In-process monitoring of microscale grain protrusions by tracing impulse-discharge energy related to thermal transmission balance on diamond cutting interface

Abstract

Stable ground surface depends on abrasive grain protrusions, but it has no way to monitor the wheel topographical state during grinding. Generally, the charge coupled device (CCD) monitoring is employed to on-machine measure 2D grain protrusions, but the whole wheel micro-topography has not been recognized in-process. In the electro-contact discharge (ECD) truncating of diamond wheel, a thermal transmission balance on diamond cutting interface is proposed to identify the diamond thermochemical removal. Accordingly, the impulse-discharge energy is characterized by discharge waveforms to relate to the microscale grain protrusion topography. The objective is to advance surface grinding by in-process monitoring the whole protrusion topography rather than by on-machine measuring the partial wheel topography. First, the grain top height and area were modeled by the microscale spark-discharge gap and the microsecond grain truncating duration, respectively; then, the influence of kinematic variables and electrical variables on discharge parameters was analyzed to regulate the impulse-discharge energy; finally, the thermochemical removal rate was traced along with the grain protrusion parameters for ground surface quality. It is shown that the diamond thermochemical removal may be regulated by kinematic variables and electrical variables. At the dynamic thermal transmission balance of impulse-discharge energy on diamond cutting interface, the thermochemical removal rate gradually tends to zero, leading to stable grain top height and area for a stable ground surface. As a result, the grain top height and area on the whole wheel surface may be monitored under the critical discharge parameters in relation to grain size during ECD truncating.