Abrasive tools suitable for precision grinding of hard brittle materials, such as ceramics and composites comprising ceramics, at peripheral wheel speeds up to 160 meters/second are provided. The abrasive tools comprise a wheel core attached to an abrasive rim of dense, metal bonded superabrasive segments by means of a thermally stable bond. A preferred tool for backgrinding ceramic wafers contains graphite filler and a relatively low concentration of abrasive grain.
A feedstock for creating cutting tools comprises a mixture of diamond particles, a binding material and a homogenizing agent that maintains the mixture of the diamond particles and binding material. In one present embodiment of the invention, the feedstock comprises diamond particles mixed with a binding agent of a brass powder and a wax or plastic homogenizing agent. The feedstock of the present invention is useful in making many types of abrasive cutting tools. One such cutting tool is an atherectomy burr for use in removing occlusions from a patient's blood vessel. A cutting tool made of the feedstock of the present invention has improved thermal conductivity compared with conventional atherectomy burrs.
An abrasive article including from about 40 to about 80 volume percent interconnected porosity, the article being useful as a segment for a segmented grinding wheel, and a method for fabricating the same. The method includes blending a mixture of abrasive grain, bond material and dispersoid particles, the mixture including from about 40 to about 80 volume percent dispersoid particles. In one embodiment the mixture includes from about 50 to about 80 volume percent dispersoid particles. In another embodiment the mixture includes an organic bond material and from about 40 to about 80 volume percent dispersoid particles. The powder mixture is then pressed into an abrasive laden composite and thermally processed. After cooling the composite is immersed into a solvent, which dissolves substantially all of the dispersoid particles, leaving a highly porous, bonded abrasive article.
An abrasive article including from about 40 to about 80 volume percent interconnected porosity, the article being useful as a segment for a segmented grinding wheel, and a method for fabricating the same. The method includes blending a mixture of abrasive grain, bond material and dispersoid particles, the mixture including from about 40 to about 80 volume percent dispersoid particles. In one embodiment the mixture includes from about 50 to about 80 volume percent dispersoid particles. In another embodiment the mixture includes an organic bond material and from about 40 to about 80 volume percent dispersoid particles. The powder mixture is then pressed into an abrasive laden composite and thermally processed. After cooling the composite is immersed into a solvent, which dissolves substantially all of the dispersoid particles, leaving a highly porous, bonded abrasive article.
Abrasive tools containing high concentrations of hollow filler materials in a resin bond are suitable for polishing and backgrinding of hard materials, such as ceramic wafers and components requiring a controlled amount of surface defects. These highly porous abrasive tools comprise fine grit abrasive grain, such as diamond abrasive, along with the hollow filler material and resin bond.
A method for thinning (such as in grinding and polishing) a material surface using an instrument means for moving an article with a discontinuous surface with an abrasive material dispersed between the material surface and the discontinuous surface where the discontinuous surface of the moving article provides an efficient means for maintaining contact of the abrasive with the material surface. When used to dimple specimens for microscopy analysis, a wheel with a surface that has been modified to produce a uniform or random discontinuous surface significantly improves the speed of the dimpling process without loss of quality of finish.
