A method of grinding the edge of a disc uses a grinding machine having mounted thereon a grooved grinding wheel, in which the groove is formed in situ using a forming wheel also mounted on the grinding machine. After a workpiece has been ground or after a succession of workpieces have been ground, re-engaging the grinding wheel and the forming wheel with the grinding wheel remaining in situ, to re-form the groove in the grinding wheel to correct for wear. A grinding machine comprises a grinding wheel, drive means therefor, a workhead and workpiece spindle and drive means therefor, a forming wheel and drive means therefor, means for moving the grinding wheel so as to plunge grind the edge of the grinding wheel to form a groove therein of precise cross-section and means for effecting relative movement between the grinding wheel and the forming wheel to enable the grinding wheel to engage with the edge of a circular workpiece component mounted on the workpiece spindle to edge grind the component and wherein the forming wheel is also mounted on the workpiece spindle for rotation therewith, and the grinding wheel is a resin bonded wheel.
RELATED APPLICATION
This application is a division of copending U.S. patent application Ser. No. 09/194,706, filed Dec. 15, 1998, which is the national filing of International Application No. PCT/GB97/01569 filed Jun. 11,1997
Priority Data
Jun 15, 1996 [GB] 9612594 Dec 19, 1996 [GB] 9626397 Dec 19, 1996 [GB] 9626415
An apparatus for grinding a magnetic member comprises a cutting blade having a cutting edge including heat resistant resin and abrasive grain. A magnetic member including a rare-earth alloy is ground by the cutting blade while grinding fluid primarily made of water is supplied to a grinding region. A magnet separator having a surface magnetic flux density not smaller than 0.25 T magnetically separates sludge from used grinding fluid. Further, the grinding fluid is introduced into a tank, where the sludge contained in the grinding fluid is allowed to coagulate and sediment. The grinding fluid separated from the sludge is used in circulation. The same separation process can be used for separation of sludge containing a rare-earth alloy from waste fluid.
A method of positioning a grooved grinding wheel relative to a disc-like circular workpiece for edge grinding the workpiece using the groove in the wheel includes the steps of mounting the workpiece for rotation about a first axis, mounting the grinding wheel for rotation about a second parallel axis, effecting relative movement between the workpiece and the wheel to engage the rim of the wheel within the groove and performing a preliminary grind. The position of the wheel is axially adjusted in accordance with the measurements made on the profile of the rim produced by the preliminary grind, and the rim is ground again with a second preliminary grind with the grinding wheel located at the axially shifted position. The steps of grinding and measuring the periphery of the workpiece are repeated until the rim profile possesses the desired accuracy. The final position of the grooved grinding wheel is then utilized for grinding future wafers.
A method of grinding the edge of a disc uses a grinding machine having mounted thereon a grooved grinding wheel, in which the groove is formed in situ using a forming wheel also mounted on the grinding machine. After a workpiece has been ground or after a succession of workpieces have been ground, re-engaging the grinding wheel and the forming wheel with the grinding wheel remaining in situ, to re-form the groove in the grinding wheel to correct for wear. A grinding machine comprises a grinding wheel, drive means therefor, a workhead and workpiece spindle and drive means therefor, a forming wheel and drive means therefor, means for moving the grinding wheel so as to plunge grind the edge of the grinding wheel to form a groove therein of precise cross-section and means for effecting relative movement between the grinding wheel and the forming wheel to enable the grinding wheel to engage with the edge of a circular workpiece component mounted on the workpiece spindle to edge grind the component and wherein the forming wheel is also mounted on the workpiece spindle for rotation therewith, and the grinding wheel is a resin bonded wheel.
