Corundum appears as polycrystalline material and is broken down to the desired grit sizes. The size of the single crystals within the larger abrasive grits depends on the manufacturing route. Pink corundum appears as blocky grits with sharp edges and an average crystal size of 750 pm [WASH12b]. Zirconium corundum can have much smaller crystal […]
Рубрика: Life Cycle and Sustainability of Abrasive Tools
More Synthesis Methods
Besides a direct transformation of graphite into diamond and the most common synthesis technique with molten catalyst, there are more synthesis methods [WEDL77]. These are Shock Wave Synthesis, growth from carbon molt and chemical diamond deposition from gas phase (Chemical vapor deposition, CVD). During CVD synthesis, carbon-containing gas like methane is disintegrated in presence of […]
Sifting
Sifting is a separating procedure where the falling particles are exposed to a contrary flow [SALM07, p. 134]. If the flow rate meets the falling velocity of a certain particle size, these particles hover. Smaller particles stay in the flow, coarser particles decant. One method is to suspend the particles in an aerosol beam and […]
Polyamide and Polyimide Resin
Polyimides are polymers with a noncarbon atom of nitrogen in one of the rings in the molecular chain (Fig. 3.4) [HARP03, p. 432 f.]. Polyamide-imide are members of the same polymer family and contain aromatic rings and nitrogen linkages (Fig. 3.4) [HARP03, p. 432 f.]. Polyamid and polyimide bondings have a higher toughness, thermal resistance […]
Metallic Single-layer Bonds
3.4.1 Chemistry and Types of Metallic Bonds Single layer metallic bonds have a layer height of only the average grit size and a high grit protrusion of 20-70 % of the grit diameter. Because of the high gritperformance, single layered wheels are limited to superabrasives. The metallic single-layer bonds are produced by electroplating, brazing, or […]
Polishing Tools
In the polishing process, the abrasive particles are finely dispersed in a liquid medium or binder and are directed over the workpiece surface by a counterbody [KLOC05a, p. 404]. Therefore, the polishing tool is rather a paste or suspension of abrasive grits in a medium or binder [MARI04, p. 442]. In plate polishing processes, a […]
Body Materials
The body material has to withstand the grinding forces, the centrifugal forces from wheel rotation, and the resulting internal stresses. In the grinding process, the body material should dampen vibrations and transfer heat. Furthermore, the body material needs to be shaped easily into the wanted geometry and should have low weight. These requirements translate into […]
Grinding Wheel Micro-design—Abrasive Layer and Wear
The performance of a grinding wheel, however, is not only a complicated function of all grinding wheel parameters such as grain nature and grain dimensions, nature of bond material, volumetric composition of the wheel etc., but, as said before, depends on the grinding conditions also [DECN70]. Micro-design of grinding wheels, i. e. structure and composition […]
Grit-Bond-Interface Wear
For resin bonded grinding tools grit break-out is the main wear mechanism and, therefore, the grit holding forces within the bond are essential for tool wear [TOML76]. Abrasive particles worn more than 50 % of their diameter are not likely to retain in the bond any more. Moreover, there are details in the literature that […]
Life Cycle Inventory of Grinding Processes
7.2.1 Evaluating Sustainability of Unit Processes In addition to economic, environmental and social sustainability, the technological dimension needs to be considered as a fourth dimension. Yuan et al. [YUAN12] suggest three strategies to increase sustainability in manufacturing processes: (1) Optimizing of the manufacturing technology by detecting and changing the parameters that affect material and energy […]