CBN abrasives are expensive abrasives. The wheel manufacturer must provide a dressing method that consumes as little abrasive as possible so that the user can grind as many workpieces as possible before discarding the wheel. Normally, only a few microns can be removed to make the CBN grinding wheel sharp again. We found in the grinding test that the ratio of the dressing feed rate to the dressing speed has a great influence on the particle fracture characteristics. The dressing speed ratio refers to the ratio of the linear speed of the dressing wheel to the linear speed of the grinding. The speed ratio means that in the dressing contact position, the grinding wheel and the dressing wheel rotate in the same direction. At the same time, the manufacturer must find an effective way to make the cutting edge of the abrasive grain stand out. We use B64 CBN grinding wheel from Telly Company in Austria as a typical research abrasive. According to reports, the level of synthetic defects of grinding wheels is controlled at the sub-micron level. Telecom can change the fracture characteristics of abrasive particles, and can produce abrasives with well-controlled fracture strength. In the research on the B64 type ceramic bond CBN grinding wheel, the grinding wheel is dressed by a rotating diamond grinding wheel with a speed ratio of +0.2. When the dressing amount is 1 μm, the CBN abrasive grains retain the CBN abrasive grains, so microscopic cracks appear. A large number of cutting edges are concentrated on the surface of the abrasive particles, and micro-cracks are conducive to the sharpness of the grinding wheel. When the amount of trimming increases to 2 to 3 μm, obvious macro cracks appear. When macro cracks appear, important parts of the abrasive particles will be lost. As a result, there are few sharp cutting edges on the surface of the grinding wheel, which can produce many poor cutting surfaces. A large number of expensive abrasive particles fall off and cause the surface abrasive particle density to decrease, which shortens the service life of the grinding wheel and reduces the cost performance. These results indicate that small changes in the beneficiation feed can easily affect the effect of the beneficiation process. In order to make the necessary fine-tuning, CBN users must have a high-resolution dressing feed mechanism.

The result of changing the dressing rate is similar to changing the dressing depth. Because the dressing force caused by the dresser and the grinding wheel rotating in the same direction is greater than the normal grinding force, the dressing removes more ceramic bond and fewer abrasive particles. When the dressing rate is increased from +0.2 to +0.8, more bonding agent is removed, and the macroscopic cracks of the abrasive grains are also intensified at the same time. Even when the feed depth is 1 μm, a large part of the abrasive grains have been broken. Based on the above results, users cannot think that the higher the speed ratio, the better just because the high dressing speed ratio removes more binder. If the high-speed ratio exacerbates the macro cracks, then the dressing of the grinding wheel will cause accelerated wear of the grinding wheel.

During the dressing process of the large-size grinding wheel for grinding the outer cylindrical surface, it was also found that the change of the grinding wheel from micro cracks to macro cracks caused by increasing dressing speed ratio and feed depth should cause special attention, because large abrasive grains are more likely There are defects that will become the starting point of cracks in the future. When we observe large cracks, it is easier to distinguish the differences between the two types of cracks.

Through some other studies, we realized the importance of using a suitable dressing rate to ensure proper contact between the dressing wheel and each abrasive grain on the CBN grinding wheel. Ideally, one abrasive grain can only be sharpened by one diamond on the dressing wheel. If the number of diamonds for each abrasive grain is less than one, the dressing will miss some dull abrasive grains that have not been sharpened.

Generally speaking, the rotation of the dressing wheel causes the diamond to act on each abrasive grain more than once, that is, each abrasive grain effectively dresses more than once. Since the surface of the abrasive grains, each sharpening action after the first time is performed under the condition of micro-feeding. The multiple sharpening effects caused by the feed rate produce a relatively unsharp surface. After years of research on the sharpening effect of grinding wheels, we have re-modified the design of the dressing device. We found that it is relatively easy to obtain a good dressing effect and to further calculate the appropriate dressing speed for a given wheel speed and CBN abrasive grain size.

We carefully studied the surface of the ceramic bond CBN grinding wheel after dressing and use, and found that the dressing made the density of the CBN abrasive grains and the ceramic bond in the surface layer of the grinding wheel lower than other parts of the grinding wheel. Ordinary grinding wheels with vitrified bond will also have such a surface layer, which is called a surface metamorphic layer. This surface layer can be from a few microns to 30 microns deep. With the use of the grinding wheel, the depth of the metamorphic layer will continue to increase, and the effect on the surface of the grinding wheel will continue to increase.

The dressing of the grinding wheel after use can eliminate the increasingly deepened and more harmful surface metamorphic layer during use. Since the dressing feed depth of the ceramic bond ordinary grinding wheel is much greater than that of the ceramic bond CBN grinding wheel, especially the dressing condition of the ceramic bond ordinary grinding wheel, the dressing feed depth ensures that almost all the grinding metamorphic layers are removed, resulting in A new surface layer composed of abrasive grains and binder determined only by the dressing parameters. However, when dressing the ceramic bond cubic boron nitride grinding wheel, the dressing feed depth may be much smaller than the metamorphic layer, which seriously affects the performance of the dressing wheel.

　　To completely repair the CBN grinding wheel, the user must have a dresser with a large feed depth. We also found that compared with a 2 micron trimming, when the trimming is divided into four times with a total feed of 2 microns, the macro cracks are smaller and the metamorphic layer is eliminated.