Determination of grinding conditions for renewal of a wheel cutting ability allowing for its variation during the machining process

Resumo

The authors discuss the determination of rigid-mode grinding conditions with a periodic electric discharge action on the wheel working surface in a separate zone, taking into account the in-process variation of the wheel cutting ability. The calculation is based on the mathematical relations that describe variation of the wheel cutting ability in elastic-mode infeed grinding with a constant workpiece-to-wheel pressing force, where the process kinematics is similar to that of the rigid-mode grinding. The workpiece speed is determined for a specified machined surface roughness. The workpiece-to-wheel pressing force is chosen such that the surface layer of the workpiece material should undergo no phase-structural transformations. The variations of the wheel cutting ability during the rigid-mode grinding are taken into account through the use of the equations that describe the variations of the wheel's current limited cutting ability in the elastic-mode grinding. Based on the discussion of various methods of calculation of one of the grinding parameters—depth of cut—the authors have found its value ensuring that no phase-structural transformations will occur in the surface layer of the workpiece material under maximum feasible removal rates.