| abstract |
A composite, polymer bonded abrasive wheel is disclosed for grinding operations and especially for use with multiple station, glass beveling machines. The abrasive wheel breaks in quickly and delivers consistent performance with little or no dressing needed over the entire life of the wheel. In one aspect, the novel abrasive wheel includes a concentrically mounted, annular abrasive rim on a cup shaped hub. The rim can contain an abrasive such as diamond or cubic boron nitride which is embedded in a bonding composition that includes amino aldheyde and phenolic thermoset polymers, a plasticizer, and optionally filler. The hub includes a crosslinkable, strong and rigid, engineering polymer, preferably melamine phenolic thermoset polymer, mixed with spodumene in amount effective to make the coefficient of thermal expansion of the hub match that of the rim. The wheel can be made by simultaneously hot pressing rim and hub preforms and without an additional baking step. Optionally the rim and hub can be colored to identify the characteristics of the abrasive, and to help determine that the grinding surface has worn down to the hub. |