A molding composition for the manufacture of resinoid bonded abrasive structures is described. Each molding composition employs a high temperature thermosetting pre-polymer (or mixture of organic materials) containing aliphatically unsaturated imido radicals, which cures with essentially no evolution of volatiles to produce polyimide resin cross-linked with carbon-to-carbon and/or carbon-to-nitrogen bonds. The preferred molding composition embodies (in addition to the aforementioned type of pre-polymer) quantities of abrasive particles; particles of a strong, high thermal conductivity filler and solid lubricant particles. Grinding wheel composite structures produced from these molding compositions are particularly effective for dry grinding.
A process is described for manufacturing resin bonded grinding articles such as grinding wheels and segments. The process comprises preparing a mixture of abrasive grain particles, particulate spacer material and a curable liquid resin, filling a mold with the mixture and curing the mixture to a solid article in the absence of external pressure. Grinding articles prepared in this manner and containing high concentrations of abrasive grain particles exhibit superior grinding wheel performance in rate of stock removal with no metallurgical damage to the steel being worked upon while maintaining precision of cut.
An abrasive article such as a cup-shaped grinding wheel is provided, said grinding wheel having a cup-shaped support member of a cross-section providing an annular support surface to which is secured an annular abrasive member consisting of an annular polyimide resin-bonded diamond abrasive member and an annular back-up member of abradable porous polyimide secured to the inside surface of the annular polyimide bonded diamond abrasive member; the porous polyimide back-up member wears away in use and therefore obviates the need for dressing the grinding wheel.
A grinding wheel that can rotate at high speed to grind flat plates is comprised of a thin conical grindstone fastened to the open end of a rotatable inverted cup, with the grinding edge projecting outwardly from and at an inclined angle with respect to the open end. The grindstone includes a cylindrical fitting part which is fastened to the inside of the cup and a conical grinding part formed by electroplating from a nickel plating solution in which super hard abrasive grains are dispersed. The grindstone can also be prepared by electrodepositing abrasive grains directly onto a flange formed at the open end of the cup.
Abrasive articles and methods of making and using same are presented, the abrasive articles having a peripheral surface adapted to contact and abrade a workpiece. The abrasive articles comprise abrasives particles and a grinding aid composition positioned at an effective location in reference to the abrasive particles, the grinding aid composition comprising: a) a cured grinding aid binder comprising a blend of a thermoplastic resin and a thermoset resin, the thermoplastic resin and thermoset resin being present at an effective weight ratio; and b) an effective amount of a grinding aid dispersed in the grinding aid binder.
A method for accurately and economically shaping a zirconia workpiece with a relatively inexpensive silicon carbide grinding wheel is provided. The grinding wheel used in the method preferably utilizes 220 mesh silicon carbide particles bound in a low porosity vitreous matrix. The grinding wheel is then rotated at a sufficient speed to implement a grinding operation, and is engaged against the zirconia workpiece at a diametral feed rate of at least 0.04 mm/sec. The method advantageously removes material from the zirconia workpiece at a high rate of speed with minimal wheel wear, and results in accurate cuts and smooth surface finishes, and also eliminates the need for dressing the wheel prior to the grinding operation.
