The Research On Dressing Of Resin-bonded CBN Grinding Wheels By Acoustic-optic Q-switched Nd: YAG Pulsed Laser

Dressing of resin-bonded CBN grinding wheels in orthogonal direction by acoustic-optic(AO) Q-switched Nd: YAG pulse laser has been studied from two respects of experiment and numerical simulation in this paper. Experiments on ablation and dressing of resin-bonded CBN grinding wheels by single laser pulse and by pulse laser respectively have been carried out to analyze dressing mechanism and disciplines of dressing effects influenced by laser and technology parameters. Geometric model of the wheels and thermal conduction model of single laser pulse ablating resin-bonded CBN wheels have been established. The numerical simulation results of ANSYS have verified that the model can describe the ablation process properly and offer guide for the experimental study and production.Resin-bonded CBN grinding wheels irradiated by AO Q-switched Nd: YAG single laser pulse with certain power density, its bonds get removed. The resin material in the bonds boils away while copper powder falls off in the form of solid state, which produces a crater, thus the CBN grits protrude and are not damaged.The essence of AO Q-switched Nd: YAG pulse laser dressing resin-bonded CBN grinding wheels in orthogonal direction is to overlap single ablation craters, by which ideal grains' protruding height and perfect wheels surface topography can be obtained. The study of dressing of resin-bonded CBN grinding wheels by pulse laser is based on the study of single laser pulse ablation, by which relationships between the ablation depth and laser parameters can be obtained as well as their influences on wheels surface topography, thus can obtain suitable pulse laser dressing parameters. Dressing of resin-bonded CBN grinding wheels by AO Q-switched Nd: YAG pulse laser through irradiating the wheels several times with these suitable laser parameters and reasonable process parameters can bring better dressing results than conventional mechanical and continuous wave laser dressing methods.Power density of AO Q-switched Nd: YAG pulse laser is the total parameter in the laser dressing process. The influences of laser average power, laser pulse repetition frequency and focal distances on dressing effect can reflect through laser power density. Numerical simulation with finite element software ANSYS taking laser power density as the only variable gets the temperature distribution around the irradiated zone and the relationship between laser power density and ablation crater depth. Numerical simulation results confirm that dressing of resin-bonded CBN grinding wheels by AOQ-switched Nd: YAG pulse laser has characteristics of little heat accumulation and small heat effect zone. Suitable laser power density range for dressing resin-bonded CBN grinding wheels can be obtained through numerical simulation, which can offer guide for experimental study and production.