In the use of CBN grinding wheel, when the wear of grinding wheel width direction exceeds 80% of the total width of grinding wheel, the grinding wheel should be dressed. The dressing amount of grinding wheel is generally 0.01mm/ time, so the dressing method can be adopted by stages. CBN grinding wheel dressing mainly includes shaping and sharpening. The so-called shaping means that the grinding wheel keeps its original precision and geometric shape through dressing. The so-called sharpening refers to removing the binding agent contained in the grinding wheel grains, so that the grains have a certain height difference, so as to form a cutting surface, so as to facilitate bearing grinding.

DDG(Double Disc Grinding) machine mainly uses the high speed rotation of grinding wheel to grind the surface of the workpiece to achieve the accuracy. The working principle of different double disc grinding machine is also different.
1. Horizontal spindle double disc grinding machine with rectangular table: Use grinding wheel for peripheral grinding. The worktable reciprocates longitudinally, the grinding wheel rotates vertically, and the lateral feed is realized by the grinding wheel or the worktable.
2. Horizontal spindle double disc grinding machine with round table: Use the grinding wheel for peripheral grinding, the table is associated with rotary motion, and the rest of the working motion is realized by the grinding wheel.
3. Vertical spindle double disc grinding machine with rectangular table: The end face of the grinding wheel is used for grinding, and the table moves longitudinally and reciprocally. The grinding wheel with large diameter also moves vertically in addition to rotation.
4. Vertical spindle double disc grinding machine with round table: Also uses the end face of grinding wheel for grinding. Besides continuous rotation of the round table, it can also realize longitudinal reciprocating motion. The grinding wheel should move vertically in addition to rotation.

Ballast track is concrete or asphalt mortar to replace loose ballast and composed of track structure type, it has the characteristics of high track stability, good stiffness uniformity, strong structure durability and less maintenance work, for high-speed railway has a better adaptability than the traditional ballast track. Of slab without a frantic jumble track research in China is carried out along with the continuously go deep into the research of high speed railway, high-speed railway track plate is no ordinary concrete products, because of the complexity of the track plate used in concrete and the track plate size is relatively strict, must ensure that the support rail grinding machine precision steel erection error is less than 0.3 mm, Therefore, high requirements are put forward for the tool manufacturing industry.

A wafer goes through three changes before it becomes a real semiconductor chip: first, it is cut from a lump of ingots into wafers; In the second step, a transistor is engraved on the front of the wafer by the previous step. Finally, the wafer is packaged, that is, cut through the process to make a complete semiconductor chip. In this process, the wafer is cut into a number of hexahedral shape of the single chip, the process is called "Singulaton", and the process of Sawing the wafer into a rectangular shape is called "Die Sawing".

Double-disc grinding machine can grind workpieces using a through-feed, plunge-cut or oscillation process, depending on the respective requirements. The compact and rigid machine configuration ensures the greatest precision level of component with the shortest transfer times.

Through-feed process radial/linear for the shortest cycle times

The production of grinding vibration not only affects the machining accuracy, but also causes the workpiece surface roughness can not meet the requirements, so that many problems occur in the working state of the workpiece.

There are two reasons for the grinding vibration: one is the forced vibration of the workpiece; the other is that the machining parameters are unreasonable, which causes the self-excited vibration of the workpiece.

The first type of vibration exists in the environment, even if there is no grinding, the grinding machine is started, these vibrations exist. It happens that some vibration frequencies are close to the resonant frequencies of the workpiece, causing the grinding vibration marks. Suspected components that produce these vibrations include bearings mounted on rotating parts, driving belts, and hydraulic components.

The second type, is the role of periodic changes in processing, its frequency coincides with the resonant frequency of the workpiece, causing vibration. This kind of vibration can be reduced by adjusting the machining parameters. Or choose a low hardness, a bit of coarse grain grinding wheel. Because if the rigidity of the grinding machine is different, the sharp wheel can be used to reduce the grinding force, and the vibration grain can be reduced to a certain extent.