Single Point Diamond Dressing is a common method for dressing vitrified bond grinding wheel. This dressing method often leads to unstable grinding wheel performance, so the dressing method and procedure should be adjusted accordingly. When grinding the workpiece, the typical method is: rough grinding a certain machining allowance with the grinding wheel, then changing the dressing parameters, and then fine grinding the workpiece.
Generally, during rough grinding wheel trimming, the diamond is rapidly cross fed along the outer circle of the grinding wheel, while during fine trimming, the cross feed speed of the corrector is greatly reduced to obtain smooth grinding wheel surface and workpiece surface. A repair method called "overlapping" or "partially overlapping" can ensure correct and stable repair. For example, a wheel with a diameter of 406.4mm, a speed of 6000sfm (1828m/min), a single point diamond corrector's arc radius of 0.254mm for rough grinding and dressing, and the dressing amount of each stroke is 0.025mm.
The cross feed speed commonly used in general correction is often too fast, so that part of the grinding wheel surface cannot be repaired. The surface of the grinding wheel can be repaired by multiple strokes, but the surface is uneven. This kind of grinding wheel has high grinding performance, but its wear is fast and uneven. Grinding wheel dressing is generally carried out at grinding speed. The only exception is that the scraping, shaping and trimming are carried out at a low speed of 300 sfm (91.44 m/min).
The cross feed speed shall be calculated and determined according to the diamond size of the dresser and the requirements for the surface of the grinding wheel. Generally, 2~3 laps are used for rough grinding, and 4~6 laps are required for fine grinding. Calculation of cross feed speed of corrector: known diamond arc radius (XB=0.015”), diamond penetration (0.001”), and grinding wheel speed of 1400rpm. The distance CB is calculated as follows: XB=0.015”, CX=0.015” - 0.001”=0.014”. CB=0.00735, while AB=2CB=0.0147”.
In this way, the feed pitch of diamond per revolution is obtained to ensure that there is no unfinished part on the surface of the grinding wheel. Converted to the feed speed AB per minute ×1400rpm=20.58ipm。 This speed enables the diamond to cover the whole wheel surface in one dressing. If the trimming requires secondary lapping, the feed speed is halved to 10.29ipm. It is ideal for rough finishing. Fine finishing requires 4~6 times of lapping, and the feed speed should be reduced accordingly. For example, it is 5.14ipm for 4 times of lapping.
Post time: Jan-28-2023