(Dr. Steven Liang, advisor)

"Force Modeling in Reciprocate Grinding Based on the Wheel Topography Analysis"

Abstract

The magnitude of the forces in grinding relies on the process parameters (cutting velocities, depth of cut), but also on the topography of the wheel and the overall shape of the cutting edges. This understanding is important to the modeling and optimization of the grinding process.
The use of the Zygo microscope can provide an accurate three dimensional analysis of the grains, in order to characterize the topography of the wheel. Because of the reflectivity requirements in the acquisition of data with the ZYGO microscope, the topography is acquired measuring imprints of the wheel obtained with polished samples made of lead. The images are processed with a Matlab program to analyze the geometrical characteristics of the static grains. Characteristics such as the average grain size, the attack angle and the density as a function of the radial depth of penetration are obtained by modeling the grains into a conical shape. The random distribution of the grains is considered based on a statistical continuousdistribution.
The magnitudes of the total forces are derived from the modeling of the force per active grain, using the parameters from the topography and relying upon the expressions of the equivalent chip thickness and the volumetric wear rate. The model is calibrated the model with experimental data in surface grinding. The model validates experimental results obtained through machining carbon steel AISI 52100 (60 HRC) using a Norton medium size grit vitrified grinding wheel (5SG46IVS).

The knowledge of the forces level is relevant when estimating power consumption and surface integrity characteristics such as surface burning. It allows defining an acceptable range for the process parameters in function of the material properties and the wheel’s characteristics.