Experimental Study Of Laser Dressing Superabrasive Grinding Wheels

Superabrasive grinding wheels have excellent properties and are applied in many fields. The application of superabrasive grinding wheels is the foundation of precision and ultra-precision grinding, high-efficiency grinding and automatic grinding. But the dressing of superabrasive grinding wheels is difficult. Conventional dressing methods and other methods have disadvantages, which limits the application of superabrasive grinding wheels. In order to utilize the excellent properties of superabrasive grinding wheels sufficiently, raise the application level of superabrasive grinding wheels and promote the development of grinding technology, new dressing way needs researching. Laser dressing is not touching way and keeps off force action, so it is promising way. But, laser dressing is not applied in practice now, it needs further researching as a new dressing way. YAG laser is used to do experimental study of laser dressing superabrasive grinding wheel, the following contents have been done in this thesis:(1) A three-dimensional unsteady state heat conduction model to compute the threshold of laser dressing is presented, the ablation threshold of resin and metal bond under single laser pulse act is computed, the breakage threshold of diamond and CBN is computed. These supply foundation for choosing proper dressing parameters.(2) The dimension of single pulse ablation craters plays an important role in the dressing effect, so this thesis researches the disciplines of dimension of craters single pulse ablated influenced by pulse width, output power and defocus distance, the craters are observed with microscope and the diameters of craters are measured by means of CCTV (Closed Circuit TV Viewing) system. Then, the result of experiment is analyzed from heat conduction and the power distributing.(3) The overlap coefficient experiment of ablation craters is done, then proper overlap coefficient for getting uniform dressing surface topography of wheel is chosen. According to the result of front experiments, proper dressing parameters are chosen by the experiment of laser single pass scanning. And the experiment of auxiliary gas is done, good effect is got when dressing resin bond grinding wheel with auxiliary coaxial gas, good effect is got when dressing metal bond grinding wheel with auxiliary coaxial and side blowing gas that prevent re-solidified metal from covering abrasive.(4) According to the result of front experiments, the parameters to dress grinding wheel are optimized. The surface topography of grinding wheel dressed by laser is observed bymeans of SEM (scanning electronic microscope), the grinding force of grinding wheels before dressing and after dressing is measured and compared. The results show that laser dressing is feasible and suitable dressing parameters can be selected by the experimental way in this thesis.The work in this thesis supplies experimental and theoretical foundation for application of laser dressing, and this thesis presents a way of selecting laser dressing parameters fast, which can guide the application of laser dressing.