed, and the effect of the attitude to the material removal rate distribution is investigated utilizing the method in the present study. In the developed method, the attitude is identified based on the equilibrium of force and moment applied to the workpiece by the contact against upper and lower pads. And distribution of contact pressure between the workpiece and pads is calculated under the identified workpiece attitude. Then, the material removal rate distribution is estimated from the contact pressure distribution and relative velocity distribution, which is calculated from the conditions of geometry and rotational speed, based on Preston's law. It is confirmed that the material removal rate increases as the position is closer to the leading edge of the workpiece because of the workpiece tilt. And this variation increases as the workpiece becomes thicker and smaller. Therefore, it is confirmed that the effect of the workpiece attitude to the material removal rate distribution is significant, and considering the workpiece attitude is significant for investigating the material removal rate distribution in double-sided polishing of a thick or small workpiece.