Estimation of the active grains load in different kinematic variations of the internal cylindrical grinding process

Abstract

This article presents indexes referred to in literature and used when describing the working conditions of abrasive grains in internal cylindrical grinding processes: equivalent chip thickness heq, material removal rate Qw and the proper grinding material removal rate Q′w, as well as the average cross-section of the cut layer AD. From consideration of these indexes, it became apparent that there was a need to develop a new index which would synthetically combine all of the key grinding parameters, as well as the geometric structure of the grinding wheel active surface. A new index was defined, marked as SIQ (synthetic index of single abrasive grain material removal rate), in which the material removal rate Qw was related to the number of active grains on the grinding wheel surface and the converse speed ratio q = vs/vw. The work presents example calculations and charts detailing the changes within the SIQ index values for the following kinematic variations of internal cylindrical grinding processes: traverse grinding, reciprocating grinding, plunge grinding and plunge grinding with grinding wheel oscillations. The work includes an analytical and experimental example of how the SIQ index can be used to determine the grinding parameters within which the grain load remained at a similar level in various kinematic variations of the grinding process. The analyses performed show that application of the proposed index allows for: a comparison of various kinematic variations of internal cylindrical grinding, the selection of machining parameters in instances where the grinding kinematics may need to be altered, the necessity for maintaining the active grains load at the same level, determination of the changes of the active cutting vertexes load during the functioning of select machining parameters, and the comparison of grinding wheels with a variety of active surface geometric structures.