Non-rotating or stationary dressing tools do not exhibit any movement in the peripheral direction of the grinding wheel. The grinding wheel profile originates by means of axial movement along the wheel contour, comparably to a turning process (Fig. 6-2).
Between the dressing tool and the rotating grinding wheel, there is a radial dressing feed rate of vfad. The dressing tool is set between two dressing strokes radially by the depth of dressing cut aed. For profile dressing, dressing tools with making contact in the form of a point or a line in the peripheral direction are usually the most suitable. The path of the dressing tool is controlled by NC programs or with older machine systems by means of profile guides.
 |
 |
 |
 |
stationary dressing tool
Fig. 6-2 Method kinematics — stationary dressing
For the mechanical dressing of common grinding wheels, diamond tools are used almost exclusively in the present day. Some examples of stationary diamond tools are:
single-grit dressing diamonds,
• dressing plates and
• multi-grain dressers (Fig. 6-3).
 |
 |
 |
stationary dressing tool
Fig. 6-3. Stationary diamond dressing tools
In single-grit dressers, an octahedral raw diamond is soldered into a steel holder. The diamond gets worn after a long period of use. In this case however, we can re-solder it, bringing another tip of the octahedron into action. The engagement width or effective width, which increases due to wear, sensitivity to impact, high temperatures, and high cost are disadvantages of larger raw diamonds. In order to create more complicated grinding wheel contours, the diamond can also be sharpened (profiled diamond). However, re-soldering is not possible as it is in the case of octahedral single-grit diamonds.
Instead of monocrystalline diamonds, small rods composed of polycrystalline diamond (PCD) or chemical vapoured diamond (CVD) are being increasingly used. Their advantage is that the hardness anisotropy of their smaller monocrystals is balanced out in them. They are thus quasi-isotropic and do not have a preferred direction [KOEN80, LIER02, SEN02, TOEN00]. Under the designation MCD, monocrystalline diamonds are applied in dressing technology that have been synthesised in the form of small rods. The advantage of MCD is that its geometry does not change with wear [COEL01, LIER02, TOEN00]. Depending on the orientation, the properties of only one crystal plain are dominant [KUCH03].
The dressing plate, like the single-grit dresser, is suited to producing simple shapes. Diamond material is arranged in a single plane in these tools. The plate is brought into contact with the grinding wheel tangentially in the peripheral direction, such that several diamonds are available to produce the desired wheel topography. Since the grinding wheel grinds into the at first straight-edged dressing plate and only produces a circular profile after several cycles, the dressing result changes in this phase. The dressing parameters have to be altered accordingly until a quasi-fixed state has been reached.
The multi-grain dresser, on the other hand, possesses a spatial arrangement of diamond chips and allows higher dressing feeds due to the larger effective width. However, only flat surfaces can be dressed, and the dressing results are not exactly predictable.
If no automatic dressing possibilities exist, manual dressing tools are utilized for the tool preparation of conventional grinding wheels. Operator safety can be endangered by manual interference with the rotating grinding wheel.
Especially when preparing superabrasive grinding wheels, stationary dressing tools have the considerable disadvantage that only few diamonds engage with the grinding wheel. In this way, these tools are subjected to a large amount of wear, leading to shape defects in the grinding wheel surface. Therefore, stationary dressing tools are seldom used for dressing superabrasive grinding wheels.