Material removal rate prediction and surface quality study for ultrasonic vibration polishing of monocrystalline silicon

Ultrasonic vibration polishing (UVP) which integrates mechanical polishing and ultrasonic vibration technologies is applied to process monocrystalline silicon. The predictive model for material removal rate (MRR) is developed which includes the microscopic contact among the workpiece, abrasive grains, and polishing pad, the scratch effect of embedded abrasive grains, and the impact removal of free abrasive grain on the workpiece surface. This model unveils the reasons for the enhancement of MRR and the effect of different parameters on MRR during UVP. UVP experiments of monocrystalline silicon were carried out to validate this model. It is found that the MRR model is in excellent consistency with the measured MRR and the error rates could be controlled to less than 10%. The increase in spindle speed and ultrasonic amplitude increases the kinetic energy of the abrasive grains. The increase in abrasive grain size improves the contact area between the abrasive grains and the workpiece. Therefore, these contribute to the MRR of the UVP. In addition, different polishing parameters (spindle speed, ultrasonic amplitude, and abrasive grain size) were analyzed and compared on the surface roughness and microscopic local morphology. This work not only offers a novel method for predicting the machining efficiency of UVP but also provides an excellent reference for the evolution of ultrasonic vibration-assisted technologies.